dataset is MNIST
# Imports
import torch
import torch.nn as nn # All neural network modules, nn.Linear, nn.Conv2d, BatchNorm, Loss functions
import torch.optim as optim # For all Optimization algorithms, SGD, Adam, etc.
import torch.nn.functional as F # All functions that don't have any parameters
from torch.utils.data import DataLoader # Gives easier dataset management and creates mini batches
import torchvision.datasets as datasets # Has standard datasets we can import in a nice way
import torchvision.transforms as transforms # Transformations we can perform on our dataset
# Create Simple Fully Connected Neural Network
class NN(nn.Module):
def __init__(self,input_size,num_classes):
super(NN, self).__init__()
self.fc1 = nn.Linear(input_size,50)
self.fc2 = nn.Linear(50,num_classes)
def forward(self,x):
x = F.relu(self.fc1(x))
x = self.fc2(x)
return x
# model = NN(784,10)
# x = torch.randn(64,784)
# print(model(x).shape)
# Set device
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
# Hyperparameters
input_size = 784 # 28*28
num_classes = 10
learning_rate = 1e-3
batch_size = 64
num_epochs = 1
# Load Data
train_dataset = datasets.MNIST("../",train=True,transform=transforms.ToTensor(),download=True)
test_dataset = datasets.MNIST("../",train=False,transform=transforms.ToTensor(),download=True)
train_loader = DataLoader(dataset=train_dataset,batch_size=batch_size,shuffle=True)
test_loader = DataLoader(dataset=test_dataset,batch_size=batch_size,shuffle=True)
# Initialize network
model = NN(input_size=input_size,num_classes=num_classes).to(device=device)
# Initialize network
criterion = nn.CrossEntropyLoss()
optimizer = optim.Adam(params=model.parameters(),lr=learning_rate)
# Train Network
for epoch in range(num_epochs):
for batch_idx,(data,targets) in enumerate(train_loader):
# Get data to cuda if possible
data = data.to(device)
targets = targets.to(device)
# print(data.shape)
# Get to correct shape
data = data.reshape(data.shape[0],-1)
# forward
scores = model(data)
loss = criterion(scores,targets)
# backward
optimizer.zero_grad()
loss.backward()
# gradient descent or adam step
optimizer.step()
# Check accuracy on training & test to see how good our model
def check_accuracy(loader,model):
if loader.dataset.train:
print("Checking accuracy on training data")
else:
print("Checking accuracy on testing data")
num_correct = 0
num_samples = 0
model.eval()
with torch.no_grad():
for x,y in loader:
x = x.to(device)
y = y.to(device)
x = x.reshape(x.shape[0],-1)
scores = model(x)
_, predictions = scores.max(1)
num_correct += (predictions==y).sum()
num_samples += predictions.size(0)
print(f'Got {
num_correct}/{
num_samples} with accuracy {
float(num_correct)/float(num_samples)*100:.2f}')
model.train()
check_accuracy(train_loader,model)
check_accuracy(test_loader,model)