Open In Colab

Deep Learning Models: A collection of various deep learning architectures, models, & their implementations (PyTorch or TensorFlow) in Jupyter Notebooks.

  • Author: Chizoba Obasi
  • Github Repo: https://github.com/chizkidd/deep-learning-models
In [1]:
!pip install watermark
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In [2]:
!pip install torchinfo
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In [3]:
%load_ext watermark
# %reload_ext watermark
%watermark -a 'Chizoba Obasi' -v -p torch
Author: Chizoba Obasi

Python implementation: CPython
Python version       : 3.12.12
IPython version      : 7.34.0

torch: 2.9.0+cu126

ShuffleNetV2 Classifier on CIFAR-10¶

Network Architecture:

The network in this notebook is an implementation of the ShuffleNetV2 [1] architecture on the CIFAR-10 dataset to train an image classifier.

ShuffleNetV1-architecture

Image Source


ShuffleNetV2: Unit Block¶

ShuffleNetV2 Unit-block

Image Source




REFERENCES:

  1. Ma, N., Zhang, X., Zheng, H. T., & Sun, J. (2018). ShuffleNet V2: Practical Guidelines for Efficient CNN Architecture Design. In Proceedings of the European Conference on Computer Vision (ECCV) (pp. 116-131).
  2. Johnson, J. (2022, February 2). Lecture 11: CNN Architectures II [PowerPoint Slides]. University of Michigan EECS 498/598: Deep Learning for Computer Vision. pp 54-59. https://web.eecs.umich.edu/~justincj/slides/eecs498/WI2022/598_WI2022_lecture11.pdf
In [4]:
import torch
import torchvision
import torch.nn as nn
import torch.nn.functional as F
import torch.optim as optim
from torch.utils.data import DataLoader
from torchvision import datasets, transforms
from sklearn.model_selection import train_test_split

from torchinfo import summary

import matplotlib.image as mpimg
import matplotlib.pyplot as plt
%matplotlib inline

import pandas as pd
import numpy as np
import math
import time
import os
import random

if torch.cuda.is_available():
    torch.backends.cudnn.deterministic = True
In [5]:
def set_all_seeds(seed):
    os.environ["PL_GLOBAL_SEED"] = str(seed)
    random.seed(seed)
    np.random.seed(seed)
    torch.manual_seed(seed)
    torch.cuda.manual_seed_all(seed)

def set_deterministic():
    if torch.cuda.is_available():
        torch.backends.cudnn.benchmark = False
        torch.backends.cudnn.deterministic = True
    torch.set_deterministic(True)
In [6]:
# Check if GPU is available and set the device
if torch.cuda.is_available():
    num_gpus = torch.cuda.device_count()
    print("Num GPUs Available: ", num_gpus)
    for i in range(num_gpus):
        gpu_name = torch.cuda.get_device_name(i)
        print(f"GPU {i}: {gpu_name}")
else:
    print("No GPU available.")
Num GPUs Available:  1
GPU 0: Tesla T4

0. Model Hyperparameters¶


In [7]:
##########################
### SETTINGS
##########################

# Hyperparameters
RANDOM_SEED = 123
BATCH_SIZE = 128 #256
LEARNING_RATE = 0.001
NUM_EPOCHS = 30
INPUT_SIZE = 32 # CIFAR-10 is 32x32
NUM_CLASSES = 10

# Set device
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
print(device)
cuda
In [8]:
set_all_seeds(RANDOM_SEED)

1. Data Preparation & Loading¶


In [9]:
# Mean and Std Dev for CIFAR-10 (3 channels)
CIFAR_MEAN = (0.4914, 0.4822, 0.4465)
CIFAR_STD = (0.2471, 0.2435, 0.2616)

# Data Augmentation (Crucial for VGG-16 on CIFAR-10)
train_transforms = transforms.Compose([
    transforms.RandomCrop(32, padding=4),   # Crop after padding
    transforms.RandomHorizontalFlip(),      # Flip
    transforms.ToTensor(),
    transforms.Normalize(CIFAR_MEAN, CIFAR_STD) # Mean Subtraction
])

# Test/Validation Transforms (No Augmentation)
test_transforms = transforms.Compose([
    transforms.ToTensor(),
    transforms.Normalize(CIFAR_MEAN, CIFAR_STD)
])

# Load Datasets
train_dataset = datasets.CIFAR10(root='./data', train=True, download=True, transform=train_transforms)
test_dataset = datasets.CIFAR10(root='./data', train=False, download=True, transform=test_transforms)

# Split training set into training and validation sets
train_size = int(0.9 * len(train_dataset))
val_size = len(train_dataset) - train_size
train_subset, val_subset = torch.utils.data.random_split(train_dataset, [train_size, val_size])

# Create DataLoaders
train_loader = DataLoader(train_subset, batch_size=BATCH_SIZE, shuffle=True, num_workers=2, pin_memory=True)
val_loader = DataLoader(val_subset, batch_size=BATCH_SIZE, shuffle=False, num_workers=2, pin_memory=True)
test_loader = DataLoader(test_dataset, batch_size=BATCH_SIZE, shuffle=False, num_workers=2, pin_memory=True)
In [10]:
# Check that shuffling works properly
# i.e., label indices should be in random order.
# Also, the label order should be different in the second
# epoch.

for images, labels in train_loader:
    pass
print(labels[:10])

for images, labels in train_loader:
    pass
print(labels[:10])
tensor([1, 5, 5, 4, 2, 8, 5, 2, 4, 2])
tensor([9, 2, 4, 3, 7, 5, 8, 6, 2, 8])
In [11]:
# Check that validation set and test sets are diverse
# i.e., that they contain all classes

for images, labels in val_loader:
    pass
print(labels[:10])

for images, labels in test_loader:
    pass
print(labels[:10])
tensor([1, 6, 5, 9, 9, 0, 6, 6])
tensor([7, 5, 8, 0, 8, 2, 7, 0, 3, 5])

2. Model Creation¶


In [12]:
def channel_shuffle(x, groups):
    batchsize, num_channels, height, width = x.data.size()
    channels_per_group = num_channels // groups
    x = x.view(batchsize, groups, channels_per_group, height, width)
    x = torch.transpose(x, 1, 2).contiguous()
    x = x.view(batchsize, -1, height, width)
    return x

class ShuffleUnit(nn.Module):
    def __init__(self, in_channels, out_channels, stride):
        super(ShuffleUnit, self).__init__()
        self.stride = stride
        mid_channels = out_channels // 2

        if stride > 1:
            self.branch1 = nn.Sequential(
                nn.Conv2d(in_channels, in_channels, 3, stride, 1, groups=in_channels, bias=False),
                nn.BatchNorm2d(in_channels),
                nn.Conv2d(in_channels, mid_channels, 1, 1, 0, bias=False),
                nn.BatchNorm2d(mid_channels),
                nn.ReLU(inplace=True)
            )
        else:
            self.branch1 = nn.Sequential()

        self.branch2 = nn.Sequential(
            nn.Conv2d(in_channels if stride > 1 else mid_channels, mid_channels, 1, 1, 0, bias=False),
            nn.BatchNorm2d(mid_channels),
            nn.ReLU(inplace=True),
            nn.Conv2d(mid_channels, mid_channels, 3, stride, 1, groups=mid_channels, bias=False),
            nn.BatchNorm2d(mid_channels),
            nn.Conv2d(mid_channels, mid_channels, 1, 1, 0, bias=False),
            nn.BatchNorm2d(mid_channels),
            nn.ReLU(inplace=True)
        )

    def forward(self, x):
        if self.stride > 1:
            x = torch.cat((self.branch1(x), self.branch2(x)), dim=1)
        else:
            x1, x2 = x.chunk(2, dim=1)
            x = torch.cat((x1, self.branch2(x2)), dim=1)
        return channel_shuffle(x, 2)

class ShuffleNetV2(nn.Module):
    def __init__(self, net_size=1.0):
        super(ShuffleNetV2, self).__init__()
        # Config for ShuffleNetV2 1.0x
        out_channels = [24, 116, 232, 464, 1024]

        # Initial layer: modified for CIFAR (3x3 conv instead of 7x7)
        self.conv1 = nn.Sequential(
            nn.Conv2d(3, out_channels[0], 3, 1, 1, bias=False),
            nn.BatchNorm2d(out_channels[0]),
            nn.ReLU(inplace=True)
        )

        self.stage2 = self._make_stage(out_channels[0], out_channels[1], 4, 2)
        self.stage3 = self._make_stage(out_channels[1], out_channels[2], 8, 2)
        self.stage4 = self._make_stage(out_channels[2], out_channels[3], 4, 2)

        self.conv5 = nn.Sequential(
            nn.Conv2d(out_channels[3], out_channels[4], 1, 1, 0, bias=False),
            nn.BatchNorm2d(out_channels[4]),
            nn.ReLU(inplace=True)
        )

        self.fc = nn.Linear(out_channels[4], 10)

    def _make_stage(self, in_channels, out_channels, repeats, stride):
        layers = [ShuffleUnit(in_channels, out_channels, stride)]
        for _ in range(repeats - 1):
            layers.append(ShuffleUnit(out_channels, out_channels, 1))
        return nn.Sequential(*layers)

    def forward(self, x):
        x = self.conv1(x)
        x = self.stage2(x)
        x = self.stage3(x)
        x = self.stage4(x)
        x = self.conv5(x)
        x = F.adaptive_avg_pool2d(x, (1, 1))
        x = x.view(x.size(0), -1)
        x = self.fc(x)
        return x

model = ShuffleNetV2().to(device)
In [13]:
model = ShuffleNetV2().to(device)
In [14]:
# Model parameter details
summary(model,
        input_size=(BATCH_SIZE, 3, INPUT_SIZE, INPUT_SIZE),
        # verbose=1,
        col_names=["input_size", "output_size", "num_params", "kernel_size", "mult_adds"]
       )
Out[14]:
=====================================================================================================================================================================
Layer (type:depth-idx)                   Input Shape               Output Shape              Param #                   Kernel Shape              Mult-Adds
=====================================================================================================================================================================
ShuffleNetV2                             [128, 3, 32, 32]          [128, 10]                 --                        --                        --
├─Sequential: 1-1                        [128, 3, 32, 32]          [128, 24, 32, 32]         --                        --                        --
│    └─Conv2d: 2-1                       [128, 3, 32, 32]          [128, 24, 32, 32]         648                       [3, 3]                    84,934,656
│    └─BatchNorm2d: 2-2                  [128, 24, 32, 32]         [128, 24, 32, 32]         48                        --                        6,144
│    └─ReLU: 2-3                         [128, 24, 32, 32]         [128, 24, 32, 32]         --                        --                        --
├─Sequential: 1-2                        [128, 24, 32, 32]         [128, 116, 16, 16]        --                        --                        --
│    └─ShuffleUnit: 2-4                  [128, 24, 32, 32]         [128, 116, 16, 16]        --                        --                        --
│    │    └─Sequential: 3-1              [128, 24, 32, 32]         [128, 58, 16, 16]         1,772                     --                        52,711,936
│    │    └─Sequential: 3-2              [128, 24, 32, 32]         [128, 58, 16, 16]         5,626                     --                        309,833,216
│    └─ShuffleUnit: 2-5                  [128, 116, 16, 16]        [128, 116, 16, 16]        --                        --                        --
│    │    └─Sequential: 3-3              [128, 58, 16, 16]         [128, 58, 16, 16]         7,598                     --                        237,612,544
│    └─ShuffleUnit: 2-6                  [128, 116, 16, 16]        [128, 116, 16, 16]        --                        --                        --
│    │    └─Sequential: 3-4              [128, 58, 16, 16]         [128, 58, 16, 16]         7,598                     --                        237,612,544
│    └─ShuffleUnit: 2-7                  [128, 116, 16, 16]        [128, 116, 16, 16]        --                        --                        --
│    │    └─Sequential: 3-5              [128, 58, 16, 16]         [128, 58, 16, 16]         7,598                     --                        237,612,544
├─Sequential: 1-3                        [128, 116, 16, 16]        [128, 232, 8, 8]          --                        --                        --
│    └─ShuffleUnit: 2-8                  [128, 116, 16, 16]        [128, 232, 8, 8]          --                        --                        --
│    │    └─Sequential: 3-6              [128, 116, 16, 16]        [128, 116, 8, 8]          14,964                    --                        118,843,392
│    │    └─Sequential: 3-7              [128, 116, 16, 16]        [128, 116, 8, 8]          28,652                    --                        559,799,296
│    └─ShuffleUnit: 2-9                  [128, 232, 8, 8]          [128, 232, 8, 8]          --                        --                        --
│    │    └─Sequential: 3-8              [128, 116, 8, 8]          [128, 116, 8, 8]          28,652                    --                        229,104,640
│    └─ShuffleUnit: 2-10                 [128, 232, 8, 8]          [128, 232, 8, 8]          --                        --                        --
│    │    └─Sequential: 3-9              [128, 116, 8, 8]          [128, 116, 8, 8]          28,652                    --                        229,104,640
│    └─ShuffleUnit: 2-11                 [128, 232, 8, 8]          [128, 232, 8, 8]          --                        --                        --
│    │    └─Sequential: 3-10             [128, 116, 8, 8]          [128, 116, 8, 8]          28,652                    --                        229,104,640
│    └─ShuffleUnit: 2-12                 [128, 232, 8, 8]          [128, 232, 8, 8]          --                        --                        --
│    │    └─Sequential: 3-11             [128, 116, 8, 8]          [128, 116, 8, 8]          28,652                    --                        229,104,640
│    └─ShuffleUnit: 2-13                 [128, 232, 8, 8]          [128, 232, 8, 8]          --                        --                        --
│    │    └─Sequential: 3-12             [128, 116, 8, 8]          [128, 116, 8, 8]          28,652                    --                        229,104,640
│    └─ShuffleUnit: 2-14                 [128, 232, 8, 8]          [128, 232, 8, 8]          --                        --                        --
│    │    └─Sequential: 3-13             [128, 116, 8, 8]          [128, 116, 8, 8]          28,652                    --                        229,104,640
│    └─ShuffleUnit: 2-15                 [128, 232, 8, 8]          [128, 232, 8, 8]          --                        --                        --
│    │    └─Sequential: 3-14             [128, 116, 8, 8]          [128, 116, 8, 8]          28,652                    --                        229,104,640
├─Sequential: 1-4                        [128, 232, 8, 8]          [128, 464, 4, 4]          --                        --                        --
│    └─ShuffleUnit: 2-16                 [128, 232, 8, 8]          [128, 464, 4, 4]          --                        --                        --
│    │    └─Sequential: 3-15             [128, 232, 8, 8]          [128, 232, 4, 4]          56,840                    --                        114,626,560
│    │    └─Sequential: 3-16             [128, 232, 8, 8]          [128, 232, 4, 4]          111,128                   --                        555,612,160
│    └─ShuffleUnit: 2-17                 [128, 464, 4, 4]          [128, 464, 4, 4]          --                        --                        --
│    │    └─Sequential: 3-17             [128, 232, 4, 4]          [128, 232, 4, 4]          111,128                   --                        224,917,504
│    └─ShuffleUnit: 2-18                 [128, 464, 4, 4]          [128, 464, 4, 4]          --                        --                        --
│    │    └─Sequential: 3-18             [128, 232, 4, 4]          [128, 232, 4, 4]          111,128                   --                        224,917,504
│    └─ShuffleUnit: 2-19                 [128, 464, 4, 4]          [128, 464, 4, 4]          --                        --                        --
│    │    └─Sequential: 3-19             [128, 232, 4, 4]          [128, 232, 4, 4]          111,128                   --                        224,917,504
├─Sequential: 1-5                        [128, 464, 4, 4]          [128, 1024, 4, 4]         --                        --                        --
│    └─Conv2d: 2-20                      [128, 464, 4, 4]          [128, 1024, 4, 4]         475,136                   [1, 1]                    973,078,528
│    └─BatchNorm2d: 2-21                 [128, 1024, 4, 4]         [128, 1024, 4, 4]         2,048                     --                        262,144
│    └─ReLU: 2-22                        [128, 1024, 4, 4]         [128, 1024, 4, 4]         --                        --                        --
├─Linear: 1-6                            [128, 1024]               [128, 10]                 10,250                    --                        1,312,000
=====================================================================================================================================================================
Total params: 1,263,854
Trainable params: 1,263,854
Non-trainable params: 0
Total mult-adds (Units.GIGABYTES): 5.76
=====================================================================================================================================================================
Input size (MB): 1.57
Forward/backward pass size (MB): 1153.18
Params size (MB): 5.06
Estimated Total Size (MB): 1159.81
=====================================================================================================================================================================

3. Model Training, Testing & Evaluation¶


In [15]:
criterion = nn.CrossEntropyLoss()
optimizer = optim.Adam(model.parameters(), lr=LEARNING_RATE, weight_decay=5e-4)
# optimizer = optim.SGD(model.parameters(), lr=LEARNING_RATE, momentum=0.9, weight_decay=5e-4) # Use weight decay (L2) to combat overfitting
# scheduler = optim.lr_scheduler.ReduceLROnPlateau(optimizer, mode='min', factor=0.1, patience=5)

def calculate_accuracy(loader):
    model.eval()
    correct = 0
    total = 0
    with torch.no_grad():
        for inputs, labels in loader:
            inputs, labels = inputs.to(device), labels.to(device)
            outputs = model(inputs)
            _, predicted = torch.max(outputs.data, 1)
            total += labels.size(0)
            correct += (predicted == labels).sum().item()
    return 100 * correct / total

# Training Loop
start_time = time.time()
history = {'train_loss': [], 'val_loss': [], 'train_acc': [], 'val_acc': [], 'lrs': []}

print(f"Starting training on {device}...")

for epoch in range(NUM_EPOCHS):
    model.train()
    running_loss = 0.0

    for i, (inputs, labels) in enumerate(train_loader):
        inputs, labels = inputs.to(device), labels.to(device)

        optimizer.zero_grad()
        outputs = model(inputs)
        loss = criterion(outputs, labels)
        loss.backward()
        optimizer.step()

        running_loss += loss.item() * inputs.size(0)

    train_loss = running_loss / len(train_subset)
    train_acc = calculate_accuracy(train_loader)

    # Calculate validation loss and accuracy
    model.eval()
    val_loss = 0.0
    with torch.no_grad():
        for inputs, labels in val_loader:
            inputs, labels = inputs.to(device), labels.to(device)
            outputs = model(inputs)
            loss = criterion(outputs, labels)
            val_loss += loss.item() * inputs.size(0)

    val_loss /= len(val_subset)
    val_acc = calculate_accuracy(val_loader)

    # scheduler.step(val_loss)
    # current_lr = optimizer.param_groups[0]['lr']

    # Log metrics
    history['train_loss'].append(train_loss)
    history['val_loss'].append(val_loss)
    history['train_acc'].append(train_acc)
    history['val_acc'].append(val_acc)
    # history['lrs'].append(current_lr)

    print(f'Epoch {epoch + 1}/{NUM_EPOCHS} | '
          f'Train Loss: {train_loss:.5f}, '
          f'Train Acc.: {train_acc:.2f}% | '
          f'Val Loss: {val_loss:.5f}, '
          f'Val Acc.: {val_acc:.2f}% | '
          # f'LR: {current_lr:.8f}')
         )

print('\nTotal Training Time: %.2f min' % ((time.time() - start_time)/60))

# --- Final Evaluation ---
test_accuracy = calculate_accuracy(test_loader)
print(f'\nTest Accuracy: {test_accuracy:.2f}%')
Starting training on cuda...
Epoch 1/30 | Train Loss: 1.71806, Train Acc.: 45.01% | Val Loss: 1.53539, Val Acc.: 43.18% | 
Epoch 2/30 | Train Loss: 1.36425, Train Acc.: 53.28% | Val Loss: 1.32741, Val Acc.: 51.80% | 
Epoch 3/30 | Train Loss: 1.17134, Train Acc.: 61.79% | Val Loss: 1.12907, Val Acc.: 59.54% | 
Epoch 4/30 | Train Loss: 1.01715, Train Acc.: 67.34% | Val Loss: 0.97544, Val Acc.: 64.70% | 
Epoch 5/30 | Train Loss: 0.88393, Train Acc.: 70.49% | Val Loss: 0.90727, Val Acc.: 68.18% | 
Epoch 6/30 | Train Loss: 0.79267, Train Acc.: 74.53% | Val Loss: 0.80005, Val Acc.: 71.64% | 
Epoch 7/30 | Train Loss: 0.72289, Train Acc.: 76.02% | Val Loss: 0.75722, Val Acc.: 73.96% | 
Epoch 8/30 | Train Loss: 0.66590, Train Acc.: 77.69% | Val Loss: 0.72508, Val Acc.: 74.36% | 
Epoch 9/30 | Train Loss: 0.62746, Train Acc.: 79.22% | Val Loss: 0.68530, Val Acc.: 75.80% | 
Epoch 10/30 | Train Loss: 0.59550, Train Acc.: 81.06% | Val Loss: 0.61650, Val Acc.: 78.56% | 
Epoch 11/30 | Train Loss: 0.56085, Train Acc.: 81.91% | Val Loss: 0.61428, Val Acc.: 79.04% | 
Epoch 12/30 | Train Loss: 0.53128, Train Acc.: 81.10% | Val Loss: 0.63547, Val Acc.: 77.82% | 
Epoch 13/30 | Train Loss: 0.50932, Train Acc.: 83.14% | Val Loss: 0.60744, Val Acc.: 78.82% | 
Epoch 14/30 | Train Loss: 0.49018, Train Acc.: 84.76% | Val Loss: 0.54207, Val Acc.: 81.48% | 
Epoch 15/30 | Train Loss: 0.47403, Train Acc.: 84.88% | Val Loss: 0.54331, Val Acc.: 81.22% | 
Epoch 16/30 | Train Loss: 0.45681, Train Acc.: 84.48% | Val Loss: 0.55351, Val Acc.: 80.74% | 
Epoch 17/30 | Train Loss: 0.44454, Train Acc.: 84.96% | Val Loss: 0.53899, Val Acc.: 81.22% | 
Epoch 18/30 | Train Loss: 0.43036, Train Acc.: 85.88% | Val Loss: 0.53128, Val Acc.: 82.26% | 
Epoch 19/30 | Train Loss: 0.42551, Train Acc.: 87.16% | Val Loss: 0.47808, Val Acc.: 82.84% | 
Epoch 20/30 | Train Loss: 0.41200, Train Acc.: 86.05% | Val Loss: 0.52619, Val Acc.: 82.16% | 
Epoch 21/30 | Train Loss: 0.40151, Train Acc.: 87.26% | Val Loss: 0.48380, Val Acc.: 83.02% | 
Epoch 22/30 | Train Loss: 0.39145, Train Acc.: 87.90% | Val Loss: 0.46954, Val Acc.: 84.22% | 
Epoch 23/30 | Train Loss: 0.38501, Train Acc.: 88.05% | Val Loss: 0.47825, Val Acc.: 83.68% | 
Epoch 24/30 | Train Loss: 0.37875, Train Acc.: 88.34% | Val Loss: 0.47442, Val Acc.: 83.78% | 
Epoch 25/30 | Train Loss: 0.36723, Train Acc.: 88.56% | Val Loss: 0.44377, Val Acc.: 84.96% | 
Epoch 26/30 | Train Loss: 0.36346, Train Acc.: 88.84% | Val Loss: 0.45547, Val Acc.: 84.20% | 
Epoch 27/30 | Train Loss: 0.35831, Train Acc.: 88.59% | Val Loss: 0.45321, Val Acc.: 84.82% | 
Epoch 28/30 | Train Loss: 0.35466, Train Acc.: 89.62% | Val Loss: 0.45734, Val Acc.: 84.76% | 
Epoch 29/30 | Train Loss: 0.35032, Train Acc.: 89.33% | Val Loss: 0.44144, Val Acc.: 85.06% | 
Epoch 30/30 | Train Loss: 0.33981, Train Acc.: 89.79% | Val Loss: 0.43944, Val Acc.: 85.68% | 

Total Training Time: 23.84 min

Test Accuracy: 86.08%
In [16]:
# --- Final Evaluation ---
test_accuracy = calculate_accuracy(test_loader)
print(f'\nTest Accuracy: {test_accuracy:.2f}%')
Test Accuracy: 86.08%
In [17]:
def plot_history(history):
    """
    Plots the training and validation loss, accuracy, and learning rate
    from a PyTorch history dictionary.

    Args:
        history (dict): Dictionary containing training metrics.
                        Expected keys: 'train_loss', 'val_loss', 'train_acc', 'val_acc', 'lrs'.
    """
    epochs = range(len(history['train_loss']))

    plt.figure(figsize=(18, 5))

    # Plot 1: Loss
    plt.subplot(1, 3, 1)
    plt.plot(epochs, history['train_loss'], label='Training Loss')
    plt.plot(epochs, history['val_loss'], label='Validation Loss')
    plt.title('Loss')
    plt.xlabel('Epochs')
    plt.ylabel('Loss')
    plt.legend()
    # plt.grid(True)

    # Plot 2: Accuracy
    plt.subplot(1, 3, 2)
    plt.plot(epochs, history['train_acc'], label='Training Accuracy')
    plt.plot(epochs, history['val_acc'], label='Validation Accuracy')
    plt.title('Accuracy')
    plt.xlabel('Epochs')
    plt.ylabel('Accuracy')
    plt.legend()
    # plt.grid(True)

    plt.tight_layout()
    plt.show()
    # plt.savefig()

plot_history(history)
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In [18]:
from sklearn.metrics import confusion_matrix
import seaborn as sns

def _compute_confusion_matrix(model, data_loader, device):
    """
    Computes a confusion matrix for the given model and data.
    Uses scikit-learn for robustness and speed.
    """
    model.eval()
    all_targets = []
    all_predictions = []

    with torch.no_grad():
        for features, targets in data_loader:
            features = features.to(device)

            logits = model(features)
            _, predicted_labels = torch.max(logits, 1)

            # Move to CPU and convert to list/numpy immediately
            all_targets.extend(targets.view(-1).cpu().numpy())
            all_predictions.extend(predicted_labels.view(-1).cpu().numpy())

    return confusion_matrix(all_targets, all_predictions)

def _plot_confusion_matrix(mat, class_names):
    """
    Visualizes the confusion matrix using Seaborn for professional reporting.
    """
    plt.figure(figsize=(10, 8))
    sns.heatmap(mat, annot=True, fmt='d', cmap='Blues',
                xticklabels=class_names, yticklabels=class_names)
    plt.xlabel('Predicted Label')
    plt.ylabel('True Label')
    plt.title('Confusion Matrix: MobileNetV2 on CIFAR-10')
    plt.show()
In [19]:
class_dict = {0: 'plane',
              1: 'car',
              2: 'bird',
              3: 'cat',
              4: 'deer',
              5: 'dog',
              6: 'frog',
              7: 'horse',
              8: 'ship',
              9: 'truck'}
_mat = _compute_confusion_matrix(model=model, data_loader=test_loader, device=device)
_plot_confusion_matrix(_mat, class_names=class_dict.values())
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In [20]:
%watermark -iv
matplotlib : 3.10.0
numpy      : 2.0.2
pandas     : 2.2.2
seaborn    : 0.13.2
sklearn    : 1.6.1
torch      : 2.9.0+cu126
torchinfo  : 1.8.0
torchvision: 0.24.0+cu126

In [20]: