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机器学习代写|CSCE 421 Machine Learning Homework 6 (HW-6) Spring 2023

机器学习代写|CSCE 421 Machine Learning Homework 6 (HW-6) Spring 2023

这是一篇来自美国的关于从头开始编码一个卷积神经网络,以便使用PyTorch对图像进行分类的机器学习代写

 

Convolutional Neural Networks

In this assignment, you’ll be coding up a convolutional neural network from scratch to classify images using PyTorch.

Instructions

Install PyTorch following the instructions here (https://pytorch.org/).

Install the torchinfo package (https://github.com/TylerYep/torchinfo) to visualize the network architecture and the number of parameters. The maximum number of parameters you are allowed to use for your network is 100,000.

You are required to complete the functions defined in the code blocks following each question. Fill out sections of the code marked “YOUR CODE HERE” .

You’re free to add any number of methods within each class.

You may also add any number of additional code blocks that you deem necessary.

Once you’ve filled out your solutions, submit the notebook on Canvas.

Do NOT forget to type in your name and UIN at the beginning of the notebook.

Data Preparation

In [ ]:

!pip install torchinfo

In [ ]:

# Importing the libraries

import os

import torch

import torchvision

from torchvision.utils import make_grid

import numpy as np

In this assignment, we will use the Fashion-MNIST dataset. Fashion-MNIST is a dataset of Zalando’s article images—consisting of a training set of 60,000 examples and a test set of 10,000 examples. Each example is a 28×28 grayscale image, associated with a label from 10 classes.Data

Each image is 28 pixels in height and 28 pixels in width, for a total of 784 pixels in total. Each pixel has a single pixel-value associated with it, indicating the lightness or darkness of that pixel, with higher numbers meaning darker. This pixel-value is an integer between 0 and 255.

Labels

Each training and test example is assigned to one of the following labels:

Label Description

0 T-shirt/top

1 Trouser

2 Pullover

3 Dress

4 Coat

5 Sandal

6 Shirt

7 Sneaker

8 Bag

9 Ankle boot

Fashion-MNIST is included in the torchvision library.

In [ ]:

In [ ]:

Data Exploration

Let’s take a look at the classes in our dataset.

In [ ]:

from torchvision.datasets import FashionMNIST

from torchvision.transforms import Compose, ToTensor, Normalize

# Transform to normalize the data and convert to a tensor

transform = Compose([ToTensor(),

Normalize((0.5,), (0.5,))

])

# Download the data

dataset = FashionMNIST(‘MNIST_data/’, download = True, train = True, transform = transform)

print(dataset.classes)In [ ]:

import matplotlib.pyplot as plt

def show_example(img, label):

print(‘Label: {} ({})’.format(dataset.classes[label], label))

plt.imshow(img.squeeze(), cmap=’Greys_r’)

plt.axis(False)

In [ ]:

show_example(*dataset[20])

In [ ]:

show_example(*dataset[20000])

Creating Training and Validation Datasets

The split_indices function takes in the size of the entire dataset, n , the fraction of data to be used as validation set, val_frac , and the random seed and returns the indices of the data points to be added to the validation dataset.

Choose a suitable fraction for your validation set and experiment with the seed. Remember that the better your validation set, the higher the chances that your model would do well on the test set.

In [ ]:

def split_indices(n, val_frac, seed):

# Determine the size of the validation set

n_val = int(val_frac * n)

np.random.seed(seed)

# Create random permutation between 0 to n-1

idxs = np.random.permutation(n)

# Pick first n_val indices for validation set

return idxs[n_val:], idxs[:n_val]

In [ ]:

######################

# YOUR CODE BELOW #

######################

val_frac = ## Set the fraction for the validation set

rand_seed = ## Set the random seed

train_indices, val_indices = split_indices(len(dataset), val_frac, rand_seed)

print(“#samples in training set: {}”.format(len(train_indices)))

print(“#samples in validation set: {}”.format(len(val_indices)))

Next, we make use of the built-in dataloaders in PyTorch to create iterables of our our training and validation sets. This helps in avoiding fitting the whole dataset into memory and only loads a batch of the data that we can decide.Set the batch_size depending on the hardware resource (GPU/CPU RAM) you are using for the assignment

In [ ]:

from torch.utils.data.sampler import SubsetRandomSampler

from torch.utils.data.dataloader import DataLoader

In [ ]:

######################

# YOUR CODE BELOW #

######################

batch_size = ## Set the batch size

In [ ]:

# Training sampler and data loader

train_sampler = SubsetRandomSampler(train_indices)

train_dl = DataLoader(dataset,

batch_size,

sampler=train_sampler)

# Validation sampler and data loader

val_sampler = SubsetRandomSampler(val_indices)

val_dl = DataLoader(dataset,

batch_size,

sampler=val_sampler)

Plot images in a sample batch of data.

In [ ]:

def show_batch(dl):

for images, labels in dl:

fig, ax = plt.subplots(figsize=(10,10))

ax.set_xticks([]); ax.set_yticks([])

ax.imshow(make_grid(images, 8).permute(1, 2, 0), cmap=’Greys_r’)

break

In [ ]:

show_batch(train_dl)

Building the Model

Grading: 20 pts for Build the Model section

They don’t have to have the exact same model, e.g., the number of layers can be different, the parameters in the model

The very first parameter of the first layer has to be 1 nn.Conv2d(1, ….), because this is black-white dataset, otherwise -5pts

The very last parameter of the last layer has to be 10 nn.Linear(…, 10), otherwise -20pts.using nn.Conv1d (if ever happens) -20pts.

M P

l2d 10

Create your model by defining the network architecture in the ImageClassifierNet class.

NOTE: The number of parameters in your network must be 100,000.

In [ ]:

In [ ]:

In [ ]:

The following code block prints your network architecture. It also shows the total number of parameters inyour network (see Total params ).

NOTE: The total number of parameters in your model should be <= 100,000.

In [ ]:

##Check Model Requirements status

Below code cell is to check if your model meets the requirements specefied

Run the cell to check the status of your model

# Import the libraries

import torch.nn as nn

import torch.nn.functional as F

from torchinfo import summary

class ImageClassifierNet(nn.Module):

def __init__(self, n_channels=3):

super(ImageClassifierNet, self).__init__()

######################

# YOUR CODE HERE #

######################

def forward(self, X):

######################

# YOUR CODE HERE #

######################

model = ImageClassifierNet()

summary(model, input_size=(batch_size, 1, 28, 28))

In [ ]:

def check_model(model):

first_layer = list(model.children())[0]

last_layer = list(model.children())[-1]

num_params = sum(p.numel() for p in model.parameters())

has_conv1d = False

has_maxpool2d = False

first_layer_status= False

last_layer_status = False

if isinstance(first_layer, nn.Sequential):

if isinstance(first_layer[0], nn.Conv2d) and first_layer[0].in_channels == 1:

first_layer_status= True

else:

if isinstance(first_layer, nn.Conv2d) and first_layer.in_channels == 1:

first_layer_status= True

if isinstance(last_layer, nn.Sequential):

if isinstance(last_layer[-1], nn.Linear) and last_layer[-1].out_features == 10:

last_layer_status = True

else:

print(type(last_layer))

if isinstance(last_layer, nn.Linear) and last_layer.out_features == 10:

last_layer_status = True

for layer in model.modules():

if isinstance(layer, nn.Conv1d):

has_conv1d = True

if isinstance(layer, nn.MaxPool2d):

has_maxpool2d = True

flag = False

if first_layer_status == False:

print(“The very first parameter of the first layer is not 1 nn.Conv2d(1, ….)”)

flag = True

if last_layer_status == False:

print(“The very last parameter of the last layer is not 10 nn.Linear(…, 10)”)

flag = True

if has_conv1d == True:

print(“Using nn.Conv1d, which should not happen”)

flag = True

if has_maxpool2d == False:

print(“No nn.MaxPool2d”)

flag = True

if num_params > 100000:

print(“Parameters > 100000, please make the network less complex to recieve full grade”)

if flag == False:

print(“The Network looks good”)

check_model(model)

Enable training on a GPU

NOTE: This section is necessary if you’re training your model on a GPU.

bestdaixie

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