# -*- coding: utf-8 -*-

__version__   = '2.2.2'
__author__    = "Avinash Kak (kak@purdue.edu)"
__date__      = '2022-March-5'
__url__       = 'https://engineering.purdue.edu/kak/distDLS/DLStudio-2.2.2.html'
__copyright__ = "(C) 2022 Avinash Kak. Python Software Foundation."


import sys,os,os.path
import torch
import torch.nn as nn
import torch.nn.functional as F
import torchvision                  
import torchvision.transforms as tvt
import torch.optim as optim
import numpy as np
from PIL import ImageFilter
import numbers
import re
import math
import random
import copy
import matplotlib.pyplot as plt
import gzip
import pickle
import pymsgbox
import time
import logging

#______________________________  DLStudio Class Definition  ________________________________

class DLStudio(object):

    def __init__(self, *args, **kwargs ):
        if args:
            raise ValueError(  
                   '''DLStudio constructor can only be called with keyword arguments for 
                      the following keywords: epochs, learning_rate, batch_size, momentum,
                      convo_layers_config, image_size, dataroot, path_saved_model, classes, 
                      image_size, convo_layers_config, fc_layers_config, debug_train, use_gpu, and 
                      debug_test''')
        learning_rate = epochs = batch_size = convo_layers_config = momentum = None
        image_size = fc_layers_config = dataroot =  path_saved_model = classes = use_gpu = None
        debug_train  = debug_test = None
        if 'dataroot' in kwargs                      :   dataroot = kwargs.pop('dataroot')
        if 'learning_rate' in kwargs                 :   learning_rate = kwargs.pop('learning_rate')
        if 'momentum' in kwargs                      :   momentum = kwargs.pop('momentum')
        if 'epochs' in kwargs                        :   epochs = kwargs.pop('epochs')
        if 'batch_size' in kwargs                    :   batch_size = kwargs.pop('batch_size')
        if 'convo_layers_config' in kwargs           :   convo_layers_config = kwargs.pop('convo_layers_config')
        if 'image_size' in kwargs                    :   image_size = kwargs.pop('image_size')
        if 'fc_layers_config' in kwargs              :   fc_layers_config = kwargs.pop('fc_layers_config')
        if 'path_saved_model' in kwargs              :   path_saved_model = kwargs.pop('path_saved_model')
        if 'classes' in kwargs                       :   classes = kwargs.pop('classes') 
        if 'use_gpu' in kwargs                       :   use_gpu = kwargs.pop('use_gpu') 
        if 'debug_train' in kwargs                   :   debug_train = kwargs.pop('debug_train') 
        if 'debug_test' in kwargs                    :   debug_test = kwargs.pop('debug_test') 
        if len(kwargs) != 0: raise ValueError('''You have provided unrecognizable keyword args''')
        if dataroot:
            self.dataroot = dataroot
        if convo_layers_config:
            self.convo_layers_config = convo_layers_config
        if image_size:
            self.image_size = image_size
        if fc_layers_config:
            self.fc_layers_config = fc_layers_config
#            if fc_layers_config[0] is not -1:
            if fc_layers_config[0] != -1:
                raise Exception("""\n\n\nYour 'fc_layers_config' construction option is not correct. """
                                """The first element of the list of nodes in the fc layer must be -1 """
                                """because the input to fc will be set automatically to the size of """
                                """the final activation volume of the convolutional part of the network""")
        if  path_saved_model:
            self.path_saved_model = path_saved_model
        if classes:
            self.class_labels = classes
        if learning_rate:
            self.learning_rate = learning_rate
        else:
            self.learning_rate = 1e-6
        if momentum:
            self.momentum = momentum
        if epochs:
            self.epochs = epochs
        if batch_size:
            self.batch_size = batch_size
        if use_gpu is not None:
            self.use_gpu = use_gpu
            if use_gpu is True:
                if torch.cuda.is_available():
                    self.device = torch.device("cuda:0")
                else:
                    raise Exception("You requested GPU support, but there's no GPU on this machine")
            else:
                self.device = torch.device("cpu")
        if debug_train:                             
            self.debug_train = debug_train
        else:
            self.debug_train = 0
        if debug_test:                             
            self.debug_test = debug_test
        else:
            self.debug_test = 0
        self.debug_config = 0
#        self.device = torch.device("cuda:0" if torch.cuda.is_available() and self.use_gpu is False else "cpu")

    def parse_config_string_for_convo_layers(self):
        '''
        Each collection of 'n' otherwise identical layers in a convolutional network is 
        specified by a string that looks like:

                                 "nx[a,b,c,d]-MaxPool(k)"
        where 
                n      =  num of this type of convo layer
                a      =  number of out_channels                      [in_channels determined by prev layer] 
                b,c    =  kernel for this layer is of size (b,c)      [b along height, c along width]
                d      =  stride for convolutions
                k      =  maxpooling over kxk patches with stride of k

        Example:
                     "n1x[a1,b1,c1,d1]-MaxPool(k1)  n2x[a2,b2,c2,d2]-MaxPool(k2)"
        '''
        configuration = self.convo_layers_config
        configs = configuration.split()
        all_convo_layers = []
        image_size_after_layer = self.image_size
        for k,config in enumerate(configs):
            two_parts = config.split('-')
            how_many_conv_layers_with_this_config = int(two_parts[0][:config.index('x')])
            if self.debug_config:
                print("\n\nhow many convo layers with this config: %d" % how_many_conv_layers_with_this_config)
            maxpooling_size = int(re.findall(r'\d+', two_parts[1])[0])
            if self.debug_config:
                print("\nmax pooling size for all convo layers with this config: %d" % maxpooling_size)
            for conv_layer in range(how_many_conv_layers_with_this_config):            
                convo_layer = {'out_channels':None, 
                               'kernel_size':None, 
                               'convo_stride':None, 
                               'maxpool_size':None,
                               'maxpool_stride': None}
                kernel_params = two_parts[0][config.index('x')+1:][1:-1].split(',')
                if self.debug_config:
                    print("\nkernel_params: %s" % str(kernel_params))
                convo_layer['out_channels'] = int(kernel_params[0])
                convo_layer['kernel_size'] = (int(kernel_params[1]), int(kernel_params[2]))
                convo_layer['convo_stride'] =  int(kernel_params[3])
                image_size_after_layer = [x // convo_layer['convo_stride'] for x in image_size_after_layer]
                convo_layer['maxpool_size'] = maxpooling_size
                convo_layer['maxpool_stride'] = maxpooling_size
                image_size_after_layer = [x // convo_layer['maxpool_size'] for x in image_size_after_layer]
                all_convo_layers.append(convo_layer)
        configs_for_all_convo_layers = {i : all_convo_layers[i] for i in range(len(all_convo_layers))}
        if self.debug_config:
            print("\n\nAll convo layers: %s" % str(configs_for_all_convo_layers))
        last_convo_layer = configs_for_all_convo_layers[len(all_convo_layers)-1]
        out_nodes_final_layer = image_size_after_layer[0] * image_size_after_layer[1] * \
                                                                      last_convo_layer['out_channels']
        self.fc_layers_config[0] = out_nodes_final_layer
        self.configs_for_all_convo_layers = configs_for_all_convo_layers
        return configs_for_all_convo_layers


    def build_convo_layers(self, configs_for_all_convo_layers):
        conv_layers = nn.ModuleList()
        in_channels_for_next_layer = None
        for layer_index in configs_for_all_convo_layers:
            if self.debug_config:
                print("\n\n\nLayer index: %d" % layer_index)
            in_channels = 3 if layer_index == 0 else in_channels_for_next_layer
            out_channels = configs_for_all_convo_layers[layer_index]['out_channels']
            kernel_size = configs_for_all_convo_layers[layer_index]['kernel_size']
            padding = tuple((k-1) // 2 for k in kernel_size)
            stride       = configs_for_all_convo_layers[layer_index]['convo_stride']
            maxpool_size = configs_for_all_convo_layers[layer_index]['maxpool_size']
            if self.debug_config:
                print("\n     in_channels=%d   out_channels=%d    kernel_size=%s     stride=%s    \
                maxpool_size=%s" % (in_channels, out_channels, str(kernel_size), str(stride), 
                str(maxpool_size)))
            conv_layers.append( nn.Conv2d( in_channels,out_channels,kernel_size,stride=stride,padding=padding) )
            conv_layers.append( nn.MaxPool2d( maxpool_size ) )
            conv_layers.append( nn.ReLU() ),
            in_channels_for_next_layer = out_channels
        return conv_layers

    def build_fc_layers(self):
        fc_layers = nn.ModuleList()
        for layer_index in range(len(self.fc_layers_config) - 1):
            fc_layers.append( nn.Linear( self.fc_layers_config[layer_index], 
                                                                self.fc_layers_config[layer_index+1] ) )
        return fc_layers            

    def load_cifar_10_dataset(self):       
        '''
        In the code shown below, the call to "ToTensor()" converts the usual int range 0-255 for pixel 
        values to 0-1.0 float vals and then the call to "Normalize()" changes the range to -1.0-1.0 float 
        vals. For additional explanation of the call to "tvt.ToTensor()", see Slide 31 of my Week 2 
        slides at the DL course website.  And see Slides 32 and 33 for the syntax 
        "tvt.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))".  In this call, the three numbers in the
        first tuple change the means in the three color channels and the three numbers in the second 
        tuple change the standard deviations according to the formula:

                 image_channel_val = (image_channel_val - mean) / std

        The end result is that the values in the image tensor will be normalized to fall between -1.0 
        and +1.0. If needed we can do inverse normalization  by

                 image_channel_val  =   (image_channel_val * std) + mean
        '''

        ##   But then the call to Normalize() changes the range to -1.0-1.0 float vals.
        transform = tvt.Compose([tvt.ToTensor(),
                                 tvt.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))])    ## accuracy: 51%
        ##  Define where the training and the test datasets are located:
        train_data_loc = torchvision.datasets.CIFAR10(root=self.dataroot, train=True, download=True, transform=transform)
        test_data_loc = torchvision.datasets.CIFAR10(root=self.dataroot, train=False, download=True, transform=transform)
        ##  Now create the data loaders:
        self.train_data_loader = torch.utils.data.DataLoader(train_data_loc,batch_size=self.batch_size, shuffle=True, num_workers=2)
        self.test_data_loader = torch.utils.data.DataLoader(test_data_loc,batch_size=self.batch_size, shuffle=False, num_workers=2)

    def load_cifar_10_dataset_with_augmentation(self):             
        '''
        In general, we want to do data augmentation for training:
        '''
        transform_train = tvt.Compose([
                                  tvt.RandomCrop(32, padding=4),
                                  tvt.RandomHorizontalFlip(),
                                  tvt.ToTensor(),
                                  tvt.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))])        
        ##  Don't need any augmentation for the test data: 
        transform_test = tvt.Compose([
                               tvt.ToTensor(),
                               tvt.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))])
        ##  Define where the training and the test datasets are located
        train_data_loc = torchvision.datasets.CIFAR10(
                        root=self.dataroot, train=True, download=True, transform=transform_train)
        test_data_loc = torchvision.datasets.CIFAR10(
                      root=self.dataroot, train=False, download=True, transform=transform_test)
        ##  Now create the data loaders:
        self.train_data_loader = torch.utils.data.DataLoader(train_data_loc, batch_size=self.batch_size, 
                                                                     shuffle=True, num_workers=2)
        self.test_data_loader = torch.utils.data.DataLoader(test_data_loc, batch_size=self.batch_size, 
                                                                 shuffle=False, num_workers=2)

    def imshow(self, img):
        '''
        called by display_tensor_as_image() for displaying the image
        '''
        img = img / 2 + 0.5     # unnormalize
        npimg = img.numpy()
        plt.imshow(np.transpose(npimg, (1, 2, 0)))
        plt.show()

    class Net(nn.Module):
        def __init__(self, convo_layers, fc_layers):
            super(DLStudio.Net, self).__init__()
            self.my_modules_convo = convo_layers
            self.my_modules_fc = fc_layers
        def forward(self, x):
            for m in self.my_modules_convo:
                x = m(x)
            x = x.view(x.size(0), -1)
            for m in self.my_modules_fc:
                x = m(x)
            return x


    def run_code_for_training(self, net, display_images=False):        
        filename_for_out = "performance_numbers_" + str(self.epochs) + ".txt"
        FILE = open(filename_for_out, 'w')
        net = copy.deepcopy(net)
        net = net.to(self.device)
        criterion = nn.CrossEntropyLoss()
        optimizer = optim.SGD(net.parameters(), lr=self.learning_rate, momentum=self.momentum)
        print("\n\nStarting training loop...")
        start_time = time.perf_counter()
        loss_tally = []
        elapsed_time = 0.0
        for epoch in range(self.epochs):  
            print("")
            running_loss = 0.0
            for i, data in enumerate(self.train_data_loader):
                inputs, labels = data
                if i % 1000 == 999:
                    current_time = time.perf_counter()
                    elapsed_time = current_time - start_time 
                    print("\n\n[epoch:%d/%d  iter=%4d  elapsed_time=%5d secs]   Ground Truth:     " % 
                          (epoch+1, self.epochs, i+1, elapsed_time) + 
                          ' '.join('%10s' % self.class_labels[labels[j]] for j in range(self.batch_size)))
                inputs = inputs.to(self.device)
                labels = labels.to(self.device)
                ##  Since PyTorch likes to construct dynamic computational graphs, we need to
                ##  zero out the previously calculated gradients for the learnable parameters:
                optimizer.zero_grad()
                outputs = net(inputs)
                loss = criterion(outputs, labels)
                running_loss += loss.item()
                if i % 1000 == 999:
                    _, predicted = torch.max(outputs.data, 1)
                    print("[epoch:%d/%d  iter=%4d  elapsed_time=%5d secs]   Predicted Labels: " % 
                     (epoch+1, self.epochs, i+1, elapsed_time ) +
                     ' '.join('%10s' % self.class_labels[predicted[j]] for j in range(self.batch_size)))
                    avg_loss = running_loss / float(2000)
                    loss_tally.append(avg_loss)
                    print("[epoch:%d/%d  iter=%4d  elapsed_time=%5d secs]   Loss: %.3f" % 
                                                                   (epoch+1, self.epochs, i+1, elapsed_time, avg_loss))    
                    FILE.write("%.3f\n" % avg_loss)
                    FILE.flush()
                    running_loss = 0.0
                    if display_images:
                        logger = logging.getLogger()
                        old_level = logger.level
                        logger.setLevel(100)
                        plt.figure(figsize=[6,3])
                        plt.imshow(np.transpose(torchvision.utils.make_grid(inputs, 
                                                            normalize=False, padding=3, pad_value=255).cpu(), (1,2,0)))
                        plt.show()
                        logger.setLevel(old_level)
                loss.backward()
                optimizer.step()
        print("\nFinished Training\n")
        self.save_model(net)
        plt.figure(figsize=(10,5))
        plt.title("Labeling Loss vs. Iterations")
        plt.plot(loss_tally)
        plt.xlabel("iterations")
        plt.ylabel("loss")
        plt.legend()
        plt.savefig("playing_with_skips_loss.png")
        plt.show()


    def display_tensor_as_image(self, tensor, title=""):
        '''
        This method converts the argument tensor into a photo image that you can display
        in your terminal screen. It can convert tensors of three different shapes
        into images: (3,H,W), (1,H,W), and (H,W), where H, for height, stands for the
        number of pixels in the vertical direction and W, for width, for the same
        along the horizontal direction.  When the first element of the shape is 3,
        that means that the tensor represents a color image in which each pixel in
        the (H,W) plane has three values for the three color channels.  On the other
        hand, when the first element is 1, that stands for a tensor that will be
        shown as a grayscale image.  And when the shape is just (H,W), that is
        automatically taken to be for a grayscale image.
        '''
        tensor_range = (torch.min(tensor).item(), torch.max(tensor).item())
        if tensor_range == (-1.0,1.0):
            ##  The tensors must be between 0.0 and 1.0 for the display:
            print("\n\n\nimage un-normalization called")
            tensor = tensor/2.0 + 0.5     # unnormalize
        plt.figure(title)
        ###  The call to plt.imshow() shown below needs a numpy array. We must also
        ###  transpose the array so that the number of channels (the same thing as the
        ###  number of color planes) is in the last element.  For a tensor, it would be in
        ###  the first element.
        if tensor.shape[0] == 3 and len(tensor.shape) == 3:
#            plt.imshow( tensor.numpy().transpose(1,2,0) )
            plt.imshow( tensor.numpy().transpose(1,2,0) )
        ###  If the grayscale image was produced by calling torchvision.transform's
        ###  ".ToPILImage()", and the result converted to a tensor, the tensor shape will
        ###  again have three elements in it, however the first element that stands for
        ###  the number of channels will now be 1
        elif tensor.shape[0] == 1 and len(tensor.shape) == 3:
            tensor = tensor[0,:,:]
            plt.imshow( tensor.numpy(), cmap = 'gray' )
        ###  For any one color channel extracted from the tensor representation of a color
        ###  image, the shape of the tensor will be (W,H):
        elif len(tensor.shape) == 2:
            plt.imshow( tensor.numpy(), cmap = 'gray' )
        else:
            sys.exit("\n\n\nfrom 'display_tensor_as_image()': tensor for image is ill formed -- aborting")
        plt.show()

    def check_a_sampling_of_images(self):
        '''
        Displays the first batch_size number of images in your dataset.
        '''
        dataiter = iter(self.train_data_loader)
        images, labels = dataiter.next()
        # Since negative pixel values make no sense for display, setting the 'normalize' 
        # option to True will change the range back from (-1.0,1.0) to (0.0,1.0):
        self.display_tensor_as_image(torchvision.utils.make_grid(images, normalize=True))
        # Print class labels for the images shown:
        print(' '.join('%5s' % self.class_labels[labels[j]] for j in range(self.batch_size)))

    def save_model(self, model):
        '''
        Save the trained model to a disk file
        '''
        torch.save(model.state_dict(), self.path_saved_model)


    def run_code_for_testing(self, net, display_images=False):
        net.load_state_dict(torch.load(self.path_saved_model))
        net = net.eval()
        net = net.to(self.device)
        ##  In what follows, in addition to determining the predicted label for each test
        ##  image, we will also compute some stats to measure the overall performance of
        ##  the trained network.  This we will do in two different ways: For each class,
        ##  we will measure how frequently the network predicts the correct labels.  In
        ##  addition, we will compute the confusion matrix for the predictions.
        filename_for_results = "classification_results_" + str(self.epochs) + ".txt"
        FILE = open(filename_for_results, 'w')
        correct = 0
        total = 0
        confusion_matrix = torch.zeros(len(self.class_labels), len(self.class_labels))
        class_correct = [0] * len(self.class_labels)
        class_total = [0] * len(self.class_labels)
        with torch.no_grad():
            for i,data in enumerate(self.test_data_loader):
                ##  data is set to the images and the labels for one batch at a time:
                images, labels = data
                images = images.to(self.device)
                labels = labels.to(self.device)
                if i % 1000 == 999:
                    print("\n\n[i=%d:] Ground Truth:     " % (i+1) + ' '.join('%5s' % self.class_labels[labels[j]] 
                                                                   for j in range(self.batch_size)))
                outputs = net(images)
                ##  max() returns two things: the max value and its index in the 10 element
                ##  output vector.  We are only interested in the index --- since that is 
                ##  essentially the predicted class label:
                _, predicted = torch.max(outputs.data, 1)#
#                if display_images and i % 1000 == 999:
                if i % 1000 == 999:
                    print("[i=%d:] Predicted Labels: " % (i+1) + ' '.join('%5s' % self.class_labels[predicted[j]]
                                                              for j in range(self.batch_size)))
                    logger = logging.getLogger()
                    old_level = logger.level
                    if display_images:
                        logger.setLevel(100)
                        plt.figure(figsize=[6,3])
                        plt.imshow(np.transpose(torchvision.utils.make_grid(images,
                                                      normalize=False, padding=3, pad_value=255).cpu(), (1,2,0)))
                        plt.show()
                        logger.setLevel(old_level)
                for label,prediction in zip(labels,predicted):
                        confusion_matrix[label][prediction] += 1
                total += labels.size(0)
                correct += (predicted == labels).sum().item()
                ##  comp is a list of size batch_size of "True" and "False" vals
                comp = predicted == labels       
                for j in range(self.batch_size):
                    label = labels[j]
                    ##  The following works because, in a numeric context, the boolean value
                    ##  "False" is the same as number 0 and the boolean value True is the 
                    ##  same as number 1. For that reason "4 + True" will evaluate to 5 and
                    ##  "4 + False" will evaluate to 4.  Also, "1 == True" evaluates to "True"
                    ##  "1 == False" evaluates to "False".  However, note that "1 is True" 
                    ##  evaluates to "False" because the operator "is" does not provide a 
                    ##  numeric context for "True". And so on.  In the statement that follows,
                    ##  while  c[j].item() will either return "False" or "True", for the 
                    ##  addition operator, Python will use the values 0 and 1 instead.
                    class_correct[label] += comp[j].item()
                    class_total[label] += 1
        for j in range(len(self.class_labels)):
            print('Prediction accuracy for %5s : %2d %%' % (self.class_labels[j], 100 * class_correct[j] / class_total[j]))
            FILE.write('\n\nPrediction accuracy for %5s : %2d %%\n' % (self.class_labels[j], 100 * class_correct[j] / class_total[j]))
        print("\n\n\nOverall accuracy of the network on the 10000 test images: %d %%" % (100 * correct / float(total)))
        FILE.write("\n\n\nOverall accuracy of the network on the 10000 test images: %d %%\n" % (100 * correct / float(total)))
        print("\n\nDisplaying the confusion matrix:\n")
        FILE.write("\n\nDisplaying the confusion matrix:\n\n")
        out_str = "         "
        for j in range(len(self.class_labels)):  out_str +=  "%7s" % self.class_labels[j]   
        print(out_str + "\n")
        FILE.write(out_str + "\n\n")
        for i,label in enumerate(self.class_labels):
            out_percents = [100 * confusion_matrix[i,j] / float(class_total[i]) 
                                                      for j in range(len(self.class_labels))]
            out_percents = ["%.2f" % item.item() for item in out_percents]
            out_str = "%6s:  " % self.class_labels[i]
            for j in range(len(self.class_labels)): out_str +=  "%7s" % out_percents[j]
            print(out_str)
            FILE.write(out_str + "\n")
        FILE.close()        


    ###%%%
    ########################################################################################
    ###############  Start Definition of Inner Class ExperimentsWithSequential #############

    class ExperimentsWithSequential(nn.Module):                                
        """
        Demonstrates how to use the torch.nn.Sequential container class

        Class Path:  DLStudio  ->  ExperimentsWithSequential    
        """
        def __init__(self, dl_studio ):
            super(DLStudio.ExperimentsWithSequential, self).__init__()
            self.dl_studio = dl_studio

        def load_cifar_10_dataset(self):       
            self.dl_studio.load_cifar_10_dataset()

        def load_cifar_10_dataset_with_augmentation(self):             
            self.dl_studio.load_cifar_10_dataset_with_augmentation()

        class Net(nn.Module):
            """
            To see if the DLStudio class would work with any network that a user may want
            to experiment with, I copy-and-pasted the network shown below from the following
            page by Zhenye at GitHub:
                         https://zhenye-na.github.io/2018/09/28/pytorch-cnn-cifar10.html

            Class Path:  DLStudio  ->  ExperimentsWithSequential  ->  Net
            """
            def __init__(self):
                super(DLStudio.ExperimentsWithSequential.Net, self).__init__()
                self.conv_seqn = nn.Sequential(
                    # Conv Layer block 1:
                    nn.Conv2d(in_channels=3, out_channels=32, kernel_size=3, padding=1),
                    nn.BatchNorm2d(32),
                    nn.ReLU(inplace=True),
                    nn.Conv2d(in_channels=32, out_channels=64, kernel_size=3, padding=1),
                    nn.ReLU(inplace=True),
                    nn.MaxPool2d(kernel_size=2, stride=2),
                    # Conv Layer block 2:
                    nn.Conv2d(in_channels=64, out_channels=128, kernel_size=3, padding=1),
                    nn.BatchNorm2d(128),
                    nn.ReLU(inplace=True),
                    nn.Conv2d(in_channels=128, out_channels=128, kernel_size=3, padding=1),
                    nn.ReLU(inplace=True),
                    nn.MaxPool2d(kernel_size=2, stride=2),
                    nn.Dropout2d(p=0.05),
                    # Conv Layer block 3:
                    nn.Conv2d(in_channels=128, out_channels=256, kernel_size=3, padding=1),
                    nn.BatchNorm2d(256),
                    nn.ReLU(inplace=True),
                    nn.Conv2d(in_channels=256, out_channels=256, kernel_size=3, padding=1),
                    nn.ReLU(inplace=True),
                    nn.MaxPool2d(kernel_size=2, stride=2),
                )
                self.fc_seqn = nn.Sequential(
                    nn.Dropout(p=0.1),
                    nn.Linear(4096, 1024),
                    nn.ReLU(inplace=True),
                    nn.Linear(1024, 512),
                    nn.ReLU(inplace=True),
                    nn.Dropout(p=0.1),
                    nn.Linear(512, 10)
                )
    
            def forward(self, x):
                x = self.conv_seqn(x)
                # flatten
                x = x.view(x.size(0), -1)
                x = self.fc_seqn(x)
                return x

        def run_code_for_training(self, net):        
            self.dl_studio.run_code_for_training(net)

        def save_model(self, model):
            '''
            Save the trained model to a disk file
            '''
            torch.save(model.state_dict(), self.dl_studio.path_saved_model)

        def run_code_for_testing(self, model):
            self.dl_studio.run_code_for_testing(model)

    ###%%%
    ########################################################################################
    ##################  Start Definition of Inner Class ExperimentsWithCIFAR ###############

    class ExperimentsWithCIFAR(nn.Module):              
        """
        Class Path:  DLStudio  ->  ExperimentsWithCIFAR
        """

        def __init__(self, dl_studio ):
            super(DLStudio.ExperimentsWithCIFAR, self).__init__()
            self.dl_studio = dl_studio

        def load_cifar_10_dataset(self):       
            self.dl_studio.load_cifar_10_dataset()

        def load_cifar_10_dataset_with_augmentation(self):             
            self.dl_studio.load_cifar_10_dataset_with_augmentation()

        ##  You can instantiate two different types of networks when experimenting with 
        ##  the inner class ExperimentsWithCIFAR.  The network shown below is from the 
        ##  PyTorch tutorial
        ##
        ##     https://pytorch.org/tutorials/beginner/blitz/cifar10_tutorial.html
        ##
        class Net(nn.Module):
            """
            Class Path:  DLStudio  ->  ExperimentsWithCIFAR  ->  Net
            """
            def __init__(self):
                super(DLStudio.ExperimentsWithCIFAR.Net, self).__init__()
                self.conv1 = nn.Conv2d(3, 6, 5)
                self.conv2 = nn.Conv2d(6, 16, 5)
                self.fc1 = nn.Linear(16 * 5 * 5, 120)
                self.fc2 = nn.Linear(120, 84)
                self.fc3 = nn.Linear(84, 10)
        
            def forward(self, x):
                x = nn.MaxPool2d(2,2)(F.relu(self.conv1(x)))
                x = nn.MaxPool2d(2,2)(F.relu(self.conv2(x)))
                x = x.view(-1, 16 * 5 * 5)
                x = F.relu(self.fc1(x))
                x = F.relu(self.fc2(x))
                x = self.fc3(x)
                return x

        ##  Instead of using the network shown above, you can also use the network shown below.
        ##  if you are playing with the ExperimentsWithCIFAR inner class. If that's what you
        ##  want to do, in the script "playing_with_cifar10.py" in the Examples directory,
        ##  you will need to replace the statement
        ##                          model = exp_cifar.Net()
        ##  by the statement
        ##                          model = exp_cifar.Net2()        
        ##
        class Net2(nn.Module):
            """
            Class Path:  DLStudio  ->  ExperimentsWithCIFAR  ->  Net2
            """
            def __init__(self):
                """
                I created this network class just to see if it was possible to simply calculate
                the size of the first of the fully connected layers from strides in the convo
                layers up to that point and from the out_channels used in the top-most convo 
                layer.   In what you see below, I am keeping track of all the strides by pushing 
                them into the array 'strides'.  Subsequently, in the formula shown in line (A),
                I use the product of all strides and the number of out_channels for the topmost
                layer to compute the size of the first fully-connected layer.
                """
                super(DLStudio.ExperimentsWithCIFAR.Net2, self).__init__()
                self.relu = nn.ReLU()
                strides = []
                patch_size = 2
                ## conv1:
                out_ch, ker_size, conv_stride, pool_stride = 128,5,1,2
                self.conv1 = nn.Conv2d(3, out_ch, (ker_size,ker_size), padding=(ker_size-1)//2)     
                self.pool1 = nn.MaxPool2d(patch_size, pool_stride)     
                strides += (conv_stride, pool_stride)
                ## conv2:
                in_ch = out_ch
                out_ch, ker_size, conv_stride, pool_stride = 128,3,1,2
                self.conv2 = nn.Conv2d(in_ch, out_ch, ker_size, padding=(ker_size-1)//2)
                self.pool2 = nn.MaxPool2d(patch_size, pool_stride)     
                strides += (conv_stride, pool_stride)
                ## conv3:                   
                ## meant for repeated invocation, must have same in_ch, out_ch and strides of 1
                in_ch = out_ch
                out_ch, ker_size, conv_stride, pool_stride = in_ch,2,1,1
                self.conv3 = nn.Conv2d(in_ch, out_ch, ker_size, padding=1)
                self.pool3 = nn.MaxPool2d(patch_size, pool_stride)         
#                strides += (conv_stride, pool_stride)
                ## figure out the number of nodes needed for entry into fc:
                in_size_for_fc = out_ch * (32 // np.prod(strides)) ** 2                    ## (A)
                self.in_size_for_fc = in_size_for_fc
                self.fc1 = nn.Linear(in_size_for_fc, 150)
                self.fc2 = nn.Linear(150, 100)
                self.fc3 = nn.Linear(100, 10)
        
            def forward(self, x):
                ##  We know that forward() begins its with work x shaped as (4,3,32,32) where
                ##  4 is the batch size, 3 in_channels, and where the input image size is 32x32.
                x = self.relu(self.conv1(x))  
                x = self.pool1(x)             
                x = self.relu(self.conv2(x))
                x = self.pool2(x)             
                x = self.pool3(self.relu(self.conv3(x)))
                x = x.view(-1, self.in_size_for_fc)
                x = self.relu(self.fc1( x ))
                x = self.relu(self.fc2( x ))
                x = self.fc3(x)
                return x

        def run_code_for_training(self, net, display_images=False):
            self.dl_studio.run_code_for_training(net, display_images)
            
        def save_model(self, model):
            '''
            Save the trained model to a disk file
            '''
            torch.save(model.state_dict(), self.dl_studio.path_saved_model)

        def run_code_for_testing(self, model, display_images=False):
            self.dl_studio.run_code_for_testing(model, display_images)


    ###%%%
    ########################################################################################
    ###################  Start Definition of Inner Class SkipConnections  ##################

    class SkipConnections(nn.Module):             
        """
        This educational class is meant for illustrating the concepts related to the 
        use of skip connections in neural network.  It is now well known that deep
        networks are difficult to train because of the vanishing gradients problem.
        What that means is that as the depth of network increases, the loss gradients
        calculated for the early layers become more and more muted, which suppresses
        the learning of the parameters in those layers.  An important mitigation
        strategy for addressing this problem consists of creating a CNN using blocks
        with skip connections.

        With the code shown in this inner class of the module, you can now experiment
        with skip connections in a CNN to see how a deep network with this feature
        might improve the classification results.  As you will see in the code shown
        below, the network that allows you to construct a CNN with skip connections
        is named BMEnet.  As shown in the script playing_with_skip_connections.py in
        the Examples directory of the distribution, you can easily create a CNN with
        arbitrary depth just by using the "depth" constructor option for the BMEnet
        class.  The basic block of the network constructed by BMEnet is called
        SkipBlock which, very much like the BasicBlock in ResNet-18, has a couple of
        convolutional layers whose output is combined with the input to the block.
    
        Note that the value given to the "depth" constructor option for the
        BMEnet class does NOT translate directly into the actual depth of the
        CNN. [Again, see the script playing_with_skip_connections.py in the Examples
        directory for how to use this option.] The value of "depth" is translated
        into how many instances of SkipBlock to use for constructing the CNN.

        Class Path:  DLStudio  ->  SkipConnections
        """
        def __init__(self, dl_studio):
            super(DLStudio.SkipConnections, self).__init__()
            self.dl_studio = dl_studio

        def load_cifar_10_dataset(self):       
            self.dl_studio.load_cifar_10_dataset()

        def load_cifar_10_dataset_with_augmentation(self):             
            self.dl_studio.load_cifar_10_dataset_with_augmentation()


        class SkipBlock(nn.Module):
            """
            Class Path:   DLStudio  ->  SkipConnections  ->  SkipBlock
            """            
            def __init__(self, in_ch, out_ch, downsample=False, skip_connections=True):
                super(DLStudio.SkipConnections.SkipBlock, self).__init__()
                self.downsample = downsample
                self.skip_connections = skip_connections
                self.in_ch = in_ch
                self.out_ch = out_ch
                self.convo1 = nn.Conv2d(in_ch, out_ch, 3, stride=1, padding=1)
                self.convo2 = nn.Conv2d(in_ch, out_ch, 3, stride=1, padding=1)
                self.bn1 = nn.BatchNorm2d(out_ch)
                self.bn2 = nn.BatchNorm2d(out_ch)
                if downsample:
                    ##  Setting stride to 2 and kernel_size to 1 amounts to retaining every
                    ##  other pixel in the image --- which halves the size of the image:
                    self.downsampler = nn.Conv2d(in_ch, out_ch, 1, stride=2)

            def forward(self, x):
                identity = x                                     
                out = self.convo1(x)                              
                out = self.bn1(out)                              
                out = torch.nn.functional.relu(out)
                if self.in_ch == self.out_ch:
                    out = self.convo2(out)                              
                    out = self.bn2(out)                              
                    out = torch.nn.functional.relu(out)
                if self.downsample:
                    out = self.downsampler(out)
                    identity = self.downsampler(identity)
                if self.skip_connections:
                    if self.in_ch == self.out_ch:
                        out += identity                              
                    else:
                        ## To understand the following assignments, recall that the data has the
                        ## shape [B,C,H,W]. So it is the second axis that corresponds to the channels
                        out[:,:self.in_ch,:,:] += identity
                        out[:,self.in_ch:,:,:] += identity
                return out


        class BMEnet(nn.Module):
            """
            Class Path:   DLStudio  ->  SkipConnections  ->  BMEnet
            """
            def __init__(self, skip_connections=True, depth=32):
                super(DLStudio.SkipConnections.BMEnet, self).__init__()
                if depth not in [8, 16, 32, 64]:
                    sys.exit("BMEnet has been tested for depth for only 8, 16, 32, and 64")
                self.depth = depth // 8
                self.conv = nn.Conv2d(3, 64, 3, padding=1)
                self.pool = nn.MaxPool2d(2, 2)
                self.skip64_arr = nn.ModuleList()
                for i in range(self.depth):
                    self.skip64_arr.append(DLStudio.SkipConnections.SkipBlock(64, 64,
                                                          skip_connections=skip_connections))
                self.skip64ds = DLStudio.SkipConnections.SkipBlock(64, 64, 
                                            downsample=True, skip_connections=skip_connections)
                self.skip64to128 = DLStudio.SkipConnections.SkipBlock(64, 128, 
                                                            skip_connections=skip_connections )
                self.skip128_arr = nn.ModuleList()
                for i in range(self.depth):
                    self.skip128_arr.append(DLStudio.SkipConnections.SkipBlock(128, 128,
                                                         skip_connections=skip_connections))
                self.skip128ds = DLStudio.SkipConnections.SkipBlock(128,128,
                                            downsample=True, skip_connections=skip_connections)
                ##  The following declaration is predicated on the assumption that the number of
                ##  output nodes (CxHxW) from the final convo layer exactly 2048 for each
                ##  input image.  Depending on the size of the input image, this places a constraint
                ##  on how many downsampling instances of SkipBlock you can call in a network.
                self.fc1 =  nn.Linear(2048, 1000)
                self.fc2 =  nn.Linear(1000, 10)

            def forward(self, x):
                x = self.pool(torch.nn.functional.relu(self.conv(x)))          
                for i,skip64 in enumerate(self.skip64_arr[:self.depth//4]):
                    x = skip64(x)                
                x = self.skip64ds(x)
                for i,skip64 in enumerate(self.skip64_arr[self.depth//4:]):
                    x = skip64(x)                
                x = self.skip64ds(x)
                x = self.skip64to128(x)
                for i,skip128 in enumerate(self.skip128_arr[:self.depth//4]):
                    x = skip128(x)                
                #  x = self.skip128ds(x)                                                       ## (A)
                for i,skip128 in enumerate(self.skip128_arr[self.depth//4:]):
                    x = skip128(x)                
                ## See the comment block above the "self.fc1" declaration in the constructor code.
                x = x.view(-1, 2048 )
                x = torch.nn.functional.relu(self.fc1(x))
                x = self.fc2(x)
                return x            

        def run_code_for_training(self, net, display_images=False):        
            self.dl_studio.run_code_for_training(net, display_images)
            
        def save_model(self, model):
            '''
            Save the trained model to a disk file
            '''
            torch.save(model.state_dict(), self.dl_studio.path_saved_model)

        def run_code_for_testing(self, model, display_images=False):
            self.dl_studio.run_code_for_testing(model, display_images=False)


    ###%%%
    ########################################################################################
    #################  Start Definition of Inner Class CustomDataLoading  ##################

    class CustomDataLoading(nn.Module):             
        """This is a testbed for experimenting with a completely grounds-up attempt at
        designing a custom data loader.  Ordinarily, if the basic format of how the
        dataset is stored is similar to one of the datasets that the Torchvision
        module knows about, you can go ahead and use that for your own dataset.  At
        worst, you may need to carry out some light customizations depending on the
        number of classes involved, etc.

        However, if the underlying dataset is stored in a manner that does not look
        like anything in Torchvision, you have no choice but to supply yourself all
        of the data loading infrastructure.  That is what this inner class of the 
        DLStudio module is all about.

        The custom data loading exercise here is related to a dataset called
        PurdueShapes5 that contains 32x32 images of binary shapes belonging to the
        following five classes:

                       1.  rectangle
                       2.  triangle
                       3.  disk
                       4.  oval
                       5.  star

        The dataset was generated by randomizing the sizes and the orientations
        of these five patterns.  Since the patterns are rotated with a very simple
        non-interpolating transform, just the act of random rotations can introduce
        boundary and even interior noise in the patterns.

        Each 32x32 image is stored in the dataset as the following list:

                           [R, G, B, Bbox, Label]
        where
                R     :   is a 1024 element list of the values for the red component
                          of the color at all the pixels
           
                B     :   the same as above but for the green component of the color

                G     :   the same as above but for the blue component of the color

                Bbox  :   a list like [x1,y1,x2,y2] that defines the bounding box 
                          for the object in the image
           
                Label :   the shape of the object

        I serialize the dataset with Python's pickle module and then compress it with 
        the gzip module.  

        You will find the following dataset directories in the "data" subdirectory
        of Examples in the DLStudio distro:

               PurdueShapes5-10000-train.gz
               PurdueShapes5-1000-test.gz
               PurdueShapes5-20-train.gz
               PurdueShapes5-20-test.gz               

        The number that follows the main name string "PurdueShapes5-" is for the 
        number of images in the dataset.  

        You will find the last two datasets, with 20 images each, useful for debugging
        your logic for object detection and bounding-box regression.

        Class Path:   DLStudio  ->  CustomDataLoading
        """     
        def __init__(self, dl_studio, dataserver_train=None, dataserver_test=None, dataset_file_train=None, dataset_file_test=None):
            super(DLStudio.CustomDataLoading, self).__init__()
            self.dl_studio = dl_studio
            self.dataserver_train = dataserver_train
            self.dataserver_test = dataserver_test

        class PurdueShapes5Dataset(torch.utils.data.Dataset):
            """
            Class Path:   DLStudio  ->  CustomDataLoading  ->  PurdueShapes5Dataset
            """
            def __init__(self, dl_studio, train_or_test, dataset_file):
                super(DLStudio.CustomDataLoading.PurdueShapes5Dataset, self).__init__()
                if train_or_test == 'train' and dataset_file == "PurdueShapes5-10000-train.gz":
                    if os.path.exists("torch_saved_PurdueShapes5-10000_dataset.pt") and \
                              os.path.exists("torch_saved_PurdueShapes5_label_map.pt"):
                        print("\nLoading training data from the torch-saved archive")
                        self.dataset = torch.load("torch_saved_PurdueShapes5-10000_dataset.pt")
                        self.label_map = torch.load("torch_saved_PurdueShapes5_label_map.pt")
                        # reverse the key-value pairs in the label dictionary:
                        self.class_labels = dict(map(reversed, self.label_map.items()))
                    else: 
                        print("""\n\n\nLooks like this is the first time you will be loading in\n"""
                              """the dataset for this script. First time loading could take\n"""
                              """a minute or so.  Any subsequent attempts will only take\n"""
                              """a few seconds.\n\n\n""")
                        root_dir = dl_studio.dataroot
                        f = gzip.open(root_dir + dataset_file, 'rb')
                        dataset = f.read()
                        self.dataset, self.label_map = pickle.loads(dataset, encoding='latin1')
                        torch.save(self.dataset, "torch_saved_PurdueShapes5-10000_dataset.pt")
                        torch.save(self.label_map, "torch_saved_PurdueShapes5_label_map.pt")
                        # reverse the key-value pairs in the label dictionary:
                        self.class_labels = dict(map(reversed, self.label_map.items()))
                else:
                    root_dir = dl_studio.dataroot
                    f = gzip.open(root_dir + dataset_file, 'rb')
                    dataset = f.read()
                    self.dataset, self.label_map = pickle.loads(dataset, encoding='latin1')
                    # reverse the key-value pairs in the label dictionary:
                    self.class_labels = dict(map(reversed, self.label_map.items()))
             
            def __len__(self):
                return len(self.dataset)

            def __getitem__(self, idx):
                r = np.array( self.dataset[idx][0] )
                g = np.array( self.dataset[idx][1] )
                b = np.array( self.dataset[idx][2] )
                R,G,B = r.reshape(32,32), g.reshape(32,32), b.reshape(32,32)
                im_tensor = torch.zeros(3,32,32, dtype=torch.float)
                im_tensor[0,:,:] = torch.from_numpy(R)
                im_tensor[1,:,:] = torch.from_numpy(G)
                im_tensor[2,:,:] = torch.from_numpy(B)
                sample = {'image' : im_tensor, 
                          'bbox' : self.dataset[idx][3],                          
                          'label' : self.dataset[idx][4] }
                return sample

        def load_PurdueShapes5_dataset(self, dataserver_train, dataserver_test ):       
            transform = tvt.Compose([tvt.ToTensor(),
                                tvt.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))])  
            self.train_dataloader = torch.utils.data.DataLoader(dataserver_train,
                               batch_size=self.dl_studio.batch_size,shuffle=True, num_workers=4)
            self.test_dataloader = torch.utils.data.DataLoader(dataserver_test,
                               batch_size=self.dl_studio.batch_size,shuffle=False, num_workers=4)

        class SkipBlock(nn.Module):
            """
            Class Path:   DLStudio  ->  CustomDataLoading  ->  SkipBlock
            """
            def __init__(self, in_ch, out_ch, downsample=False, skip_connections=True):
                super(DLStudio.CustomDataLoading.SkipBlock, self).__init__()
                self.downsample = downsample
                self.skip_connections = skip_connections
                self.in_ch = in_ch
                self.out_ch = out_ch
                self.convo1 = nn.Conv2d(in_ch, out_ch, 3, stride=1, padding=1)
                self.convo2 = nn.Conv2d(in_ch, out_ch, 3, stride=1, padding=1)
                norm_layer1 = nn.BatchNorm2d
                norm_layer2 = nn.BatchNorm2d
                self.bn1 = norm_layer1(out_ch)
                self.bn2 = norm_layer2(out_ch)
                if downsample:
                    self.downsampler = nn.Conv2d(in_ch, out_ch, 1, stride=2)

            def forward(self, x):
                identity = x                                     
                out = self.convo1(x)                              
                out = self.bn1(out)                              
                out = torch.nn.functional.relu(out)
                if self.in_ch == self.out_ch:
                    out = self.convo2(out)                              
                    out = self.bn2(out)                              
                    out = torch.nn.functional.relu(out)
                if self.downsample:
                    out = self.downsampler(out)
                    identity = self.downsampler(identity)
                if self.skip_connections:
                    if self.in_ch == self.out_ch:
                        out += identity                              
                    else:
                        out[:,:self.in_ch,:,:] += identity
                        out[:,self.in_ch:,:,:] += identity
                return out

        class BMEnet(nn.Module):
            """
            Class Path:   DLStudio  ->  CustomDataLoading  ->  BMENet
            """
            def __init__(self, skip_connections=True, depth=32):
                super(DLStudio.CustomDataLoading.BMEnet, self).__init__()
                if depth not in [6, 16, 32, 64]:
                    sys.exit("BMEnet has been tested for depth for only 16, 32, and 64")
                self.depth = depth // 8
                self.conv = nn.Conv2d(3, 64, 3, padding=1)
#                self.pool = nn.MaxPool2d(2, 2)
                self.skip64_arr = nn.ModuleList()
                for i in range(self.depth):
                    self.skip64_arr.append(DLStudio.SkipConnections.SkipBlock(64, 64,
                                                          skip_connections=skip_connections))
                self.skip64ds = DLStudio.SkipConnections.SkipBlock(64, 64, 
                                            downsample=True, skip_connections=skip_connections)
                self.skip64to128 = DLStudio.SkipConnections.SkipBlock(64, 128, 
                                                            skip_connections=skip_connections )
                self.skip128_arr = nn.ModuleList()
                for i in range(self.depth):
                    self.skip128_arr.append(DLStudio.SkipConnections.SkipBlock(128, 128,
                                                         skip_connections=skip_connections))
                self.skip128ds = DLStudio.SkipConnections.SkipBlock(128,128,
                                            downsample=True, skip_connections=skip_connections)
                self.fc1 =  nn.Linear(2048, 1000)
                self.fc2 =  nn.Linear(1000, 10)

            def forward(self, x):
#                x = self.pool(torch.nn.functional.relu(self.conv(x)))          
                x = nn.MaxPool2d(2,2)(torch.nn.functional.relu(self.conv(x)))          
                for i,skip64 in enumerate(self.skip64_arr[:self.depth//4]):
                    x = skip64(x)                
                x = self.skip64ds(x)
                for i,skip64 in enumerate(self.skip64_arr[self.depth//4:]):
                    x = skip64(x)                
                x = self.skip64ds(x)
                x = self.skip64to128(x)
                for i,skip128 in enumerate(self.skip128_arr[:self.depth//4]):
                    x = skip128(x)                
                for i,skip128 in enumerate(self.skip128_arr[self.depth//4:]):
                    x = skip128(x)                
                x = x.view(-1, 2048 )
                x = torch.nn.functional.relu(self.fc1(x))
                x = self.fc2(x)
                return x            

        def run_code_for_training_with_custom_loading(self, net):        
            filename_for_out = "performance_numbers_" + str(self.dl_studio.epochs) + ".txt"
            FILE = open(filename_for_out, 'w')
            net = copy.deepcopy(net)
            net = net.to(self.dl_studio.device)
            criterion = nn.CrossEntropyLoss()
            optimizer = optim.SGD(net.parameters(), 
                         lr=self.dl_studio.learning_rate, momentum=self.dl_studio.momentum)
            for epoch in range(self.dl_studio.epochs):  
                running_loss = 0.0
                for i, data in enumerate(self.train_dataloader):
                    inputs, bounding_box, labels = data['image'], data['bbox'], data['label']
                    if self.dl_studio.debug_train and i % 1000 == 999:
                        print("\n\n\nlabels: %s" % str(labels))
                        print("\n\n\ntype of labels: %s" % type(labels))
                        print("\n\n[iter=%d:] Ground Truth:     " % (i+1) + 
                        ' '.join('%5s' % self.dataserver_train.class_labels[labels[j].item()] for j in range(self.dl_studio.batch_size)))
                    inputs = inputs.to(self.dl_studio.device)
                    labels = labels.to(self.dl_studio.device)
                    optimizer.zero_grad()
                    outputs = net(inputs)
                    loss = criterion(outputs, labels)
                    if self.dl_studio.debug_train and i % 1000 == 999:
                        _, predicted = torch.max(outputs.data, 1)
                        print("[iter=%d:] Predicted Labels: " % (i+1) + 
                         ' '.join('%5s' % self.dataserver.class_labels[predicted[j]] 
                                           for j in range(self.dl_studio.batch_size)))
                        self.dl_studio.display_tensor_as_image(torchvision.utils.make_grid(
             inputs, normalize=True), "see terminal for TRAINING results at iter=%d" % (i+1))
                    loss.backward()
                    optimizer.step()
                    running_loss += loss.item()
                    if i % 1000 == 999:    
                        avg_loss = running_loss / float(1000)
                        print("[epoch:%d, batch:%5d] loss: %.3f" % (epoch + 1, i + 1, avg_loss))
                        FILE.write("%.3f\n" % avg_loss)
                        FILE.flush()
                        running_loss = 0.0
            print("\nFinished Training\n")
            self.save_model(net)
            
        def save_model(self, model):
            '''
            Save the trained model to a disk file
            '''
            torch.save(model.state_dict(), self.dl_studio.path_saved_model)

        def run_code_for_testing_with_custom_loading(self, net):
            net.load_state_dict(torch.load(self.dl_studio.path_saved_model))
            correct = 0
            total = 0
            confusion_matrix = torch.zeros(len(self.dataserver_train.class_labels), 
                                           len(self.dataserver_train.class_labels))
            class_correct = [0] * len(self.dataserver_train.class_labels)
            class_total = [0] * len(self.dataserver_train.class_labels)
            with torch.no_grad():
                for i, data in enumerate(self.test_dataloader):
                    images, bounding_box, labels = data['image'], data['bbox'], data['label']
                    labels = labels.tolist()
                    if self.dl_studio.debug_test and i % 1000 == 0:
                        print("\n\n[i=%d:] Ground Truth:     " %i + ' '.join('%10s' % 
                          self.dataserver_train.class_labels[labels[j]] for j in range(self.dl_studio.batch_size)))
                    outputs = net(images)
                    ##  max() returns two things: the max value and its index in the 10 element
                    ##  output vector.  We are only interested in the index --- since that is 
                    ##  essentially the predicted class label:
                    _, predicted = torch.max(outputs.data, 1)
                    predicted = predicted.tolist()
                    if self.dl_studio.debug_test and i % 1000 == 0:
                        print("[i=%d:] Predicted Labels: " %i + ' '.join('%10s' % 
                          self.dataserver_train.class_labels[predicted[j]] for j in range(self.dl_studio.batch_size)))
                        self.dl_studio.display_tensor_as_image(
                              torchvision.utils.make_grid(images, normalize=True), 
                              "see terminal for test results at i=%d" % i)
                    for label,prediction in zip(labels,predicted):
                        confusion_matrix[label][prediction] += 1
                    total += len(labels)
                    correct +=  [predicted[ele] == labels[ele] for ele in range(len(predicted))].count(True)
                    comp = [predicted[ele] == labels[ele] for ele in range(len(predicted))]
                    for j in range(self.dl_studio.batch_size):
                        label = labels[j]
                        class_correct[label] += comp[j]
                        class_total[label] += 1
            print("\n")
            for j in range(len(self.dataserver_train.class_labels)):
                print('Prediction accuracy for %5s : %2d %%' % (
              self.dataserver_train.class_labels[j], 100 * class_correct[j] / class_total[j]))
            print("\n\n\nOverall accuracy of the network on the 10000 test images: %d %%" % 
                                                                   (100 * correct / float(total)))
            print("\n\nDisplaying the confusion matrix:\n")
            out_str = "                "
            for j in range(len(self.dataserver_train.class_labels)):  
                                 out_str +=  "%15s" % self.dataserver_train.class_labels[j]   
            print(out_str + "\n")
            for i,label in enumerate(self.dataserver_train.class_labels):
                out_percents = [100 * confusion_matrix[i,j] / float(class_total[i]) 
                                 for j in range(len(self.dataserver_train.class_labels))]
                out_percents = ["%.2f" % item.item() for item in out_percents]
                out_str = "%12s:  " % self.dataserver_train.class_labels[i]
                for j in range(len(self.dataserver_train.class_labels)): 
                                                       out_str +=  "%15s" % out_percents[j]
                print(out_str)
    
    ###%%%
    ########################################################################################
    ###################  Start Definition of Inner Class DetectAndLocalize  ################

    class DetectAndLocalize(nn.Module):             
        """
        The purpose of this inner class is to focus on object detection in images --- as
        opposed to image classification.  Most people would say that object detection
        is a more challenging problem than image classification because, in general,
        the former also requires localization.  The simplest interpretation of what
        is meant by localization is that the code that carries out object detection
        must also output a bounding-box rectangle for the object that was detected.

        You will find in this inner class some examples of LOADnet classes meant
        for solving the object detection and localization problem.  The acronym
        "LOAD" in "LOADnet" stands for

                    "LOcalization And Detection"

        The different network examples included here are LOADnet1, LOADnet2, and
        LOADnet3.  For now, only pay attention to LOADnet2 since that's the class I
        have worked with the most for the 1.0.7 distribution.

        Class Path:   DLStudio  ->  DetectAndLocalize
        """
        def __init__(self, dl_studio, dataserver_train=None, dataserver_test=None, dataset_file_train=None, dataset_file_test=None):
            super(DLStudio.DetectAndLocalize, self).__init__()
            self.dl_studio = dl_studio
            self.dataserver_train = dataserver_train
            self.dataserver_test = dataserver_test
            self.debug = False

        class PurdueShapes5Dataset(torch.utils.data.Dataset):
            """
            Class Path:   DLStudio  ->  DetectAndLocalize  ->  PurdueShapes5Dataset
            """
            def __init__(self, dl_studio, train_or_test, dataset_file):
                super(DLStudio.DetectAndLocalize.PurdueShapes5Dataset, self).__init__()
                if train_or_test == 'train' and dataset_file == "PurdueShapes5-10000-train.gz":
                    if os.path.exists("torch-saved-PurdueShapes5-10000-dataset.pt") and \
                              os.path.exists("torch-saved-PurdueShapes5-label-map.pt"):
                        print("\nLoading training data from the torch-saved archive")
                        self.dataset = torch.load("torch-saved-PurdueShapes5-10000-dataset.pt")
                        self.label_map = torch.load("torch-saved-PurdueShapes5-label-map.pt")
                        # reverse the key-value pairs in the label dictionary:
                        self.class_labels = dict(map(reversed, self.label_map.items()))
                    else: 
                        print("""\n\n\nLooks like this is the first time you will be loading in\n"""
                              """the dataset for this script. First time loading could take\n"""
                              """a minute or so.  Any subsequent attempts will only take\n"""
                              """a few seconds.\n\n\n""")
                        root_dir = dl_studio.dataroot
                        f = gzip.open(root_dir + dataset_file, 'rb')
                        dataset = f.read()
                        if sys.version_info[0] == 3:
                            self.dataset, self.label_map = pickle.loads(dataset, encoding='latin1')
                        else:
                            self.dataset, self.label_map = pickle.loads(dataset)
                        torch.save(self.dataset, "torch-saved-PurdueShapes5-10000-dataset.pt")
                        torch.save(self.label_map, "torch-saved-PurdueShapes5-label-map.pt")
                        # reverse the key-value pairs in the label dictionary:
                        self.class_labels = dict(map(reversed, self.label_map.items()))
                elif train_or_test == 'train' and dataset_file == "PurdueShapes5-10000-train-noise-20.gz":
                    if os.path.exists("torch-saved-PurdueShapes5-10000-dataset-noise-20.pt") and \
                              os.path.exists("torch-saved-PurdueShapes5-label-map.pt"):
                        print("\nLoading training data from the torch-saved archive")
                        self.dataset = torch.load("torch-saved-PurdueShapes5-10000-dataset-noise-20.pt")
                        self.label_map = torch.load("torch-saved-PurdueShapes5-label-map.pt")
                        # reverse the key-value pairs in the label dictionary:
                        self.class_labels = dict(map(reversed, self.label_map.items()))
                    else: 
                        print("""\n\n\nLooks like this is the first time you will be loading in\n"""
                              """the dataset for this script. First time loading could take\n"""
                              """a minute or so.  Any subsequent attempts will only take\n"""
                              """a few seconds.\n\n\n""")
                        root_dir = dl_studio.dataroot
                        f = gzip.open(root_dir + dataset_file, 'rb')
                        dataset = f.read()
                        if sys.version_info[0] == 3:
                            self.dataset, self.label_map = pickle.loads(dataset, encoding='latin1')
                        else:
                            self.dataset, self.label_map = pickle.loads(dataset)
                        torch.save(self.dataset, "torch-saved-PurdueShapes5-10000-dataset-noise-20.pt")
                        torch.save(self.label_map, "torch-saved-PurdueShapes5-label-map.pt")
                        # reverse the key-value pairs in the label dictionary:
                        self.class_labels = dict(map(reversed, self.label_map.items()))
                elif train_or_test == 'train' and dataset_file == "PurdueShapes5-10000-train-noise-50.gz":
                    if os.path.exists("torch-saved-PurdueShapes5-10000-dataset-noise-50.pt") and \
                              os.path.exists("torch-saved-PurdueShapes5-label-map.pt"):
                        print("\nLoading training data from the torch-saved archive")
                        self.dataset = torch.load("torch-saved-PurdueShapes5-10000-dataset-noise-50.pt")
                        self.label_map = torch.load("torch-saved-PurdueShapes5-label-map.pt")
                        # reverse the key-value pairs in the label dictionary:
                        self.class_labels = dict(map(reversed, self.label_map.items()))
                    else: 
                        print("""\n\n\nLooks like this is the first time you will be loading in\n"""
                              """the dataset for this script. First time loading could take\n"""
                              """a minute or so.  Any subsequent attempts will only take\n"""
                              """a few seconds.\n\n\n""")
                        root_dir = dl_studio.dataroot
                        f = gzip.open(root_dir + dataset_file, 'rb')
                        dataset = f.read()
                        if sys.version_info[0] == 3:
                            self.dataset, self.label_map = pickle.loads(dataset, encoding='latin1')
                        else:
                            self.dataset, self.label_map = pickle.loads(dataset)
                        torch.save(self.dataset, "torch-saved-PurdueShapes5-10000-dataset-noise-50.pt")
                        torch.save(self.label_map, "torch-saved-PurdueShapes5-label-map.pt")
                        # reverse the key-value pairs in the label dictionary:
                        self.class_labels = dict(map(reversed, self.label_map.items()))
                elif train_or_test == 'train' and dataset_file == "PurdueShapes5-10000-train-noise-80.gz":
                    if os.path.exists("torch-saved-PurdueShapes5-10000-dataset-noise-80.pt") and \
                              os.path.exists("torch-saved-PurdueShapes5-label-map.pt"):
                        print("\nLoading training data from the torch-saved archive")
                        self.dataset = torch.load("torch-saved-PurdueShapes5-10000-dataset-noise-80.pt")
                        self.label_map = torch.load("torch-saved-PurdueShapes5-label-map.pt")
                        # reverse the key-value pairs in the label dictionary:
                        self.class_labels = dict(map(reversed, self.label_map.items()))
                    else: 
                        print("""\n\n\nLooks like this is the first time you will be loading in\n"""
                              """the dataset for this script. First time loading could take\n"""
                              """a minute or so.  Any subsequent attempts will only take\n"""
                              """a few seconds.\n\n\n""")
                        root_dir = dl_studio.dataroot
                        f = gzip.open(root_dir + dataset_file, 'rb')
                        dataset = f.read()
                        if sys.version_info[0] == 3:
                            self.dataset, self.label_map = pickle.loads(dataset, encoding='latin1')
                        else:
                            self.dataset, self.label_map = pickle.loads(dataset)
                        torch.save(self.dataset, "torch-saved-PurdueShapes5-10000-dataset-noise-80.pt")
                        torch.save(self.label_map, "torch-saved-PurdueShapes5-label-map.pt")
                        # reverse the key-value pairs in the label dictionary:
                        self.class_labels = dict(map(reversed, self.label_map.items()))
                else:
                    root_dir = dl_studio.dataroot
                    f = gzip.open(root_dir + dataset_file, 'rb')
                    dataset = f.read()
                    if sys.version_info[0] == 3:
                        self.dataset, self.label_map = pickle.loads(dataset, encoding='latin1')
                    else:
                        self.dataset, self.label_map = pickle.loads(dataset)
                    # reverse the key-value pairs in the label dictionary:
                    self.class_labels = dict(map(reversed, self.label_map.items()))
             
            def __len__(self):
                return len(self.dataset)

            def __getitem__(self, idx):
                r = np.array( self.dataset[idx][0] )
                g = np.array( self.dataset[idx][1] )
                b = np.array( self.dataset[idx][2] )
                R,G,B = r.reshape(32,32), g.reshape(32,32), b.reshape(32,32)
                im_tensor = torch.zeros(3,32,32, dtype=torch.float)
                im_tensor[0,:,:] = torch.from_numpy(R)
                im_tensor[1,:,:] = torch.from_numpy(G)
                im_tensor[2,:,:] = torch.from_numpy(B)
                bb_tensor = torch.tensor(self.dataset[idx][3], dtype=torch.float)
                sample = {'image' : im_tensor, 
                          'bbox' : bb_tensor,
                          'label' : self.dataset[idx][4] }
                return sample

        def load_PurdueShapes5_dataset(self, dataserver_train, dataserver_test ):       
            self.train_dataloader = torch.utils.data.DataLoader(dataserver_train,
                               batch_size=self.dl_studio.batch_size,shuffle=True, num_workers=4)
            self.test_dataloader = torch.utils.data.DataLoader(dataserver_test,
                               batch_size=self.dl_studio.batch_size,shuffle=False, num_workers=4)
    
        class SkipBlock(nn.Module):
            """
            Class Path:   DLStudio  ->  DetectAndLocalize  ->  SkipBlock
            """
            def __init__(self, in_ch, out_ch, downsample=False, skip_connections=True):
                super(DLStudio.DetectAndLocalize.SkipBlock, self).__init__()
                self.downsample = downsample
                self.skip_connections = skip_connections
                self.in_ch = in_ch
                self.out_ch = out_ch
                self.convo1 = nn.Conv2d(in_ch, out_ch, 3, stride=1, padding=1)
                self.convo2 = nn.Conv2d(in_ch, out_ch, 3, stride=1, padding=1)
                norm_layer1 = nn.BatchNorm2d
                norm_layer2 = nn.BatchNorm2d
                self.bn1 = norm_layer1(out_ch)
                self.bn2 = norm_layer2(out_ch)
                if downsample:
                    self.downsampler = nn.Conv2d(in_ch, out_ch, 1, stride=2)
            def forward(self, x):
                identity = x                                     
                out = self.convo1(x)                              
                out = self.bn1(out)                              
                out = torch.nn.functional.relu(out)
                if self.in_ch == self.out_ch:
                    out = self.convo2(out)                              
                    out = self.bn2(out)                              
                    out = torch.nn.functional.relu(out)
                if self.downsample:
                    out = self.downsampler(out)
                    identity = self.downsampler(identity)
                if self.skip_connections:
                    if self.in_ch == self.out_ch:
                        out += identity                              
                    else:
                        out[:,:self.in_ch,:,:] += identity
                        out[:,self.in_ch:,:,:] += identity
                return out


        class LOADnet1(nn.Module):
            """
            The acronym 'LOAD' stands for 'LOcalization And Detection'.
            LOADnet1 only uses fully-connected layers for the regression

            Class Path:   DLStudio  ->  DetectAndLocalize  ->  LOADnet1
            """
            def __init__(self, skip_connections=True, depth=32):
                super(DLStudio.DetectAndLocalize.LOADnet1, self).__init__()
                self.pool_count = 3
                self.depth = depth // 2
                self.conv = nn.Conv2d(3, 64, 3, padding=1)
#                self.pool = nn.MaxPool2d(2, 2)
                self.skip64 = DLStudio.DetectAndLocalize.SkipBlock(64, 64, 
                                                           skip_connections=skip_connections)
                self.skip64ds = DLStudio.DetectAndLocalize.SkipBlock(64, 64, 
                                           downsample=True, skip_connections=skip_connections)
                self.skip64to128 = DLStudio.DetectAndLocalize.SkipBlock(64, 128, 
                                                            skip_connections=skip_connections )
                self.skip128 = DLStudio.DetectAndLocalize.SkipBlock(128, 128, 
                                                             skip_connections=skip_connections)
                self.skip128ds = DLStudio.DetectAndLocalize.SkipBlock(128,128,
                                            downsample=True, skip_connections=skip_connections)
                self.fc1 =  nn.Linear(128 * (32 // 2**self.pool_count)**2, 1000)
                self.fc2 =  nn.Linear(1000, 5)
                self.fc3 =  nn.Linear(32768, 1000)
                self.fc4 =  nn.Linear(1000, 4)

            def forward(self, x):
#                x = self.pool(torch.nn.functional.relu(self.conv(x)))          
                x = nn.MaxPool2d(2,2)(torch.nn.functional.relu(self.conv(x)))          
                ## The labeling section:
                for _ in range(self.depth // 4):
                    x1 = self.skip64(x)                                               
                x1 = self.skip64ds(x1)
                for _ in range(self.depth // 4):
                    x1 = self.skip64(x1)                                               
                x1 = self.skip64to128(x1)
                for _ in range(self.depth // 4):
                    x1 = self.skip128(x1)                                               
                x1 = self.skip128ds(x1)                                               
                for _ in range(self.depth // 4):
                    x1 = self.skip128(x1)                                               
                x1 = x1.view(-1, 128 * (32 // 2**self.pool_count)**2 )
                x1 = torch.nn.functional.relu(self.fc1(x1))
                x1 = self.fc2(x1)
                ## The Bounding Box regression:
                x2 = x.view(-1, 32768 )
                x2 = torch.nn.functional.relu(self.fc3(x2))
                x2 = self.fc4(x2)
                return x1,x2

        class LOADnet2(nn.Module):
            """
            The acronym 'LOAD' stands for 'LOcalization And Detection'.
            LOADnet2 uses both convo and linear layers for regression

            Class Path:   DLStudio  ->  DetectAndLocalize  ->  LOADnet2
            """ 
            def __init__(self, skip_connections=True, depth=8):
                super(DLStudio.DetectAndLocalize.LOADnet2, self).__init__()
                if depth not in [8,10,12,14,16]:
                    sys.exit("LOADnet2 has only been tested for 'depth' values 8, 10, 12, 14, and 16")
                self.depth = depth // 2
                self.conv = nn.Conv2d(3, 64, 3, padding=1)
#                self.pool = nn.MaxPool2d(2, 2)
                self.bn1  = nn.BatchNorm2d(64)
                self.bn2  = nn.BatchNorm2d(128)
                self.skip64_arr = nn.ModuleList()
                for i in range(self.depth):
                    self.skip64_arr.append(DLStudio.DetectAndLocalize.SkipBlock(64, 64,
                                                          skip_connections=skip_connections))
                self.skip64ds = DLStudio.DetectAndLocalize.SkipBlock(64, 64, 
                                            downsample=True, skip_connections=skip_connections)
                self.skip64to128 = DLStudio.DetectAndLocalize.SkipBlock(64, 128, 
                                                            skip_connections=skip_connections )
                self.skip128_arr = nn.ModuleList()
                for i in range(self.depth):
                    self.skip128_arr.append(DLStudio.DetectAndLocalize.SkipBlock(128, 128,
                                                         skip_connections=skip_connections))
                self.skip128ds = DLStudio.DetectAndLocalize.SkipBlock(128,128,
                                            downsample=True, skip_connections=skip_connections)
                self.fc1 =  nn.Linear(2048, 1000)
                self.fc2 =  nn.Linear(1000, 5)

                ##  for regression
                self.conv_seqn = nn.Sequential(
                    nn.Conv2d(in_channels=64, out_channels=64, kernel_size=3, padding=1),
                    nn.BatchNorm2d(64),
                    nn.ReLU(inplace=True),
                    nn.Conv2d(in_channels=64, out_channels=64, kernel_size=3, padding=1),
                    nn.ReLU(inplace=True)
                )
                self.fc_seqn = nn.Sequential(
                    nn.Linear(16384, 1024),
                    nn.ReLU(inplace=True),
                    nn.Linear(1024, 512),
                    nn.ReLU(inplace=True),
                    nn.Linear(512, 4)        ## output for the 4 coords (x_min,y_min,x_max,y_max) of BBox
                )

            def forward(self, x):
                x = nn.MaxPool2d(2,2)(torch.nn.functional.relu(self.conv(x)))          
                ## The labeling section:
                x1 = x.clone()
                for i,skip64 in enumerate(self.skip64_arr[:self.depth//4]):
                    x1 = skip64(x1)                
                x1 = self.skip64ds(x1)
                for i,skip64 in enumerate(self.skip64_arr[self.depth//4:]):
                    x1 = skip64(x1)                
                x1 = self.bn1(x1)
                x1 = self.skip64to128(x1)
                for i,skip128 in enumerate(self.skip128_arr[:self.depth//4]):
                    x1 = skip128(x1)                
                x1 = self.bn2(x1)
                x1 = self.skip128ds(x1)
                for i,skip128 in enumerate(self.skip128_arr[self.depth//4:]):
                    x1 = skip128(x1)                
                x1 = x1.view(-1, 2048 )
                x1 = torch.nn.functional.relu(self.fc1(x1))
                x1 = self.fc2(x1)
                ## The Bounding Box regression:
                x2 = self.conv_seqn(x)
                # flatten
                x2 = x2.view(x.size(0), -1)
                x2 = self.fc_seqn(x2)
                return x1,x2

        class LOADnet3(nn.Module):
            """
            The acronym 'LOAD' stands for 'LOcalization And Detection'.
            LOADnet3 uses both convo and linear layers for regression

            Class Path:   DLStudio  ->  DetectAndLocalize  ->  LOADnet3
            """ 
            def __init__(self, skip_connections=True, depth=8):
                super(DLStudio.DetectAndLocalize.LOADnet3, self).__init__()
                if depth not in [4, 8, 16]:
                    sys.exit("LOADnet2 has been tested for 'depth' for only 4, 8, and 16")
                self.depth = depth // 4
                self.conv = nn.Conv2d(3, 64, 3, padding=1)
                self.skip64_arr = nn.ModuleList()
                for i in range(self.depth):
                    self.skip64_arr.append(DLStudio.DetectAndLocalize.SkipBlock(64, 64,
                                                          skip_connections=skip_connections))
                self.skip64ds = DLStudio.DetectAndLocalize.SkipBlock(64, 64, 
                                            downsample=True, skip_connections=skip_connections)
                self.skip64to128 = DLStudio.DetectAndLocalize.SkipBlock(64, 128, 
                                                            skip_connections=skip_connections )
                self.skip128_arr = nn.ModuleList()
                for i in range(self.depth):
                    self.skip128_arr.append(DLStudio.DetectAndLocalize.SkipBlock(128, 128,
                                                         skip_connections=skip_connections))
                self.skip128ds = DLStudio.DetectAndLocalize.SkipBlock(128,128,
                                            downsample=True, skip_connections=skip_connections)
                self.fc1 =  nn.Linear(2048, 1000)
                self.fc2 =  nn.Linear(1000, 5)

                ##  for regression
                self.conv_seqn = nn.Sequential(
                    nn.Conv2d(in_channels=64, out_channels=64, kernel_size=3, padding=1),
                    nn.ReLU(inplace=True),
                    nn.Conv2d(in_channels=64, out_channels=64, kernel_size=3, padding=1),
                    nn.ReLU(inplace=True)
                )
                self.fc_seqn = nn.Sequential(
                    nn.Linear(16384, 1024),
                    nn.ReLU(inplace=True),
                    nn.Linear(1024, 512),
                    nn.ReLU(inplace=True),
                    nn.Linear(512, 4)
                )
            def forward(self, x):
#                x = self.pool(torch.nn.functional.relu(self.conv(x)))          
                x = nn.MaxPool2d(2,2)(torch.nn.functional.relu(self.conv(x)))          
                ## The labeling section:
                x1 = x.clone()
                for i,skip64 in enumerate(self.skip64_arr[:self.depth//4]):
                    x1 = skip64(x1)                
                x1 = self.skip64ds(x1)
                for i,skip64 in enumerate(self.skip64_arr[self.depth//4:]):
                    x1 = skip64(x1)                
                x1 = self.skip64ds(x1)
                x1 = self.skip64to128(x1)
                for i,skip128 in enumerate(self.skip128_arr[:self.depth//4]):
                    x1 = skip128(x1)                
                for i,skip128 in enumerate(self.skip128_arr[self.depth//4:]):
                    x1 = skip128(x1)                
                x1 = x1.view(-1, 2048 )
                x1 = torch.nn.functional.relu(self.fc1(x1))
                x1 = self.fc2(x1)
                ## The Bounding Box regression:
                for _ in range(4):
                    x2 = self.skip64(x)                                               
                x2 = self.skip64to128(x2)
                for _ in range(4):
                    x2 = self.skip128(x2)                                               
                x2 = x.view(-1, 128 * (32 // 2**self.pool_count)**2 )
                x2 = torch.nn.functional.relu(self.fc3(x2))
                x2 = self.fc4(x2)
                return x1,x2

        class IOULoss(nn.Module):
            """
            Class Path:   DLStudio  ->  DetectAndLocalize  ->  IOULoss
            """
            def __init__(self, batch_size):
                super(DLStudio.DetectAndLocalize.IOULoss, self).__init__()
                self.batch_size = batch_size
            def forward(self, input, target):
                composite_loss = []
                for idx in range(self.batch_size):
                    union = intersection = 0.0
                    for i in range(32):
                        for j in range(32):
                            inp = input[idx,i,j]
                            tap = target[idx,i,j]
                            if (inp == tap) and (inp==1):
                                intersection += 1
                                union += 1
                            elif (inp != tap) and ((inp==1) or (tap==1)):
                                union += 1
                    if union == 0.0:
                        raise Exception("something_wrong")
                    batch_sample_iou = intersection / float(union)
                    composite_loss.append(batch_sample_iou)
                total_iou_for_batch = sum(composite_loss) 
                return 1 - torch.tensor([total_iou_for_batch / self.batch_size])


        def run_code_for_training_with_CrossEntropy_and_MSE_Losses(self, net):        
            filename_for_out1 = "performance_numbers_" + str(self.dl_studio.epochs) + "label.txt"
            filename_for_out2 = "performance_numbers_" + str(self.dl_studio.epochs) + "regres.txt"
            FILE1 = open(filename_for_out1, 'w')
            FILE2 = open(filename_for_out2, 'w')
            net = copy.deepcopy(net)
            net = net.to(self.dl_studio.device)
            criterion1 = nn.CrossEntropyLoss()
            criterion2 = nn.MSELoss()
            optimizer = optim.SGD(net.parameters(), lr=self.dl_studio.learning_rate, momentum=self.dl_studio.momentum)
            print("\n\nStarting training loop...\n\n")
            start_time = time.perf_counter()
            labeling_loss_tally = []   
            regression_loss_tally = [] 
            elapsed_time = 0.0   
            for epoch in range(self.dl_studio.epochs):  
                print("")
                running_loss_labeling = 0.0
                running_loss_regression = 0.0       
                for i, data in enumerate(self.train_dataloader):
                    gt_too_small = False
                    inputs, bbox_gt, labels = data['image'], data['bbox'], data['label']
                    if i % 500 == 499:
                        current_time = time.perf_counter()
                        elapsed_time = current_time - start_time
                        print("\n\n\n[epoch:%d/%d  iter=%4d  elapsed_time=%5d secs]      Ground Truth:     " % 
                                 (epoch+1, self.dl_studio.epochs, i+1, elapsed_time) 
                               + ' '.join('%10s' % self.dataserver_train.class_labels[labels[j].item()] 
                                                                for j in range(self.dl_studio.batch_size)))
                    inputs = inputs.to(self.dl_studio.device)
                    labels = labels.to(self.dl_studio.device)
                    bbox_gt = bbox_gt.to(self.dl_studio.device)
                    optimizer.zero_grad()
                    if self.debug:
                        self.dl_studio.display_tensor_as_image(
                          torchvision.utils.make_grid(inputs.cpu(), nrow=4, normalize=True, padding=2, pad_value=10))
                    outputs = net(inputs)
                    outputs_label = outputs[0]
                    bbox_pred = outputs[1]
                    if i % 500 == 499:
                        inputs_copy = inputs.detach().clone()
                        inputs_copy = inputs_copy.cpu()
                        bbox_pc = bbox_pred.detach().clone()
                        bbox_pc[bbox_pc<0] = 0
                        bbox_pc[bbox_pc>31] = 31
                        bbox_pc[torch.isnan(bbox_pc)] = 0
                        _, predicted = torch.max(outputs_label.data, 1)
                        print("[epoch:%d/%d  iter=%4d  elapsed_time=%5d secs]  Predicted Labels:     " % 
                                (epoch+1, self.dl_studio.epochs, i+1, elapsed_time)  
                              + ' '.join('%10s' % self.dataserver_train.class_labels[predicted[j].item()] 
                                                                 for j in range(self.dl_studio.batch_size)))
                        for idx in range(self.dl_studio.batch_size):
                            i1 = int(bbox_gt[idx][1])
                            i2 = int(bbox_gt[idx][3])
                            j1 = int(bbox_gt[idx][0])
                            j2 = int(bbox_gt[idx][2])
                            k1 = int(bbox_pc[idx][1])
                            k2 = int(bbox_pc[idx][3])
                            l1 = int(bbox_pc[idx][0])
                            l2 = int(bbox_pc[idx][2])
                            print("                    gt_bb:  [%d,%d,%d,%d]"%(j1,i1,j2,i2))
                            print("                  pred_bb:  [%d,%d,%d,%d]"%(l1,k1,l2,k2))
                            inputs_copy[idx,0,i1:i2,j1] = 255
                            inputs_copy[idx,0,i1:i2,j2] = 255
                            inputs_copy[idx,0,i1,j1:j2] = 255
                            inputs_copy[idx,0,i2,j1:j2] = 255
                            inputs_copy[idx,2,k1:k2,l1] = 255                      
                            inputs_copy[idx,2,k1:k2,l2] = 255
                            inputs_copy[idx,2,k1,l1:l2] = 255
                            inputs_copy[idx,2,k2,l1:l2] = 255
                    loss_labeling = criterion1(outputs_label, labels)
                    loss_labeling.backward(retain_graph=True)        
                    loss_regression = criterion2(bbox_pred, bbox_gt)
                    loss_regression.backward()
                    optimizer.step()
                    running_loss_labeling += loss_labeling.item()    
                    running_loss_regression += loss_regression.item()                
                    if i % 500 == 499:    
                        avg_loss_labeling = running_loss_labeling / float(500)
                        avg_loss_regression = running_loss_regression / float(500)
                        labeling_loss_tally.append(avg_loss_labeling)  
                        regression_loss_tally.append(avg_loss_regression)    
                        print("[epoch:%d/%d  iter=%4d  elapsed_time=%5d secs]       loss_labeling %.3f        loss_regression: %.3f " %  (epoch+1, self.dl_studio.epochs, i+1, elapsed_time, avg_loss_labeling, avg_loss_regression))
                        FILE1.write("%.3f\n" % avg_loss_labeling)
                        FILE1.flush()
                        FILE2.write("%.3f\n" % avg_loss_regression)
                        FILE2.flush()
                        running_loss_labeling = 0.0
                        running_loss_regression = 0.0
                    if i%500==499:
                        logger = logging.getLogger()
                        old_level = logger.level
                        logger.setLevel(100)
                        plt.figure(figsize=[8,3])
                        plt.imshow(np.transpose(torchvision.utils.make_grid(inputs_copy, normalize=True,
                                                                         padding=3, pad_value=255).cpu(), (1,2,0)))
                        plt.show()
                        logger.setLevel(old_level)
            print("\nFinished Training\n")
            self.save_model(net)
            plt.figure(figsize=(10,5))
            plt.title("Labeling Loss vs. Iterations")
            plt.plot(labeling_loss_tally)
            plt.xlabel("iterations")
            plt.ylabel("labeling loss")
            plt.legend()
            plt.savefig("labeling_loss.png")
            plt.show()
            plt.title("regression Loss vs. Iterations")
            plt.plot(regression_loss_tally)
            plt.xlabel("iterations")
            plt.ylabel("regression loss")
            plt.legend()
            plt.savefig("regression_loss.png")
            plt.show()


        def save_model(self, model):
            '''
            Save the trained model to a disk file
            '''
            torch.save(model.state_dict(), self.dl_studio.path_saved_model)


        def run_code_for_testing_detection_and_localization(self, net):
            net.load_state_dict(torch.load(self.dl_studio.path_saved_model))
            correct = 0
            total = 0
            confusion_matrix = torch.zeros(len(self.dataserver_train.class_labels), 
                                           len(self.dataserver_train.class_labels))
            class_correct = [0] * len(self.dataserver_train.class_labels)
            class_total = [0] * len(self.dataserver_train.class_labels)
            with torch.no_grad():
                for i, data in enumerate(self.test_dataloader):
                    images, bounding_box, labels = data['image'], data['bbox'], data['label']
                    labels = labels.tolist()
                    if self.dl_studio.debug_test and i % 50 == 0:
                        print("\n\n[i=%d:] Ground Truth:     " %i + ' '.join('%10s' % 
                         self.dataserver_train.class_labels[labels[j]] for j in range(self.dl_studio.batch_size)))
                    outputs = net(images)
                    outputs_label = outputs[0]
                    outputs_regression = outputs[1]
                    outputs_regression[outputs_regression < 0] = 0
                    outputs_regression[outputs_regression > 31] = 31
                    outputs_regression[torch.isnan(outputs_regression)] = 0
                    output_bb = outputs_regression.tolist()
                    _, predicted = torch.max(outputs_label.data, 1)
                    predicted = predicted.tolist()
                    if self.dl_studio.debug_test and i % 50 == 0:
                        print("[i=%d:] Predicted Labels: " %i + ' '.join('%10s' % 
                              self.dataserver_train.class_labels[predicted[j]] for j in range(self.dl_studio.batch_size)))
                        for idx in range(self.dl_studio.batch_size):
                            i1 = int(bounding_box[idx][1])
                            i2 = int(bounding_box[idx][3])
                            j1 = int(bounding_box[idx][0])
                            j2 = int(bounding_box[idx][2])
                            k1 = int(output_bb[idx][1])
                            k2 = int(output_bb[idx][3])
                            l1 = int(output_bb[idx][0])
                            l2 = int(output_bb[idx][2])
                            print("                    gt_bb:  [%d,%d,%d,%d]"%(j1,i1,j2,i2))
                            print("                  pred_bb:  [%d,%d,%d,%d]"%(l1,k1,l2,k2))
                            images[idx,0,i1:i2,j1] = 255
                            images[idx,0,i1:i2,j2] = 255
                            images[idx,0,i1,j1:j2] = 255
                            images[idx,0,i2,j1:j2] = 255
                            images[idx,2,k1:k2,l1] = 255                      
                            images[idx,2,k1:k2,l2] = 255
                            images[idx,2,k1,l1:l2] = 255
                            images[idx,2,k2,l1:l2] = 255
                        logger = logging.getLogger()
                        old_level = logger.level
                        logger.setLevel(100)
                        plt.figure(figsize=[8,3])
                        plt.imshow(np.transpose(torchvision.utils.make_grid(images, normalize=True,
                                                                         padding=3, pad_value=255).cpu(), (1,2,0)))
                        plt.show()
                        logger.setLevel(old_level)
                    for label,prediction in zip(labels,predicted):
                        confusion_matrix[label][prediction] += 1
                    total += len(labels)
                    correct +=  [predicted[ele] == labels[ele] for ele in range(len(predicted))].count(True)
                    comp = [predicted[ele] == labels[ele] for ele in range(len(predicted))]
                    for j in range(self.dl_studio.batch_size):
                        label = labels[j]
                        class_correct[label] += comp[j]
                        class_total[label] += 1
            print("\n")
            for j in range(len(self.dataserver_train.class_labels)):
                print('Prediction accuracy for %5s : %2d %%' % (
              self.dataserver_train.class_labels[j], 100 * class_correct[j] / class_total[j]))
            print("\n\n\nOverall accuracy of the network on the 1000 test images: %d %%" % 
                                                                   (100 * correct / float(total)))
            print("\n\nDisplaying the confusion matrix:\n")
            out_str = "                "
            for j in range(len(self.dataserver_train.class_labels)):  
                                 out_str +=  "%15s" % self.dataserver_train.class_labels[j]   
            print(out_str + "\n")
            for i,label in enumerate(self.dataserver_train.class_labels):
                out_percents = [100 * confusion_matrix[i,j] / float(class_total[i]) 
                                 for j in range(len(self.dataserver_train.class_labels))]
                out_percents = ["%.2f" % item.item() for item in out_percents]
                out_str = "%12s:  " % self.dataserver_train.class_labels[i]
                for j in range(len(self.dataserver_train.class_labels)): 
                                                       out_str +=  "%15s" % out_percents[j]
                print(out_str)


    ###%%%
    ########################################################################################
    ##################  Start Definition of Inner Class SemanticSegmentation  ##############

    class SemanticSegmentation(nn.Module):             
        """The purpose of this inner class is to be able to use the DLStudio module for
           experiments with semantic segmentation.  At its simplest level, the
           purpose of semantic segmentation is to assign correct labels to the
           different objects in a scene, while localizing them at the same time.  At
           a more sophisticated level, a system that carries out semantic
           segmentation should also output a symbolic expression based on the objects
           found in the image and their spatial relationships with one another.

           The workhorse of this inner class is the mUnet network that is based
           on the UNET network that was first proposed by Ronneberger, Fischer and
           Brox in the paper "U-Net: Convolutional Networks for Biomedical Image
           Segmentation".  Their Unet extracts binary masks for the cell pixel blobs
           of interest in biomedical images.  The output of their Unet can
           therefore be treated as a pixel-wise binary classifier at each pixel
           position.  The mUnet class, on the other hand, is intended for
           segmenting out multiple objects simultaneously form an image. [A weaker
           reason for "Multi" in the name of the class is that it uses skip
           connections not only across the two arms of the "U", but also also along
           the arms.  The skip connections in the original Unet are only between the
           two arms of the U.  In mUnet, each object type is assigned a separate
           channel in the output of the network.

           This version of DLStudio also comes with a new dataset,
           PurdueShapes5MultiObject, for experimenting with mUnet.  Each image in
           this dataset contains a random number of selections from five different
           shapes, with the shapes being randomly scaled, oriented, and located in
           each image.  The five different shapes are: rectangle, triangle, disk,
           oval, and star.

           Class Path:   DLStudio  ->  SemanticSegmentation
        """
        def __init__(self, dl_studio, dataserver_train=None, dataserver_test=None, dataset_file_train=None, dataset_file_test=None):
            super(DLStudio.SemanticSegmentation, self).__init__()
            self.dl_studio = dl_studio
            self.dataserver_train = dataserver_train
            self.dataserver_test = dataserver_test

        class PurdueShapes5MultiObjectDataset(torch.utils.data.Dataset):
            """
            The very first thing to note is that the images in the dataset
            PurdueShapes5MultiObjectDataset are of size 64x64.  Each image has a
            random number (up to five) of the objects drawn from the following five
            shapes: rectangle, triangle, disk, oval, and star.  Each shape is
            randomized with respect to all its parameters, including those for its
            scale and location in the image.

            Each image in the dataset is represented by two data objects, one a list
            and the other a dictionary. The list data objects consists of the
            following items:

                [R, G, B, mask_array, mask_val_to_bbox_map]                                   ## (A)
            
            and the other data object is a dictionary that is set to:
            
                label_map = {'rectangle':50, 
                             'triangle' :100, 
                             'disk'     :150, 
                             'oval'     :200, 
                             'star'     :250}                                                 ## (B)
            
            Note that that second data object for each image is the same, as shown
            above.

            In the rest of this comment block, I'll explain in greater detail the
            elements of the list in line (A) above.

            
            R,G,B:
            ------

            Each of these is a 4096-element array whose elements store the
            corresponding color values at each of the 4096 pixels in a 64x64 image.
            That is, R is a list of 4096 integers, each between 0 and 255, for the
            value of the red component of the color at each pixel. Similarly, for G
            and B.
            

            mask_array:
            ----------

            The fourth item in the list shown in line (A) above is for the mask which is
            a numpy array of shape:
            
                           (5, 64, 64)
            
            It is initialized by the command:
            
                 mask_array = np.zeros((5,64,64), dtype=np.uint8)
            
            In essence, the mask_array consists of five planes, each of size 64x64.
            Each plane of the mask array represents an object type according to the
            following shape_index
            
                    shape_index = (label_map[shape] - 50) // 50
            
            where the label_map is as shown in line (B) above.  In other words, the
            shape_index values for the different shapes are:
            
                     rectangle:  0
                      triangle:  1
                          disk:  2
                          oval:  3
                          star:  4
            
            Therefore, the first layer (of index 0) of the mask is where the pixel
            values of 50 are stored at all those pixels that belong to the rectangle
            shapes.  Similarly, the second mask layer (of index 1) is where the pixel
            values of 100 are stored at all those pixel coordinates that belong to
            the triangle shapes in an image; and so on.
            
            It is in the manner described above that we define five different masks
            for an image in the dataset.  Each mask is for a different shape and the
            pixel values at the nonzero pixels in each mask layer are keyed to the
            shapes also.
            
            A reader is likely to wonder as to the need for this redundancy in the
            dataset representation of the shapes in each image.  Such a reader is
            likely to ask: Why can't we just use the binary values 1s and 0s in each
            mask layer where the corresponding pixels are in the image?  Setting
            these mask values to 50, 100, etc., was done merely for convenience.  I
            went with the intuition that the learning needed for multi-object
            segmentation would become easier if each shape was represented by a
            different pixels value in the corresponding mask. So I went ahead
            incorporated that in the dataset generation program itself.

            The mask values for the shapes are not to be confused with the actual RGB
            values of the pixels that belong to the shapes. The RGB values at the
            pixels in a shape are randomly generated.  Yes, all the pixels in a shape
            instance in an image have the same RGB values (but that value has nothing
            to do with the values given to the mask pixels for that shape).
            
            
            mask_val_to_bbox_map:
            --------------------
                   
            The fifth item in the list in line (A) above is a dictionary that tells us
            what bounding-box rectangle to associate with each shape in the image.  To
            illustrate what this dictionary looks like, assume that an image contains
            only one rectangle and only one disk, the dictionary in this case will look
            like:
            
                mask values to bbox mappings:  {200: [], 
                                                250: [], 
                                                100: [], 
                                                 50: [[56, 20, 63, 25]], 
                                                150: [[37, 41, 55, 59]]}
            
            Should there happen to be two rectangles in the same image, the dictionary
            would then be like:
            
                mask values to bbox mappings:  {200: [], 
                                                250: [], 
                                                100: [], 
                                                 50: [[56, 20, 63, 25], [18, 16, 32, 36]], 
                                                150: [[37, 41, 55, 59]]}
            
            Therefore, it is not a problem even if all the objects in an image are of
            the same type.  Remember, the object that are selected for an image are
            shown randomly from the different shapes.  By the way, an entry like '[56,
            20, 63, 25]' for the bounding box means that the upper-left corner of the
            BBox for the 'rectangle' shape is at (56,20) and the lower-right corner of
            the same is at the pixel coordinates (63,25).
            
            As far as the BBox quadruples are concerned, in the definition
            
                    [min_x,min_y,max_x,max_y]
            
            note that x is the horizontal coordinate, increasing to the right on your
            screen, and y is the vertical coordinate increasing downwards.

            Class Path:   DLStudio  ->  SemanticSegmentation  ->  PurdueShapes5MultiObjectDataset
            """
            def __init__(self, dl_studio, train_or_test, dataset_file):
                super(DLStudio.SemanticSegmentation.PurdueShapes5MultiObjectDataset, self).__init__()
                if train_or_test == 'train' and dataset_file == "PurdueShapes5MultiObject-10000-train.gz":
                    if os.path.exists("torch_saved_PurdueShapes5MultiObject-10000_dataset.pt") and \
                              os.path.exists("torch_saved_PurdueShapes5MultiObject_label_map.pt"):
                        print("\nLoading training data from torch saved file")
                        self.dataset = torch.load("torch_saved_PurdueShapes5MultiObject-10000_dataset.pt")
                        self.label_map = torch.load("torch_saved_PurdueShapes5MultiObject_label_map.pt")
                    else: 
                        print("""\n\n\nLooks like this is the first time you will be loading in\n"""
                              """the dataset for this script. First time loading could take\n"""
                              """up to 3 minutes.  Any subsequent attempts will only take\n"""
                              """a few seconds.\n\n\n""")
                        root_dir = dl_studio.dataroot
                        f = gzip.open(root_dir + dataset_file, 'rb')
                        dataset = f.read()
                        self.dataset, self.label_map = pickle.loads(dataset, encoding='latin1')
                        torch.save(self.dataset, "torch_saved_PurdueShapes5MultiObject-10000_dataset.pt")
                        torch.save(self.label_map, "torch_saved_PurdueShapes5MultiObject_label_map.pt")
                        # reverse the key-value pairs in the label dictionary:
                        self.class_labels = dict(map(reversed, self.label_map.items()))
                else:
                    root_dir = dl_studio.dataroot
                    f = gzip.open(root_dir + dataset_file, 'rb')
                    dataset = f.read()
                    if sys.version_info[0] == 3:
                        self.dataset, self.label_map = pickle.loads(dataset, encoding='latin1')
                    else:
                        self.dataset, self.label_map = pickle.loads(dataset)
                    # reverse the key-value pairs in the label dictionary:
                    self.class_labels = dict(map(reversed, self.label_map.items()))

            def __len__(self):
                return len(self.dataset)

            def __getitem__(self, idx):
                r = np.array( self.dataset[idx][0] )
                g = np.array( self.dataset[idx][1] )
                b = np.array( self.dataset[idx][2] )
                R,G,B = r.reshape(64,64), g.reshape(64,64), b.reshape(64,64)
                im_tensor = torch.zeros(3,64,64, dtype=torch.float)
                im_tensor[0,:,:] = torch.from_numpy(R)
                im_tensor[1,:,:] = torch.from_numpy(G)
                im_tensor[2,:,:] = torch.from_numpy(B)
#                mask_array = self.dataset[idx][3]
                mask_array = np.array(self.dataset[idx][3])
                mask_tensor = torch.from_numpy(mask_array)
                mask_val_to_bbox_map =  self.dataset[idx][4]
                max_bboxes_per_entry_in_map = max([ len(mask_val_to_bbox_map[key]) for key in mask_val_to_bbox_map ])
                ##  The first arg 5 is for the number of bboxes we are going to need. If all the
                ##  shapes are exactly the same, you are going to need five different bbox'es.
                ##  The second arg is the index reserved for each shape in a single bbox
                bbox_tensor = torch.zeros(5,5,4, dtype=torch.float)
                for bbox_idx in range(max_bboxes_per_entry_in_map):
                    for key in mask_val_to_bbox_map:
                        if len(mask_val_to_bbox_map[key]) == 1:
                            if bbox_idx == 0:
                                bbox_tensor[bbox_idx,key,:] = torch.from_numpy(np.array(mask_val_to_bbox_map[key][bbox_idx]))
                        elif len(mask_val_to_bbox_map[key]) > 1 and bbox_idx < len(mask_val_to_bbox_map[key]):
                            bbox_tensor[bbox_idx,key,:] = torch.from_numpy(np.array(mask_val_to_bbox_map[key][bbox_idx]))
                sample = {'image'        : im_tensor, 
                          'mask_tensor'  : mask_tensor,
                          'bbox_tensor'  : bbox_tensor }
                return sample

        def load_PurdueShapes5MultiObject_dataset(self, dataserver_train, dataserver_test ):   
            self.train_dataloader = torch.utils.data.DataLoader(dataserver_train,
                        batch_size=self.dl_studio.batch_size,shuffle=True, num_workers=4)
            self.test_dataloader = torch.utils.data.DataLoader(dataserver_test,
                               batch_size=self.dl_studio.batch_size,shuffle=False, num_workers=4)

        class SkipBlockDN(nn.Module):
            """
            This class for the skip connections in the downward leg of the "U"

            Class Path:   DLStudio  ->  SemanticSegmentation  ->  SkipBlockDN
            """
            def __init__(self, in_ch, out_ch, downsample=False, skip_connections=True):
                super(DLStudio.SemanticSegmentation.SkipBlockDN, self).__init__()
                self.downsample = downsample
                self.skip_connections = skip_connections
                self.in_ch = in_ch
                self.out_ch = out_ch
                self.convo1 = nn.Conv2d(in_ch, out_ch, 3, stride=1, padding=1)
                self.convo2 = nn.Conv2d(in_ch, out_ch, 3, stride=1, padding=1)
                self.bn1 = nn.BatchNorm2d(out_ch)
                self.bn2 = nn.BatchNorm2d(out_ch)
                if downsample:
                    self.downsampler = nn.Conv2d(in_ch, out_ch, 1, stride=2)
            def forward(self, x):
                identity = x                                     
                out = self.convo1(x)                              
                out = self.bn1(out)                              
                out = torch.nn.functional.relu(out)
                if self.in_ch == self.out_ch:
                    out = self.convo2(out)                              
                    out = self.bn2(out)                              
                    out = torch.nn.functional.relu(out)
                if self.downsample:
                    out = self.downsampler(out)
                    identity = self.downsampler(identity)
                if self.skip_connections:
                    if self.in_ch == self.out_ch:
                        out += identity                              
                    else:
                        out[:,:self.in_ch,:,:] += identity
                        out[:,self.in_ch:,:,:] += identity
                return out

        class SkipBlockUP(nn.Module):
            """
            This class is for the skip connections in the upward leg of the "U"

            Class Path:   DLStudio  ->  SemanticSegmentation  ->  SkipBlockUP
            """
            def __init__(self, in_ch, out_ch, upsample=False, skip_connections=True):
                super(DLStudio.SemanticSegmentation.SkipBlockUP, self).__init__()
                self.upsample = upsample
                self.skip_connections = skip_connections
                self.in_ch = in_ch
                self.out_ch = out_ch
                self.convoT1 = nn.ConvTranspose2d(in_ch, out_ch, 3, padding=1)
                self.convoT2 = nn.ConvTranspose2d(in_ch, out_ch, 3, padding=1)
                self.bn1 = nn.BatchNorm2d(out_ch)
                self.bn2 = nn.BatchNorm2d(out_ch)
                if upsample:
                    self.upsampler = nn.ConvTranspose2d(in_ch, out_ch, 1, stride=2, dilation=2, output_padding=1, padding=0)

            def forward(self, x):
                identity = x                                     
                out = self.convoT1(x)                              
                out = self.bn1(out)                              
                out = torch.nn.functional.relu(out)
                if self.in_ch == self.out_ch:
                    out = self.convoT2(out)                              
                    out = self.bn2(out)                              
                    out = torch.nn.functional.relu(out)
                if self.upsample:
                    out = self.upsampler(out)
                    identity = self.upsampler(identity)
                if self.skip_connections:
                    if self.in_ch == self.out_ch:
                        out += identity                              
                    else:
                        out += identity[:,self.out_ch:,:,:]
                return out

        class mUnet(nn.Module):
            """
            This network is called mUnet because it is intended for segmenting
            out multiple objects simultaneously form an image. [A weaker reason for
            "Multi" in the name of the class is that it uses skip connections not
            only across the two arms of the "U", but also also along the arms.]  The
            classic UNET was first proposed by Ronneberger, Fischer and Brox in the
            paper "U-Net: Convolutional Networks for Biomedical Image Segmentation".
            Their UNET extracts binary masks for the cell pixel blobs of interest
            in biomedical images.  The output of their UNET therefore can therefore
            be treated as a pixel-wise binary classifier at each pixel position.  

            The mUnet presented here, on the other hand, is meant specifically
            for simultaneously identifying and localizing multiple objects in a
            given image.  Each object type is assigned a separate channel in the
            output of the network.  

            I have created a dataset, PurdueShapes5MultiObject, for experimenting
            with mUnet.  Each image in this dataset contains a random number of
            selections from five different shapes, with the shapes being randomly
            scaled, oriented, and located in each image.  The five different shapes
            are: rectangle, triangle, disk, oval, and star.

            Class Path:   DLStudio  ->  SemanticSegmentation  ->  mUnet
            """ 
            def __init__(self, skip_connections=True, depth=16):
                super(DLStudio.SemanticSegmentation.mUnet, self).__init__()
                self.depth = depth // 2
                self.conv_in = nn.Conv2d(3, 64, 3, padding=1)
#                self.pool = nn.MaxPool2d(2, 2)
                ##  For the DN arm of the U:
                self.bn1DN  = nn.BatchNorm2d(64)
                self.bn2DN  = nn.BatchNorm2d(128)
                self.skip64DN_arr = nn.ModuleList()
                for i in range(self.depth):
                    self.skip64DN_arr.append(DLStudio.SemanticSegmentation.SkipBlockDN(64, 64,
                                                          skip_connections=skip_connections))
                self.skip64dsDN = DLStudio.SemanticSegmentation.SkipBlockDN(64, 64, 
                                           downsample=True, skip_connections=skip_connections)
                self.skip64to128DN = DLStudio.SemanticSegmentation.SkipBlockDN(64, 128, 
                                                            skip_connections=skip_connections )
                self.skip128DN_arr = nn.ModuleList()
                for i in range(self.depth):
                    self.skip128DN_arr.append(DLStudio.SemanticSegmentation.SkipBlockDN(128, 128,
                                                         skip_connections=skip_connections))
                self.skip128dsDN = DLStudio.SemanticSegmentation.SkipBlockDN(128,128,
                                            downsample=True, skip_connections=skip_connections)

                ##  For the UP arm of the U:
                self.bn1UP  = nn.BatchNorm2d(128)
                self.bn2UP  = nn.BatchNorm2d(64)
                self.skip64UP_arr = nn.ModuleList()
                for i in range(self.depth):
                    self.skip64UP_arr.append(DLStudio.SemanticSegmentation.SkipBlockUP(64, 64,
                                                          skip_connections=skip_connections))
                self.skip64usUP = DLStudio.SemanticSegmentation.SkipBlockUP(64, 64, 
                                           upsample=True, skip_connections=skip_connections)
                self.skip128to64UP = DLStudio.SemanticSegmentation.SkipBlockUP(128, 64, 
                                                            skip_connections=skip_connections )
                self.skip128UP_arr = nn.ModuleList()
                for i in range(self.depth):
                    self.skip128UP_arr.append(DLStudio.SemanticSegmentation.SkipBlockUP(128, 128,
                                                          skip_connections=skip_connections))
                self.skip128usUP = DLStudio.SemanticSegmentation.SkipBlockUP(128,128,
                                            upsample=True, skip_connections=skip_connections)
                self.conv_out = nn.ConvTranspose2d(64, 5, 3, stride=2,dilation=2,output_padding=1,padding=2)

            def forward(self, x):
                ##  Going down to the bottom of the U:
#                x = self.pool(torch.nn.functional.relu(self.conv_in(x)))          
                x = nn.MaxPool2d(2,2)(torch.nn.functional.relu(self.conv_in(x)))          
                for i,skip64 in enumerate(self.skip64DN_arr[:self.depth//4]):
                    x = skip64(x)                
                num_channels_to_save1 = x.shape[1] // 2
                save_for_upside_1 = x[:,:num_channels_to_save1,:,:].clone()
                x = self.skip64dsDN(x)
                for i,skip64 in enumerate(self.skip64DN_arr[self.depth//4:]):
                    x = skip64(x)                
                x = self.bn1DN(x)
                num_channels_to_save2 = x.shape[1] // 2
                save_for_upside_2 = x[:,:num_channels_to_save2,:,:].clone()
                x = self.skip64to128DN(x)
                for i,skip128 in enumerate(self.skip128DN_arr[:self.depth//4]):
                    x = skip128(x)                
                x = self.bn2DN(x)
                num_channels_to_save3 = x.shape[1] // 2
                save_for_upside_3 = x[:,:num_channels_to_save3,:,:].clone()
                for i,skip128 in enumerate(self.skip128DN_arr[self.depth//4:]):
                    x = skip128(x)                
                x = self.skip128dsDN(x)

                ## Coming up from the bottom of U on the other side:
                x = self.skip128usUP(x)          
                for i,skip128 in enumerate(self.skip128UP_arr[:self.depth//4]):
                    x = skip128(x)                
                x[:,:num_channels_to_save3,:,:] =  save_for_upside_3
                x = self.bn1UP(x)
                for i,skip128 in enumerate(self.skip128UP_arr[:self.depth//4]):
                    x = skip128(x)                
                x = self.skip128to64UP(x)
                for i,skip64 in enumerate(self.skip64UP_arr[self.depth//4:]):
                    x = skip64(x)                
                x[:,:num_channels_to_save2,:,:] =  save_for_upside_2
                x = self.bn2UP(x)
                x = self.skip64usUP(x)
                for i,skip64 in enumerate(self.skip64UP_arr[:self.depth//4]):
                    x = skip64(x)                
                x[:,:num_channels_to_save1,:,:] =  save_for_upside_1
                x = self.conv_out(x)
                return x

        class SegmentationLoss(nn.Module):
            """
            I wrote this class before I switched to MSE loss.  I am leaving it here
            in case I need to get back to it in the future.  

            Class Path:   DLStudio  ->  SemanticSegmentation  ->  SegmentationLoss
            """
            def __init__(self, batch_size):
                super(DLStudio.SemanticSegmentation.SegmentationLoss, self).__init__()
                self.batch_size = batch_size
            def forward(self, output, mask_tensor):
                composite_loss = torch.zeros(1,self.batch_size)
                mask_based_loss = torch.zeros(1,5)
                for idx in range(self.batch_size):
                    outputh = output[idx,0,:,:]
                    for mask_layer_idx in range(mask_tensor.shape[0]):
                        mask = mask_tensor[idx,mask_layer_idx,:,:]
                        element_wise = (outputh - mask)**2                   
                        mask_based_loss[0,mask_layer_idx] = torch.mean(element_wise)
                    composite_loss[0,idx] = torch.sum(mask_based_loss)
                return torch.sum(composite_loss) / self.batch_size

        def run_code_for_training_for_semantic_segmentation(self, net):        
            filename_for_out1 = "performance_numbers_" + str(self.dl_studio.epochs) + ".txt"
            FILE1 = open(filename_for_out1, 'w')
            net = copy.deepcopy(net)
            net = net.to(self.dl_studio.device)
            criterion1 = nn.MSELoss()
            optimizer = optim.SGD(net.parameters(), 
                         lr=self.dl_studio.learning_rate, momentum=self.dl_studio.momentum)
            start_time = time.perf_counter()
            for epoch in range(self.dl_studio.epochs):  
                print("")
                running_loss_segmentation = 0.0
                for i, data in enumerate(self.train_dataloader):    
                    im_tensor,mask_tensor,bbox_tensor =data['image'],data['mask_tensor'],data['bbox_tensor']
                    im_tensor   = im_tensor.to(self.dl_studio.device)
                    mask_tensor = mask_tensor.type(torch.FloatTensor)
                    mask_tensor = mask_tensor.to(self.dl_studio.device)                 
                    bbox_tensor = bbox_tensor.to(self.dl_studio.device)
                    optimizer.zero_grad()
                    output = net(im_tensor) 
                    segmentation_loss = criterion1(output, mask_tensor)  
                    segmentation_loss.backward()
                    optimizer.step()
                    running_loss_segmentation += segmentation_loss.item()    
                    if i%500==499:    
                        current_time = time.perf_counter()
                        elapsed_time = current_time - start_time
                        avg_loss_segmentation = running_loss_segmentation / float(500)
                        print("[epoch=%d/%d, iter=%4d  elapsed_time=%3d secs]   MSE loss: %.3f" % (epoch+1, self.dl_studio.epochs, i+1, elapsed_time, avg_loss_segmentation))
                        FILE1.write("%.3f\n" % avg_loss_segmentation)
                        FILE1.flush()
                        running_loss_segmentation = 0.0
            print("\nFinished Training\n")
            self.save_model(net)

        def save_model(self, model):
            '''
            Save the trained model to a disk file
            '''
            torch.save(model.state_dict(), self.dl_studio.path_saved_model)

        def run_code_for_testing_semantic_segmentation(self, net):
            net.load_state_dict(torch.load(self.dl_studio.path_saved_model))
            with torch.no_grad():
                for i, data in enumerate(self.test_dataloader):
                    im_tensor,mask_tensor,bbox_tensor =data['image'],data['mask_tensor'],data['bbox_tensor']
                    if self.dl_studio.debug_test and i % 50 == 0:
                        print("\n\n\n\nShowing output for test batch %d: " % (i+1))
                        outputs = net(im_tensor)                        
                        ## In the statement below: 1st arg for batch items, 2nd for channels, 
                        ##                         3rd and 4th for image size
                        output_bw_tensor = torch.zeros(4,1,64,64, dtype=float)
                        for image_idx in range(self.dl_studio.batch_size):
                            for layer_idx in range(5):
                                for m in range(64):
                                    for n in range(64):
                                        output_bw_tensor[image_idx,0,m,n]  =  \
                                                  torch.max( outputs[image_idx,:,m,n] )
#                        display_tensor = torch.zeros(8,3,64,64, dtype=float)
                        display_tensor = torch.zeros(28,3,64,64, dtype=float)
                        for idx in range(self.dl_studio.batch_size):
                            for bbox_idx in range(5):         ## 5 for the five different types of obj
                                bb_tensor = bbox_tensor[idx,bbox_idx]
                                for k in range(5):
                                    i1 = int(bb_tensor[k][1])
                                    i2 = int(bb_tensor[k][3])
                                    j1 = int(bb_tensor[k][0])
                                    j2 = int(bb_tensor[k][2])
                                    output_bw_tensor[idx,0,i1:i2,j1] = 255
                                    output_bw_tensor[idx,0,i1:i2,j2] = 255
                                    output_bw_tensor[idx,0,i1,j1:j2] = 255
                                    output_bw_tensor[idx,0,i2,j1:j2] = 255
                                    im_tensor[idx,0,i1:i2,j1] = 255
                                    im_tensor[idx,0,i1:i2,j2] = 255
                                    im_tensor[idx,0,i1,j1:j2] = 255
                                    im_tensor[idx,0,i2,j1:j2] = 255
                        display_tensor[:4,:,:,:] = output_bw_tensor
                        display_tensor[4:8,:,:,:] = im_tensor

                        for batch_im_idx in range(self.dl_studio.batch_size):
                            for mask_layer_idx in range(5):
                                for i in range(64):
                                    for j in range(64):
                                        if mask_layer_idx == 0:
                                            if 25 < outputs[batch_im_idx,mask_layer_idx,i,j] < 85:
                                                outputs[batch_im_idx,mask_layer_idx,i,j] = 255
                                            else:
                                                outputs[batch_im_idx,mask_layer_idx,i,j] = 50
                                        elif mask_layer_idx == 1:
                                            if 65 < outputs[batch_im_idx,mask_layer_idx,i,j] < 135:
                                                outputs[batch_im_idx,mask_layer_idx,i,j] = 255
                                            else:
                                                outputs[batch_im_idx,mask_layer_idx,i,j] = 50
                                        elif mask_layer_idx == 2:
                                            if 115 < outputs[batch_im_idx,mask_layer_idx,i,j] < 185:
                                                outputs[batch_im_idx,mask_layer_idx,i,j] = 255
                                            else:
                                                outputs[batch_im_idx,mask_layer_idx,i,j] = 50
                                        elif mask_layer_idx == 3:
                                            if 165 < outputs[batch_im_idx,mask_layer_idx,i,j] < 230:
                                                outputs[batch_im_idx,mask_layer_idx,i,j] = 255
                                            else:
                                                outputs[batch_im_idx,mask_layer_idx,i,j] = 50
                                        elif mask_layer_idx == 4:
                                            if outputs[batch_im_idx,mask_layer_idx,i,j] > 210:
                                                outputs[batch_im_idx,mask_layer_idx,i,j] = 255
                                            else:
                                                outputs[batch_im_idx,mask_layer_idx,i,j] = 50

                                display_tensor[8+4*mask_layer_idx+batch_im_idx,:,:,:]= \
                                                          outputs[batch_im_idx,mask_layer_idx,:,:]

                        self.dl_studio.display_tensor_as_image(
                           torchvision.utils.make_grid(display_tensor, nrow=4, normalize=True, padding=2, pad_value=10))



    ###%%%
    ########################################################################################
    ##################  Start Definition of Inner Class TextClassification  ################

    class TextClassification(nn.Module):             
        """
        The purpose of this inner class is to be able to use the DLStudio module for simple 
        experiments in text classification.  Consider, for example, the problem of automatic 
        classification of variable-length user feedback: you want to create a neural network
        that can label an uploaded product review of arbitrary length as positive or negative.  
        One way to solve this problem is with a recurrent neural network in which you use a 
        hidden state for characterizing a variable-length product review with a fixed-length 
        state vector.  This inner class allows you to carry out such experiments.

        Class Path:  DLStudio -> TextClassification 
        """
        def __init__(self, dl_studio, dataserver_train=None, dataserver_test=None, dataset_file_train=None, 
                                                               dataset_file_test=None, display_train_loss=False):
            super(DLStudio.TextClassification, self).__init__()
            self.dl_studio = dl_studio
            self.dataserver_train = dataserver_train
            self.dataserver_test = dataserver_test
            self.display_train_loss = display_train_loss

        class SentimentAnalysisDataset(torch.utils.data.Dataset):
            """
            The sentiment analysis datasets that I have made available were extracted from
            an archive of user feedback comments as made available by Amazon for the year
            2007.  The original archive contains user feedback on 25 product categories. 
            For each product category, there are two files named 'positive.reviews' and
            'negative.reviews', with each file containing 1000 reviews. I believe that
            characterizing the reviews as 'positive' or 'negative' was carried out by 
            human annotators. Regardless, the reviews in these two files can be used to 
            train a neural network whose purpose would be to automatically characterize
            a product as being positive or negative. 

            I have extracted the following datasets extracted from the Amazon archive:

                 sentiment_dataset_train_200.tar.gz        vocab_size = 43,285
                 sentiment_dataset_test_200.tar.gz  

                 sentiment_dataset_train_40.tar.gz         vocab_size = 17,001
                 sentiment_dataset_test_40.tar.gz    

                 sentiment_dataset_train_3.tar.gz          vocab_size = 3,402
                 sentiment_dataset_test_3.tar.gz    

            The integer in the name of each dataset is the number of reviews collected 
            from the 'positive.reviews' and the 'negative.reviews' files for each product
            category.  Therefore, the dataset with 200 in its name has a total of 400 
            reviews for each product category.

            As to why I am presenting these three different datasets, note that, as shown
            above, the size of the vocabulary depends on the number of reviews selected
            and the size of the vocabulary has a strong bearing on how long it takes to 
            train an algorithm for text classification. For one simple reason for that: 
            the size of the one-hot representation for the words equals the size of the 
            vocabulary.  Therefore, the one-hot representation for the words for the 
            dataset with 200 in its name will be a one-axis tensor of size 43,285.

            For a purely feedforward network, it is not a big deal for the input tensors
            to be size Nx43285 where N is the number of words in a review.  And even for
            RNNs with simple feedback, that does not slow things down.  However, when 
            using GRUs, it's an entirely different matter if you are tying to run your
            experiments on, say, a laptop with a Quadro GPU.  Hence the reason for providing
            the datasets with 200 and 40 reviews.  The dataset with just 3 reviews is for
            debugging your code.

            Class Path:  DLStudio -> TextClassification -> SentimentAnalysisDataset
            """
            def __init__(self, dl_studio, train_or_test, dataset_file):
                super(DLStudio.TextClassification.SentimentAnalysisDataset, self).__init__()
                self.train_or_test = train_or_test
                root_dir = dl_studio.dataroot
                f = gzip.open(root_dir + dataset_file, 'rb')
                dataset = f.read()
                if train_or_test == 'train':
                    if sys.version_info[0] == 3:
                        self.positive_reviews_train, self.negative_reviews_train, self.vocab = pickle.loads(dataset, encoding='latin1')
                    else:
                        self.positive_reviews_train, self.negative_reviews_train, self.vocab = pickle.loads(dataset)
                    self.categories = sorted(list(self.positive_reviews_train.keys()))
                    self.category_sizes_train_pos = {category : len(self.positive_reviews_train[category]) for category in self.categories}
                    self.category_sizes_train_neg = {category : len(self.negative_reviews_train[category]) for category in self.categories}
                    self.indexed_dataset_train = []
                    for category in self.positive_reviews_train:
                        for review in self.positive_reviews_train[category]:
                            self.indexed_dataset_train.append([review, category, 1])
                    for category in self.negative_reviews_train:
                        for review in self.negative_reviews_train[category]:
                            self.indexed_dataset_train.append([review, category, 0])
                    random.shuffle(self.indexed_dataset_train)
                elif train_or_test == 'test':
                    if sys.version_info[0] == 3:
                        self.positive_reviews_test, self.negative_reviews_test, self.vocab = pickle.loads(dataset, encoding='latin1')
                    else:
                        self.positive_reviews_test, self.negative_reviews_test, self.vocab = pickle.loads(dataset)
                    self.vocab = sorted(self.vocab)
                    self.categories = sorted(list(self.positive_reviews_test.keys()))
                    self.category_sizes_test_pos = {category : len(self.positive_reviews_test[category]) for category in self.categories}
                    self.category_sizes_test_neg = {category : len(self.negative_reviews_test[category]) for category in self.categories}
                    self.indexed_dataset_test = []
                    for category in self.positive_reviews_test:
                        for review in self.positive_reviews_test[category]:
                            self.indexed_dataset_test.append([review, category, 1])
                    for category in self.negative_reviews_test:
                        for review in self.negative_reviews_test[category]:
                            self.indexed_dataset_test.append([review, category, 0])
                    random.shuffle(self.indexed_dataset_test)

            def get_vocab_size(self):
                return len(self.vocab)

            def one_hotvec_for_word(self, word):
                word_index =  self.vocab.index(word)
                hotvec = torch.zeros(1, len(self.vocab))
                hotvec[0, word_index] = 1
                return hotvec

            def review_to_tensor(self, review):
                review_tensor = torch.zeros(len(review), len(self.vocab))
                for i,word in enumerate(review):
                    review_tensor[i,:] = self.one_hotvec_for_word(word)
                return review_tensor

            def sentiment_to_tensor(self, sentiment):
                """
                Sentiment is ordinarily just a binary valued thing.  It is 0 for negative
                sentiment and 1 for positive sentiment.  We need to pack this value in a
                two-element tensor.
                """        
                sentiment_tensor = torch.zeros(2)
                if sentiment == 1:
                    sentiment_tensor[1] = 1
                elif sentiment == 0: 
                    sentiment_tensor[0] = 1
                sentiment_tensor = sentiment_tensor.type(torch.long)
                return sentiment_tensor

            def __len__(self):
                if self.train_or_test == 'train':
                    return len(self.indexed_dataset_train)
                elif self.train_or_test == 'test':
                    return len(self.indexed_dataset_test)

            def __getitem__(self, idx):
                sample = self.indexed_dataset_train[idx] if self.train_or_test == 'train' else self.indexed_dataset_test[idx]
                review = sample[0]
                review_category = sample[1]
                review_sentiment = sample[2]
                review_sentiment = self.sentiment_to_tensor(review_sentiment)
                review_tensor = self.review_to_tensor(review)
                category_index = self.categories.index(review_category)
                sample = {'review'       : review_tensor, 
                          'category'     : category_index, # should be converted to tensor, but not yet used
                          'sentiment'    : review_sentiment }
                return sample

        def load_SentimentAnalysisDataset(self, dataserver_train, dataserver_test ):   
            self.train_dataloader = torch.utils.data.DataLoader(dataserver_train,
                        batch_size=self.dl_studio.batch_size,shuffle=True, num_workers=1)
            self.test_dataloader = torch.utils.data.DataLoader(dataserver_test,
                               batch_size=self.dl_studio.batch_size,shuffle=False, num_workers=1)

        class TEXTnet(nn.Module):
            """
            This network is meant for semantic classification of variable-length sentiment 
            data.  Based on my limited testing, the performance of this network is very
            poor because it has no protection against vanishing gradients when used in an
            RNN.

            Class Path:  DLStudio -> TextClassification -> TEXTnet
            """
            def __init__(self, input_size, hidden_size, output_size):
                super(DLStudio.TextClassification.TEXTnet, self).__init__()
                self.input_size = input_size
                self.hidden_size = hidden_size
                self.output_size = output_size
                self.combined_to_hidden = nn.Linear(input_size + hidden_size, hidden_size)
                self.combined_to_middle = nn.Linear(input_size + hidden_size, 100)
                self.middle_to_out = nn.Linear(100, output_size)     
                self.logsoftmax = nn.LogSoftmax(dim=1)
                self.dropout = nn.Dropout(p=0.1)

            def forward(self, input, hidden):
                combined = torch.cat((input, hidden), 1)
                hidden = self.combined_to_hidden(combined)
                hidden = torch.tanh(hidden)                   
                out = self.combined_to_middle(combined)
                out = torch.nn.functional.relu(out)
                out = self.dropout(out)
                out = self.middle_to_out(out)
                out = self.logsoftmax(out)
                return out,hidden         

            def init_hidden(self):
                hidden = torch.zeros(1, self.hidden_size)
                return hidden


        class TEXTnetOrder2(nn.Module):
            """
            In this variant of the TEXTnet network, the value of hidden as used at
            each time step also includes its value at the previous time step.  This 
            fact, not directly apparent by the definition of the class shown below, 
            is made possible by the last parameter, cell, in the header of forward().  
            All you can see here, at the end of forward(), is that the value of cell 
            goes through a linear layer and through a sigmoid nonlinearity. By the way, 
            since the sigmoid saturates at 0 and 1, it can act like a switch. Later 
            when I use this class in the training function, you will see the cell
            values being used in such a manner that the hidden state at each time
            step is mixed with the hidden state at the previous time step.

            Class Path:  DLStudio -> TextClassification -> EXTnetOrder2
            """
            def __init__(self, input_size, hidden_size, output_size):
                super(DLStudio.TextClassification.TEXTnetOrder2, self).__init__()
                self.input_size = input_size
                self.hidden_size = hidden_size
                self.output_size = output_size
                self.combined_to_hidden = nn.Linear(input_size + 2*hidden_size, hidden_size)
                self.combined_to_middle = nn.Linear(input_size + 2*hidden_size, 100)
                self.middle_to_out = nn.Linear(100, output_size)     
                self.logsoftmax = nn.LogSoftmax(dim=1)
                self.dropout = nn.Dropout(p=0.1)
                # for the cell
                self.linear_for_cell = nn.Linear(hidden_size, hidden_size)

            def forward(self, input, hidden, cell):
                combined = torch.cat((input, hidden, cell), 1)
                hidden = self.combined_to_hidden(combined)
                hidden = torch.tanh(hidden)                     
                out = self.combined_to_middle(combined)
                out = torch.nn.functional.relu(out)
                out = self.dropout(out)
                out = self.middle_to_out(out)
                out = self.logsoftmax(out)
                hidden_clone = hidden.clone()
                cell = torch.sigmoid(self.linear_for_cell(hidden_clone))
                return out,hidden,cell         

            def initialize_cell(self):
                weight = next(self.linear_for_cell.parameters()).data
                cell = weight.new(1, self.hidden_size).zero_()
                return cell

            def init_hidden(self):
                hidden = torch.zeros(1, self.hidden_size)
                return hidden


        class GRUnet(nn.Module):
            """
            Source: https://blog.floydhub.com/gru-with-pytorch/
            with the only modification that the final output of forward() is now
            routed through LogSoftmax activation. 

            Class Path: DLStudio  ->  TextClassification  ->  GRUnet
            """
            def __init__(self, input_size, hidden_size, output_size, num_layers, drop_prob=0.2):
                super(DLStudio.TextClassification.GRUnet, self).__init__()
                self.hidden_size = hidden_size
                self.num_layers = num_layers
                self.gru = nn.GRU(input_size, hidden_size, num_layers)
                self.fc = nn.Linear(hidden_size, output_size)
                self.relu = nn.ReLU()
                self.logsoftmax = nn.LogSoftmax(dim=1)
                
            def forward(self, x, h):
                out, h = self.gru(x, h)
                out = self.fc(self.relu(out[:,-1]))
                out = self.logsoftmax(out)
                return out, h

            def init_hidden(self):
                weight = next(self.parameters()).data
                #                                     batch_size   
                hidden = weight.new(  self.num_layers,     1,         self.hidden_size   ).zero_()
                return hidden

        def save_model(self, model):
            "Save the trained model to a disk file"
            torch.save(model.state_dict(), self.dl_studio.path_saved_model)


        def run_code_for_training_with_TEXTnet(self, net, display_train_loss=False):        
            filename_for_out = "performance_numbers_" + str(self.dl_studio.epochs) + ".txt"
            FILE = open(filename_for_out, 'w')
            net.to(self.dl_studio.device)
            ## Note that the TEXTnet and TEXTnetOrder2 both produce LogSoftmax output:
            criterion = nn.NLLLoss()
            accum_times = []
            optimizer = optim.SGD(net.parameters(), 
                         lr=self.dl_studio.learning_rate, momentum=self.dl_studio.momentum)
            start_time = time.perf_counter()
            training_loss_tally = []
            for epoch in range(self.dl_studio.epochs):  
                print("")
                running_loss = 0.0
                for i, data in enumerate(self.train_dataloader):    
                    hidden = net.init_hidden().to(self.dl_studio.device)              
                    review_tensor,category,sentiment = data['review'], data['category'], data['sentiment']
                    review_tensor = review_tensor.to(self.dl_studio.device)
                    sentiment = sentiment.to(self.dl_studio.device)
                    optimizer.zero_grad()
                    input = torch.zeros(1,review_tensor.shape[2])
                    input = input.to(self.dl_studio.device)
                    for k in range(review_tensor.shape[1]):
                        input[0,:] = review_tensor[0,k]
                        output, hidden = net(input, hidden)
                    loss = criterion(output, torch.argmax(sentiment,1))
                    running_loss += loss.item()
                    loss.backward(retain_graph=True)        
                    optimizer.step()
                    if i % 200 == 199:    
                        avg_loss = running_loss / float(200)
                        training_loss_tally.append(avg_loss)
                        current_time = time.perf_counter()
                        time_elapsed = current_time-start_time
                        print("[epoch:%d  iter:%4d  elapsed_time: %4d secs]     loss: %.5f" % (epoch+1,i+1, time_elapsed,avg_loss))
                        accum_times.append(current_time-start_time)
                        FILE.write("%.3f\n" % avg_loss)
                        FILE.flush()
                        running_loss = 0.0
            print("\nFinished Training\n")
            self.save_model(net)
            if display_train_loss:
                plt.figure(figsize=(10,5))
                plt.title("Training Loss vs. Iterations")
                plt.plot(training_loss_tally)
                plt.xlabel("iterations")
                plt.ylabel("training loss")
                plt.legend()
                plt.savefig("training_loss.png")
                plt.show()


        def run_code_for_training_with_TEXTnetOrder2(self, net, display_train_loss=False):        
            filename_for_out = "performance_numbers_" + str(self.dl_studio.epochs) + ".txt"
            FILE = open(filename_for_out, 'w')
            net.to(self.dl_studio.device)
            ## Note that the TEXTnet and TEXTnetOrder2 both produce LogSoftmax output:
            criterion = nn.NLLLoss()
            accum_times = []
            optimizer = optim.SGD(net.parameters(), 
                         lr=self.dl_studio.learning_rate, momentum=self.dl_studio.momentum)
            start_time = time.perf_counter()
            training_loss_tally = []
            for epoch in range(self.dl_studio.epochs):  
                print("")
                running_loss = 0.0
                for i, data in enumerate(self.train_dataloader):    
                    hidden = net.init_hidden().to(self.dl_studio.device)              
                    cell_prev = net.initialize_cell().to(self.dl_studio.device)
                    cell_prev_2_prev = net.initialize_cell().to(self.dl_studio.device)
                    review_tensor,category,sentiment = data['review'], data['category'], data['sentiment']
                    review_tensor = review_tensor.to(self.dl_studio.device)
                    sentiment = sentiment.to(self.dl_studio.device)
                    optimizer.zero_grad()
                    input = torch.zeros(1,review_tensor.shape[2])
                    input = input.to(self.dl_studio.device)
                    for k in range(review_tensor.shape[1]):
                        input[0,:] = review_tensor[0,k]
                        output, hidden, cell = net(input, hidden, cell_prev_2_prev)
                        if k == 0:
                            cell_prev = cell
                        else:
                            cell_prev_2_prev = cell_prev
                            cell_prev = cell
                    loss = criterion(output, torch.argmax(sentiment,1))
                    running_loss += loss.item()
                    loss.backward()        
                    optimizer.step()
                    if i % 200 == 199:    
                        avg_loss = running_loss / float(200)
                        training_loss_tally.append(avg_loss)
                        current_time = time.perf_counter()
                        time_elapsed = current_time-start_time
                        print("[epoch:%d  iter:%4d  elapsed_time: %4d secs]     loss: %.5f" % (epoch+1,i+1, time_elapsed,avg_loss))
                        accum_times.append(current_time-start_time)
                        FILE.write("%.3f\n" % avg_loss)
                        FILE.flush()
                        running_loss = 0.0
            print("\nFinished Training\n")
            self.save_model(net)
            if display_train_loss:
                plt.figure(figsize=(10,5))
                plt.title("Training Loss vs. Iterations")
                plt.plot(training_loss_tally)
                plt.xlabel("iterations")
                plt.ylabel("training loss")
                plt.legend()
                plt.savefig("training_loss.png")
                plt.show()


        def run_code_for_training_for_text_classification_with_GRU(self, net, display_train_loss=False): 
            filename_for_out = "performance_numbers_" + str(self.dl_studio.epochs) + ".txt"
            FILE = open(filename_for_out, 'w')
            net.to(self.dl_studio.device)
            ##  Note that the GREnet now produces the LogSoftmax output:
            criterion = nn.NLLLoss()
            accum_times = []
            optimizer = optim.SGD(net.parameters(), 
                         lr=self.dl_studio.learning_rate, momentum=self.dl_studio.momentum)
            start_time = time.perf_counter()
            training_loss_tally = []
            for epoch in range(self.dl_studio.epochs):  
                print("")
                running_loss = 0.0
                for i, data in enumerate(self.train_dataloader):    
                    review_tensor,category,sentiment = data['review'], data['category'], data['sentiment']
                    review_tensor = review_tensor.to(self.dl_studio.device)
                    sentiment = sentiment.to(self.dl_studio.device)
                    ## The following type conversion needed for MSELoss:
                    ##sentiment = sentiment.float()
                    optimizer.zero_grad()
                    hidden = net.init_hidden().to(self.dl_studio.device)
                    for k in range(review_tensor.shape[1]):
                        output, hidden = net(torch.unsqueeze(torch.unsqueeze(review_tensor[0,k],0),0), hidden)
                    ## If using NLLLoss, CrossEntropyLoss
                    loss = criterion(output, torch.argmax(sentiment, 1))
                    ## If using MSELoss:
                    ## loss = criterion(output, sentiment)     
                    running_loss += loss.item()
                    loss.backward()
                    optimizer.step()
                    if i % 200 == 199:    
                        avg_loss = running_loss / float(200)
                        training_loss_tally.append(avg_loss)
                        current_time = time.perf_counter()
                        time_elapsed = current_time-start_time
                        print("[epoch:%d  iter:%4d  elapsed_time:%4d secs]     loss: %.5f" % (epoch+1,i+1, time_elapsed,avg_loss))
                        accum_times.append(current_time-start_time)
                        FILE.write("%.3f\n" % avg_loss)
                        FILE.flush()
                        running_loss = 0.0
            print("Total Training Time: {}".format(str(sum(accum_times))))
            print("\nFinished Training\n")
            self.save_model(net)
            if display_train_loss:
                plt.figure(figsize=(10,5))
                plt.title("Training Loss vs. Iterations")
                plt.plot(training_loss_tally)
                plt.xlabel("iterations")
                plt.ylabel("training loss")
                plt.legend()
                plt.savefig("training_loss.png")
                plt.show()


        def run_code_for_testing_with_TEXTnet(self, net):
            net.load_state_dict(torch.load(self.dl_studio.path_saved_model))
            net.to(self.dl_studio.device)
            classification_accuracy = 0.0
            negative_total = 0
            positive_total = 0
            confusion_matrix = torch.zeros(2,2)
            with torch.no_grad():
                for i, data in enumerate(self.test_dataloader):
                    review_tensor,category,sentiment = data['review'], data['category'], data['sentiment']
                    input = torch.zeros(1,review_tensor.shape[2]).to(self.dl_studio.device)
                    hidden = net.init_hidden().to(self.dl_studio.device)
                    for k in range(review_tensor.shape[1]):
                        input[0,:] = review_tensor[0,k]
                        output, hidden = net(input, hidden)
                    predicted_idx = torch.argmax(output).item()
                    gt_idx = torch.argmax(sentiment).item()
                    if i % 100 == 99:
                        print("   [i=%4d]    predicted_label=%d       gt_label=%d" % (i+1, predicted_idx,gt_idx))
                    if predicted_idx == gt_idx:
                        classification_accuracy += 1
                    if gt_idx == 0: 
                        negative_total += 1
                    elif gt_idx == 1:
                        positive_total += 1
                    confusion_matrix[gt_idx,predicted_idx] += 1
            print("\nOverall classification accuracy: %0.2f%%" %  (float(classification_accuracy) * 100 /float(i)))
            out_percent = np.zeros((2,2), dtype='float')
            out_percent[0,0] = "%.3f" % (100 * confusion_matrix[0,0] / float(negative_total))
            out_percent[0,1] = "%.3f" % (100 * confusion_matrix[0,1] / float(negative_total))
            out_percent[1,0] = "%.3f" % (100 * confusion_matrix[1,0] / float(positive_total))
            out_percent[1,1] = "%.3f" % (100 * confusion_matrix[1,1] / float(positive_total))
            print("\n\nNumber of positive reviews tested: %d" % positive_total)
            print("\n\nNumber of negative reviews tested: %d" % negative_total)
            print("\n\nDisplaying the confusion matrix:\n")
            out_str = "                      "
            out_str +=  "%18s    %18s" % ('predicted negative', 'predicted positive')
            print(out_str + "\n")
            for i,label in enumerate(['true negative', 'true positive']):
                out_str = "%12s:  " % label
                for j in range(2):
                    out_str +=  "%18s" % out_percent[i,j]
                print(out_str)

        def run_code_for_testing_with_TEXTnetOrder2(self, net):
            net.load_state_dict(torch.load(self.dl_studio.path_saved_model))
            net.to(self.dl_studio.device)
            classification_accuracy = 0.0
            negative_total = 0
            positive_total = 0
            confusion_matrix = torch.zeros(2,2)
            with torch.no_grad():
                for i, data in enumerate(self.test_dataloader):
                    cell_prev = net.initialize_cell()
                    cell_prev_2_prev = net.initialize_cell()
                    review_tensor,category,sentiment = data['review'], data['category'], data['sentiment']
                    input = torch.zeros(1,review_tensor.shape[2]).to(self.dl_studio.device)
                    hidden = net.init_hidden().to(self.dl_studio.device)
                    for k in range(review_tensor.shape[1]):
                        input[0,:] = review_tensor[0,k]
                        output, hidden, cell = net(input, hidden, cell_prev_2_prev)
                        if k == 0:
                            cell_prev = cell
                        else:
                            cell_prev_2_prev = cell_prev
                            cell_prev = cell
                    predicted_idx = torch.argmax(output).item()
                    gt_idx = torch.argmax(sentiment).item()
                    if i % 100 == 99:
                        print("   [i=%4d]    predicted_label=%d       gt_label=%d" % (i+1, predicted_idx,gt_idx))
                    if predicted_idx == gt_idx:
                        classification_accuracy += 1
                    if gt_idx == 0: 
                        negative_total += 1
                    elif gt_idx == 1:
                        positive_total += 1
                    confusion_matrix[gt_idx,predicted_idx] += 1
            print("\nOverall classification accuracy: %0.2f%%" %  (float(classification_accuracy) * 100 /float(i)))
            out_percent = np.zeros((2,2), dtype='float')
            out_percent[0,0] = "%.3f" % (100 * confusion_matrix[0,0] / float(negative_total))
            out_percent[0,1] = "%.3f" % (100 * confusion_matrix[0,1] / float(negative_total))
            out_percent[1,0] = "%.3f" % (100 * confusion_matrix[1,0] / float(positive_total))
            out_percent[1,1] = "%.3f" % (100 * confusion_matrix[1,1] / float(positive_total))
            print("\n\nNumber of positive reviews tested: %d" % positive_total)
            print("\n\nNumber of negative reviews tested: %d" % negative_total)
            print("\n\nDisplaying the confusion matrix:\n")
            out_str = "                      "
            out_str +=  "%18s    %18s" % ('predicted negative', 'predicted positive')
            print(out_str + "\n")
            for i,label in enumerate(['true negative', 'true positive']):
                out_str = "%12s:  " % label
                for j in range(2):
                    out_str +=  "%18s" % out_percent[i,j]
                print(out_str)


        def run_code_for_testing_text_classification_with_GRU(self, net):
            net.load_state_dict(torch.load(self.dl_studio.path_saved_model))
            net.to(self.dl_studio.device)
            classification_accuracy = 0.0
            negative_total = 0
            positive_total = 0
            confusion_matrix = torch.zeros(2,2)
            with torch.no_grad():
                for i, data in enumerate(self.test_dataloader):
                    review_tensor,category,sentiment = data['review'], data['category'], data['sentiment']
                    hidden = net.init_hidden().to(self.dl_studio.device)
                    for k in range(review_tensor.shape[1]):
                        output, hidden = net(torch.unsqueeze(torch.unsqueeze(review_tensor[0,k],0),0), hidden)
                    predicted_idx = torch.argmax(output).item()
                    gt_idx = torch.argmax(sentiment).item()
                    if i % 100 == 99:
                        print("   [i=%d]    predicted_label=%d       gt_label=%d\n\n" % (i+1, predicted_idx,gt_idx))
                    if predicted_idx == gt_idx:
                        classification_accuracy += 1
                    if gt_idx == 0: 
                        negative_total += 1
                    elif gt_idx == 1:
                        positive_total += 1
                    confusion_matrix[gt_idx,predicted_idx] += 1
            print("\nOverall classification accuracy: %0.2f%%" %  (float(classification_accuracy) * 100 /float(i)))
            out_percent = np.zeros((2,2), dtype='float')
            out_percent[0,0] = "%.3f" % (100 * confusion_matrix[0,0] / float(negative_total))
            out_percent[0,1] = "%.3f" % (100 * confusion_matrix[0,1] / float(negative_total))
            out_percent[1,0] = "%.3f" % (100 * confusion_matrix[1,0] / float(positive_total))
            out_percent[1,1] = "%.3f" % (100 * confusion_matrix[1,1] / float(positive_total))
            print("\n\nNumber of positive reviews tested: %d" % positive_total)
            print("\n\nNumber of negative reviews tested: %d" % negative_total)
            print("\n\nDisplaying the confusion matrix:\n")
            out_str = "                      "
            out_str +=  "%18s    %18s" % ('predicted negative', 'predicted positive')
            print(out_str + "\n")
            for i,label in enumerate(['true negative', 'true positive']):
                out_str = "%12s:  " % label
                for j in range(2):
                    out_str +=  "%18s" % out_percent[i,j]
                print(out_str)


    ###%%%
    ########################################################################################
    ########  Start Definition of Inner Class TextClassificationWithEmbeddings  ############

    class TextClassificationWithEmbeddings(nn.Module):             
        """
        The text processing class described previously, TextClassification, was based on
        using one-hot vectors for representing the words.  The main challenge we faced
        with one-hot vectors was that the larger the size of the training dataset, the
        larger the size of the vocabulary, and, therefore, the larger the size of the
        one-hot vectors.  The increase in the size of the one-hot vectors led to a
        model with a significantly larger number of learnable parameters --- and, that,
        in turn, created a need for a still larger training dataset.  Sounds like a classic
        example of a vicious circle.  In this section, I use the idea of word embeddings
        to break out of this vicious circle.

        Word embeddings are fixed-sized numerical representations for words that are
        learned on the basis of the similarity of word contexts.  The original and still
        the most famous of these representations are known as the word2vec
        embeddings. The embeddings that I use in this section consist of pre-trained
        300-element word vectors for 3 million words and phrases as learned from Google
        News reports.  I access these embeddings through the popular Gensim library.
 
        Class Path:  DLStudio -> TextClassificationWithEmbeddings
        """
        def __init__(self, dl_studio,dataserver_train=None,dataserver_test=None,dataset_file_train=None,dataset_file_test=None):
            super(DLStudio.TextClassificationWithEmbeddings, self).__init__()
            self.dl_studio = dl_studio
            self.dataserver_train = dataserver_train
            self.dataserver_test = dataserver_test

        class SentimentAnalysisDataset(torch.utils.data.Dataset):
            """
            In relation to the SentimentAnalysisDataset defined for the TextClassification section of 
            DLStudio, the __getitem__() method of the dataloader must now fetch the embeddings from
            the word2vec word vectors.

            Class Path:  DLStudio -> TextClassificationWithEmbeddings -> SentimentAnalysisDataset
            """
            def __init__(self, dl_studio, train_or_test, dataset_file, path_to_saved_embeddings=None):
                super(DLStudio.TextClassificationWithEmbeddings.SentimentAnalysisDataset, self).__init__()
                import gensim.downloader as gen_api
#                self.word_vectors = gen_api.load("word2vec-google-news-300")
                self.path_to_saved_embeddings = path_to_saved_embeddings
                self.train_or_test = train_or_test
                root_dir = dl_studio.dataroot
                f = gzip.open(root_dir + dataset_file, 'rb')
                dataset = f.read()
                if path_to_saved_embeddings is not None:
                    import gensim.downloader as genapi
                    from gensim.models import KeyedVectors 
                    if os.path.exists(path_to_saved_embeddings + 'vectors.kv'):
                        self.word_vectors = KeyedVectors.load(path_to_saved_embeddings + 'vectors.kv')
                    else:
                        print("""\n\nSince this is your first time to install the word2vec embeddings, it may take"""
                              """\na couple of minutes. The embeddings occupy around 3.6GB of your disk space.\n\n""")
                        self.word_vectors = genapi.load("word2vec-google-news-300")               
                        ##  'kv' stands for  "KeyedVectors", a special datatype used by gensim because it 
                        ##  has a smaller footprint than dict
                        self.word_vectors.save(path_to_saved_embeddings + 'vectors.kv')    
                if train_or_test == 'train':
                    if sys.version_info[0] == 3:
                        self.positive_reviews_train, self.negative_reviews_train, self.vocab = pickle.loads(dataset, encoding='latin1')
                    else:
                        self.positive_reviews_train, self.negative_reviews_train, self.vocab = pickle.loads(dataset)
                    self.categories = sorted(list(self.positive_reviews_train.keys()))
                    self.category_sizes_train_pos = {category : len(self.positive_reviews_train[category]) for category in self.categories}
                    self.category_sizes_train_neg = {category : len(self.negative_reviews_train[category]) for category in self.categories}
                    self.indexed_dataset_train = []
                    for category in self.positive_reviews_train:
                        for review in self.positive_reviews_train[category]:
                            self.indexed_dataset_train.append([review, category, 1])
                    for category in self.negative_reviews_train:
                        for review in self.negative_reviews_train[category]:
                            self.indexed_dataset_train.append([review, category, 0])
                    random.shuffle(self.indexed_dataset_train)
                elif train_or_test == 'test':
                    if sys.version_info[0] == 3:
                        self.positive_reviews_test, self.negative_reviews_test, self.vocab = pickle.loads(dataset, encoding='latin1')
                    else:
                        self.positive_reviews_test, self.negative_reviews_test, self.vocab = pickle.loads(dataset)
                    self.vocab = sorted(self.vocab)
                    self.categories = sorted(list(self.positive_reviews_test.keys()))
                    self.category_sizes_test_pos = {category : len(self.positive_reviews_test[category]) for category in self.categories}
                    self.category_sizes_test_neg = {category : len(self.negative_reviews_test[category]) for category in self.categories}
                    self.indexed_dataset_test = []
                    for category in self.positive_reviews_test:
                        for review in self.positive_reviews_test[category]:
                            self.indexed_dataset_test.append([review, category, 1])
                    for category in self.negative_reviews_test:
                        for review in self.negative_reviews_test[category]:
                            self.indexed_dataset_test.append([review, category, 0])
                    random.shuffle(self.indexed_dataset_test)

            def review_to_tensor(self, review):
                list_of_embeddings = []
                for i,word in enumerate(review):
                    if word in self.word_vectors.key_to_index:
                        embedding = self.word_vectors[word]
                        list_of_embeddings.append(np.array(embedding))
                    else:
                        next
                review_tensor = torch.FloatTensor( list_of_embeddings )
                return review_tensor

            def sentiment_to_tensor(self, sentiment):
                """
                Sentiment is ordinarily just a binary valued thing.  It is 0 for negative
                sentiment and 1 for positive sentiment.  We need to pack this value in a
                two-element tensor.
                """        
                sentiment_tensor = torch.zeros(2)
                if sentiment == 1:
                    sentiment_tensor[1] = 1
                elif sentiment == 0: 
                    sentiment_tensor[0] = 1
                sentiment_tensor = sentiment_tensor.type(torch.long)
                return sentiment_tensor

            def __len__(self):
                if self.train_or_test == 'train':
                    return len(self.indexed_dataset_train)
                elif self.train_or_test == 'test':
                    return len(self.indexed_dataset_test)

            def __getitem__(self, idx):
                sample = self.indexed_dataset_train[idx] if self.train_or_test == 'train' else self.indexed_dataset_test[idx]
                review = sample[0]
                review_category = sample[1]
                review_sentiment = sample[2]
                review_sentiment = self.sentiment_to_tensor(review_sentiment)
                review_tensor = self.review_to_tensor(review)
                category_index = self.categories.index(review_category)
                sample = {'review'       : review_tensor, 
                          'category'     : category_index, # should be converted to tensor, but not yet used
                          'sentiment'    : review_sentiment }
                return sample

        def load_SentimentAnalysisDataset(self, dataserver_train, dataserver_test ):   
            self.train_dataloader = torch.utils.data.DataLoader(dataserver_train,
                        batch_size=self.dl_studio.batch_size,shuffle=True, num_workers=2)
            self.test_dataloader = torch.utils.data.DataLoader(dataserver_test,
                               batch_size=self.dl_studio.batch_size,shuffle=False, num_workers=2)

        class TEXTnetWithEmbeddings(nn.Module):
            """
            This is embeddings version of the class TEXTnet class shown previously.  Since we
            are using the word2vec embeddings, we know that the input size for each word vector 
            will be a constant value of 300.  Overall, though, this network is meant for semantic 
            classification of variable-length sentiment data.  Based on my limited testing, the 
            performance of this network is very poor because it has no protection against 
            vanishing gradients when used in an RNN.  

            Class Path:  DLStudio -> TextClassificationWithEmbeddings -> TEXTnetWithEmbeddings
            """
            def __init__(self, input_size, hidden_size, output_size):
                super(DLStudio.TextClassificationWithEmbeddings.TEXTnetWithEmbeddings, self).__init__()
                self.input_size = input_size
                self.hidden_size = hidden_size
                self.output_size = output_size
                self.combined_to_hidden = nn.Linear(input_size + hidden_size, hidden_size)
                self.combined_to_middle = nn.Linear(input_size + hidden_size, 100)
                self.middle_to_out = nn.Linear(100, output_size)     
                self.logsoftmax = nn.LogSoftmax(dim=1)

            def forward(self, input, hidden):
                combined = torch.cat((input, hidden), 1)
                hidden = self.combined_to_hidden(combined)
                hidden = torch.tanh(hidden)                     
                out = self.combined_to_middle(combined)
                out = torch.nn.functional.relu(out)
                out = self.middle_to_out(out)
                out = self.logsoftmax(out)
                return out,hidden         

            def init_hidden(self):
                hidden = torch.zeros(1, self.hidden_size)
                return hidden


        class TEXTnetOrder2WithEmbeddings(nn.Module):
            """
            This is an embeddings version of the TEXTnetOrder2 class shown previously.
            With the embeddings, we know that the size the tensor for word will be 300.
            As to how TEXTnetOrder2 differs from TEXTnet, the value of hidden as used at
            each time step also includes its value at the previous time step.  This 
            fact, not directly apparent by the definition of the class shown below, 
            is made possible by the last parameter, cell, in the header of forward().  
            All you can see here, at the end of forward(), is that the value of cell 
            goes through a linear layer and through a sigmoid nonlinearity. By the way, 
            since the sigmoid saturates at 0 and 1, it can act like a switch. Later 
            when I use this class in the training function, you will see the cell
            values being used in such a manner that the hidden state at each time
            step is mixed with the hidden state at the previous time step.

            Class Path:  DLStudio -> TextClassificationWithEmbeddings -> TEXTnetOrder2WithEmbeddings
            """
            def __init__(self, hidden_size, output_size, input_size=300):
                super(DLStudio.TextClassificationWithEmbeddings.TEXTnetOrder2WithEmbeddings, self).__init__()
                self.input_size = input_size
                self.hidden_size = hidden_size
                self.output_size = output_size
                self.combined_to_hidden = nn.Linear(input_size + 2*hidden_size, hidden_size)
                self.combined_to_middle = nn.Linear(input_size + 2*hidden_size, 100)
                self.middle_to_out = nn.Linear(100, output_size)     
                self.logsoftmax = nn.LogSoftmax(dim=1)
                self.dropout = nn.Dropout(p=0.1)
                # for the cell
                self.linear_for_cell = nn.Linear(hidden_size, hidden_size)

            def forward(self, input, hidden, cell):
                combined = torch.cat((input, hidden, cell), 1)
                hidden = self.combined_to_hidden(combined)
                hidden = torch.tanh(hidden)                     
                out = self.combined_to_middle(combined)
                out = torch.nn.functional.relu(out)
                out = self.dropout(out)
                out = self.middle_to_out(out)
                out = self.logsoftmax(out)
                hidden_clone = hidden.clone()
#                cell = torch.tanh(self.linear_for_cell(hidden_clone))
                cell = torch.sigmoid(self.linear_for_cell(hidden_clone))
                return out,hidden,cell         

            def initialize_cell(self):
                weight = next(self.linear_for_cell.parameters()).data
                cell = weight.new(1, self.hidden_size).zero_()
                return cell

            def init_hidden(self):
                hidden = torch.zeros(1, self.hidden_size)
                return hidden


        class GRUnetWithEmbeddings(nn.Module):
            """
            For this embeddings adapted version of the GRUnet shown earlier, we can assume that
            the 'input_size' for a tensor representing a word is always 300.
            Source: https://blog.floydhub.com/gru-with-pytorch/
            with the only modification that the final output of forward() is now
            routed through LogSoftmax activation. 

            Class Path:  DLStudio -> TextClassificationWithEmbeddings -> GRUnetWithEmbeddings 
            """
            def __init__(self, input_size, hidden_size, output_size, num_layers=1): 
                """
                -- input_size is the size of the tensor for each word in a sequence of words.  If you word2vec
                       embedding, the value of this variable will always be equal to 300.
                -- hidden_size is the size of the hidden state in the RNN
                -- output_size is the size of output of the RNN.  For binary classification of 
                       input text, output_size is 2.
                -- num_layers creates a stack of GRUs
                """
                super(DLStudio.TextClassificationWithEmbeddings.GRUnetWithEmbeddings, self).__init__()
                self.input_size = input_size
                self.hidden_size = hidden_size
                self.num_layers = num_layers
                self.gru = nn.GRU(input_size, hidden_size, num_layers)
                self.fc = nn.Linear(hidden_size, output_size)
                self.relu = nn.ReLU()
                self.logsoftmax = nn.LogSoftmax(dim=1)
                
            def forward(self, x, h):
                out, h = self.gru(x, h)
                out = self.fc(self.relu(out[:,-1]))
                out = self.logsoftmax(out)
                return out, h

            def init_hidden(self):
                weight = next(self.parameters()).data
                #                  num_layers  batch_size    hidden_size
                hidden = weight.new(  2,          1,         self.hidden_size    ).zero_()
                return hidden

        def save_model(self, model):
            "Save the trained model to a disk file"
            torch.save(model.state_dict(), self.dl_studio.path_saved_model)


        def run_code_for_training_with_TEXTnet_word2vec(self, net, display_train_loss=False):        
            filename_for_out = "performance_numbers_" + str(self.dl_studio.epochs) + ".txt"
            FILE = open(filename_for_out, 'w')
            net = copy.deepcopy(net)
            net = net.to(self.dl_studio.device)
            ## Note that the TEXTnet and TEXTnetOrder2 both produce LogSoftmax output. So we
            ## use nn.NLLLoss. The combined effect of LogSoftMax and NLLLoss is the same as 
            ## for the CrossEntropyLoss
            criterion = nn.NLLLoss()
            accum_times = []
            optimizer = optim.SGD(net.parameters(), 
                         lr=self.dl_studio.learning_rate, momentum=self.dl_studio.momentum)
            start_time = time.perf_counter()
            training_loss_tally = []
            for epoch in range(self.dl_studio.epochs):  
                print("")
                running_loss = 0.0
                for i, data in enumerate(self.train_dataloader):    
                    hidden = net.init_hidden().to(self.dl_studio.device)              
                    review_tensor,category,sentiment = data['review'], data['category'], data['sentiment']
                    review_tensor = review_tensor.to(self.dl_studio.device)
                    sentiment = sentiment.to(self.dl_studio.device)
                    optimizer.zero_grad()
                    input = torch.zeros(1,review_tensor.shape[2]).to(self.dl_studio.device)
                    for k in range(review_tensor.shape[1]):
                        input[0,:] = review_tensor[0,k]
                        output, hidden = net(input, hidden)
                    loss = criterion(output, torch.argmax(sentiment,1))
                    running_loss += loss.item()
                    loss.backward(retain_graph=True)        
                    optimizer.step()
                    if i % 200 == 199:    
                        avg_loss = running_loss / float(200)
                        training_loss_tally.append(avg_loss)
                        running_loss = 0.0
                        current_time = time.perf_counter()
                        time_elapsed = current_time-start_time
                        print("[epoch:%d  iter:%4d  elapsed_time: %4d secs]     loss: %.5f" % (epoch+1,i+1, time_elapsed,avg_loss))
                        accum_times.append(current_time-start_time)
                        FILE.write("%.3f\n" % avg_loss)
                        FILE.flush()
            print("\nFinished Training\n\n")
            self.save_model(net)
            if display_train_loss:
                plt.figure(figsize=(10,5))
                plt.title("Training Loss vs. Iterations")
                plt.plot(training_loss_tally)
                plt.xlabel("iterations")
                plt.ylabel("training loss")
                plt.legend()
                plt.savefig("training_loss.png")
                plt.show()


        def run_code_for_training_with_TEXTnetOrder2_word2vec(self, net, display_train_loss=False):        
            filename_for_out = "performance_numbers_" + str(self.dl_studio.epochs) + ".txt"
            FILE = open(filename_for_out, 'w')
            net = copy.deepcopy(net)
            net.to(self.dl_studio.device)
            ## Note that the TEXTnet and TEXTnetOrder2 both produce LogSoftmax output:
            criterion = nn.NLLLoss()
            accum_times = []
            optimizer = optim.SGD(net.parameters(), 
                                       lr=self.dl_studio.learning_rate, momentum=self.dl_studio.momentum)
            start_time = time.perf_counter()
            training_loss_tally = []
            for epoch in range(self.dl_studio.epochs):  
                print("")
                running_loss = 0.0
                for i, data in enumerate(self.train_dataloader):    
                    cell_prev = net.initialize_cell().to(self.dl_studio.device)
                    cell_prev_2_prev = net.initialize_cell().to(self.dl_studio.device)
                    hidden = net.init_hidden().to(self.dl_studio.device)              
                    review_tensor,category,sentiment = data['review'], data['category'], data['sentiment']
                    review_tensor = review_tensor.to(self.dl_studio.device)
                    sentiment = sentiment.to(self.dl_studio.device)
                    optimizer.zero_grad()
                    input = torch.zeros(1,review_tensor.shape[2])
                    input = input.to(self.dl_studio.device)
                    for k in range(review_tensor.shape[1]):
                        input[0,:] = review_tensor[0,k]
                        output, hidden, cell = net(input, hidden, cell_prev_2_prev)
                        if k == 0:
                            cell_prev = cell
                        else:
                            cell_prev_2_prev = cell_prev
                            cell_prev = cell
                    loss = criterion(output, torch.argmax(sentiment,1))
                    running_loss += loss.item()
                    loss.backward()        
                    optimizer.step()
                    if i % 200 == 199:    
                        avg_loss = running_loss / float(200)
                        training_loss_tally.append(avg_loss)
                        current_time = time.perf_counter()
                        time_elapsed = current_time-start_time
                        print("[epoch:%d  iter:%4d  elapsed_time: %4d secs]     loss: %.5f" % (epoch+1,i+1, time_elapsed,avg_loss))
                        accum_times.append(current_time-start_time)
                        FILE.write("%.3f\n" % avg_loss)
                        FILE.flush()
                        running_loss = 0.0
            print("\nFinished Training\n")
            self.save_model(net)
            if display_train_loss:
                plt.figure(figsize=(10,5))
                plt.title("Training Loss vs. Iterations")
                plt.plot(training_loss_tally)
                plt.xlabel("iterations")
                plt.ylabel("training loss")
                plt.legend()
                plt.savefig("training_loss.png")
                plt.show()


        def run_code_for_training_for_text_classification_with_GRU_word2vec(self, net, display_train_loss=False): 
            filename_for_out = "performance_numbers_" + str(self.dl_studio.epochs) + ".txt"
            FILE = open(filename_for_out, 'w')
            net = copy.deepcopy(net)
            net = net.to(self.dl_studio.device)
            ##  Note that the GREnet now produces the LogSoftmax output:
            criterion = nn.NLLLoss()
            accum_times = []
            optimizer = optim.SGD(net.parameters(), 
                         lr=self.dl_studio.learning_rate, momentum=self.dl_studio.momentum)
            training_loss_tally = []
            start_time = time.perf_counter()
            for epoch in range(self.dl_studio.epochs):  
                print("")
                running_loss = 0.0
                for i, data in enumerate(self.train_dataloader):    
                    review_tensor,category,sentiment = data['review'], data['category'], data['sentiment']
                    review_tensor = review_tensor.to(self.dl_studio.device)
                    sentiment = sentiment.to(self.dl_studio.device)
                    ## The following type conversion needed for MSELoss:
                    ##sentiment = sentiment.float()
                    optimizer.zero_grad()
                    hidden = net.init_hidden().to(self.dl_studio.device)
                    for k in range(review_tensor.shape[1]):
                        output, hidden = net(torch.unsqueeze(torch.unsqueeze(review_tensor[0,k],0),0), hidden)
                    loss = criterion(output, torch.argmax(sentiment, 1))
                    running_loss += loss.item()
                    loss.backward()
                    optimizer.step()
                    if i % 200 == 199:    
                        avg_loss = running_loss / float(200)
                        training_loss_tally.append(avg_loss)
                        current_time = time.perf_counter()
                        time_elapsed = current_time-start_time
                        print("[epoch:%d  iter:%4d  elapsed_time:%4d secs]     loss: %.5f" % (epoch+1,i+1, time_elapsed,avg_loss))
                        accum_times.append(current_time-start_time)
                        FILE.write("%.5f\n" % avg_loss)
                        FILE.flush()
                        running_loss = 0.0
            self.save_model(net)
            print("Total Training Time: {}".format(str(sum(accum_times))))
            print("\nFinished Training\n\n")
            if display_train_loss:
                plt.figure(figsize=(10,5))
                plt.title("Training Loss vs. Iterations")
                plt.plot(training_loss_tally)
                plt.xlabel("iterations")
                plt.ylabel("training loss")
                plt.legend()
                plt.savefig("training_loss.png")
                plt.show()


        def run_code_for_testing_with_TEXTnet_word2vec(self, net):
            net.load_state_dict(torch.load(self.dl_studio.path_saved_model))
            net.to(self.dl_studio.device)
            classification_accuracy = 0.0
            negative_total = 0
            positive_total = 0
            confusion_matrix = torch.zeros(2,2)
            with torch.no_grad():
                for i, data in enumerate(self.test_dataloader):
                    review_tensor,category,sentiment = data['review'], data['category'], data['sentiment']
                    review_tensor = review_tensor.to(self.dl_studio.device)
                    category      = category.to(self.dl_studio.device)
                    sentiment     = sentiment.to(self.dl_studio.device)
                    input = torch.zeros(1,review_tensor.shape[2]).to(self.dl_studio.device)
                    hidden = net.init_hidden().to(self.dl_studio.device)
                    for k in range(review_tensor.shape[1]):
                        input[0,:] = review_tensor[0,k]
                        output, hidden = net(input, hidden)
                    predicted_idx = torch.argmax(output).item()
                    gt_idx = torch.argmax(sentiment).item()
                    if i % 100 == 99:
                        print("   [i=%4d]    predicted_label=%d       gt_label=%d" % (i+1, predicted_idx,gt_idx))
                    if predicted_idx == gt_idx:
                        classification_accuracy += 1
                    if gt_idx == 0: 
                        negative_total += 1
                    elif gt_idx == 1:
                        positive_total += 1
                    confusion_matrix[gt_idx,predicted_idx] += 1
            print("\nOverall classification accuracy: %0.2f%%" %  (float(classification_accuracy) * 100 /float(i)))
            out_percent = np.zeros((2,2), dtype='float')
            out_percent[0,0] = "%.3f" % (100 * confusion_matrix[0,0] / float(negative_total))
            out_percent[0,1] = "%.3f" % (100 * confusion_matrix[0,1] / float(negative_total))
            out_percent[1,0] = "%.3f" % (100 * confusion_matrix[1,0] / float(positive_total))
            out_percent[1,1] = "%.3f" % (100 * confusion_matrix[1,1] / float(positive_total))
            print("\n\nNumber of positive reviews tested: %d" % positive_total)
            print("\n\nNumber of negative reviews tested: %d" % negative_total)
            print("\n\nDisplaying the confusion matrix:\n")
            out_str = "                      "
            out_str +=  "%18s    %18s" % ('predicted negative', 'predicted positive')
            print(out_str + "\n")
            for i,label in enumerate(['true negative', 'true positive']):
                out_str = "%12s%%:  " % label
                for j in range(2):
                    out_str +=  "%18s%%" % out_percent[i,j]
                print(out_str)


        def run_code_for_testing_with_TEXTnetOrder2_word2vec(self, net):
            net.load_state_dict(torch.load(self.dl_studio.path_saved_model))
            net.to(self.dl_studio.device)
            classification_accuracy = 0.0
            negative_total = 0
            positive_total = 0
            confusion_matrix = torch.zeros(2,2)
            with torch.no_grad():
                for i, data in enumerate(self.test_dataloader):
                    cell_prev = net.initialize_cell()
                    cell_prev_2_prev = net.initialize_cell()
                    review_tensor,category,sentiment = data['review'], data['category'], data['sentiment']
                    input = torch.zeros(1,review_tensor.shape[2]).to(self.dl_studio.device)
                    hidden = net.init_hidden().to(self.dl_studio.device)
                    for k in range(review_tensor.shape[1]):
                        input[0,:] = review_tensor[0,k]
                        output, hidden, cell = net(input, hidden, cell_prev_2_prev)
                        if k == 0:
                            cell_prev = cell
                        else:
                            cell_prev_2_prev = cell_prev
                            cell_prev = cell
                    predicted_idx = torch.argmax(output).item()
                    gt_idx = torch.argmax(sentiment).item()
                    if i % 100 == 99:
                        print("   [i=%4d]    predicted_label=%d       gt_label=%d" % (i+1, predicted_idx,gt_idx))
                    if predicted_idx == gt_idx:
                        classification_accuracy += 1
                    if gt_idx == 0: 
                        negative_total += 1
                    elif gt_idx == 1:
                        positive_total += 1
                    confusion_matrix[gt_idx,predicted_idx] += 1
            print("\nOverall classification accuracy: %0.2f%%" %  (float(classification_accuracy) * 100 /float(i)))
            out_percent = np.zeros((2,2), dtype='float')
            out_percent[0,0] = "%.3f" % (100 * confusion_matrix[0,0] / float(negative_total))
            out_percent[0,1] = "%.3f" % (100 * confusion_matrix[0,1] / float(negative_total))
            out_percent[1,0] = "%.3f" % (100 * confusion_matrix[1,0] / float(positive_total))
            out_percent[1,1] = "%.3f" % (100 * confusion_matrix[1,1] / float(positive_total))
            print("\n\nNumber of positive reviews tested: %d" % positive_total)
            print("\n\nNumber of negative reviews tested: %d" % negative_total)
            print("\n\nDisplaying the confusion matrix:\n")
            out_str = "                      "
            out_str +=  "%18s    %18s" % ('predicted negative', 'predicted positive')
            print(out_str + "\n")
            for i,label in enumerate(['true negative', 'true positive']):
                out_str = "%12s:  " % label
                for j in range(2):
                    out_str +=  "%18s" % out_percent[i,j]
                print(out_str)


        def run_code_for_testing_text_classification_with_GRU_word2vec(self, net):
            net.load_state_dict(torch.load(self.dl_studio.path_saved_model))
            classification_accuracy = 0.0
            negative_total = 0
            positive_total = 0
            confusion_matrix = torch.zeros(2,2)
            with torch.no_grad():
                for i, data in enumerate(self.test_dataloader):
                    review_tensor,category,sentiment = data['review'], data['category'], data['sentiment']
                    hidden = net.init_hidden()
                    for k in range(review_tensor.shape[1]):
                        output, hidden = net(torch.unsqueeze(torch.unsqueeze(review_tensor[0,k],0),0), hidden)
                    predicted_idx = torch.argmax(output).item()
                    gt_idx = torch.argmax(sentiment).item()
                    if i % 100 == 99:
                        print("   [i=%d]    predicted_label=%d       gt_label=%d" % (i+1, predicted_idx,gt_idx))
                    if predicted_idx == gt_idx:
                        classification_accuracy += 1
                    if gt_idx == 0: 
                        negative_total += 1
                    elif gt_idx == 1:
                        positive_total += 1
                    confusion_matrix[gt_idx,predicted_idx] += 1
            print("\nOverall classification accuracy: %0.2f%%" %  (float(classification_accuracy) * 100 /float(i)))
            out_percent = np.zeros((2,2), dtype='float')
            out_percent[0,0] = "%.3f" % (100 * confusion_matrix[0,0] / float(negative_total))
            out_percent[0,1] = "%.3f" % (100 * confusion_matrix[0,1] / float(negative_total))
            out_percent[1,0] = "%.3f" % (100 * confusion_matrix[1,0] / float(positive_total))
            out_percent[1,1] = "%.3f" % (100 * confusion_matrix[1,1] / float(positive_total))
            print("\n\nNumber of positive reviews tested: %d" % positive_total)
            print("\n\nNumber of negative reviews tested: %d" % negative_total)
            print("\n\nDisplaying the confusion matrix:\n")
            out_str = "                      "
            out_str +=  "%18s    %18s" % ('predicted negative', 'predicted positive')
            print(out_str + "\n")
            for i,label in enumerate(['true negative', 'true positive']):
                out_str = "%12s:  " % label
                for j in range(2):
                    out_str +=  "%18s%%" % out_percent[i,j]
                print(out_str)


#_________________________  End of DLStudio Class Definition ___________________________

#______________________________    Test code follows    _________________________________

if __name__ == '__main__': 
    pass