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Pytorch

[Pytorch] DNN을 이용한 MNIST

by xangmin 2021. 6. 7.
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라이브러리 Import하기

 Pytorch에서 Deep Neural Network(DNN)를 설계하기 위해 필요한 라이브러리를 Import한다.

#Importing Library

import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.optim as optim
from torchvision import datasets, transforms

 

DNN 모델

 MNIST 데이터는 28x28로 총 784개의 픽셀로 이루어져 있다. 그렇기 때문에 784를 입력 크기 값으로 받는다. 네트워크는 총 6개의 레이어로 이루어져 있으며 숫자의 종류(0~9)에 따라 마지막 출력단은 10개로 설정한다. 각각의 활성함수(activation function)은 linear를 사용하고 마지막 출력단에서 SoftMax의 확률을 통해 0부터 9사이의 숫자로 결정된다.

#Define Neural Networks Model.

class Net(nn.Module):
    def __init__(self):
        super(Net, self).__init__()
        self.fc1 = nn.Linear(784, 512)
        self.fc2 = nn.Linear(512, 256)
        self.fc3 = nn.Linear(256, 128)
        self.fc4 = nn.Linear(128, 64)
        self.fc5 = nn.Linear(64, 32)
        self.fc6 = nn.Linear(32, 10)

    def forward(self, x):
        x = x.float()
        h1 = F.relu(self.fc1(x.view(-1, 784)))
        h2 = F.relu(self.fc2(h1))
        h3 = F.relu(self.fc3(h2))
        h4 = F.relu(self.fc4(h3))
        h5 = F.relu(self.fc5(h4))
        h6 = self.fc6(h5)
        return F.log_softmax(h6, dim=1)

print("init model done")

 

하이퍼 파라미터 설정

아래와 같이 하이퍼 파라미터를 설정한다.

# Set Hyper parameters and other variables to train the model.

batch_size = 64
test_batch_size = 1000
epochs = 10
lr = 0.01
momentum = 0.5
no_cuda = True
seed = 1
log_interval = 200

use_cuda = not no_cuda and torch.cuda.is_available()
torch.manual_seed(seed)
device = torch.device("cuda" if use_cuda else "cpu")
kwargs = {'num_workers': 1, 'pin_memory': True} if use_cuda else {}
print("set vars and device done")

 

데이터 로드

 MNIST 데이터를 로드한다. 훈련 데이터는 6만개, 테스트 데이터는 1만개로 이루어져 있다.

#Prepare Data Loader for Training and Validation

transform = transforms.Compose([
                 transforms.ToTensor(),
                 transforms.Normalize((0.1307,), (0.3081,))])

train_loader = torch.utils.data.DataLoader(
  datasets.MNIST('../data', train=True, download=True, 
                 transform=transform), 
    batch_size = batch_size, shuffle=True, **kwargs)

test_loader = torch.utils.data.DataLoader(
        datasets.MNIST('../data', train=False, download=True,
                 transform=transform), 
    batch_size=test_batch_size, shuffle=True, **kwargs)

 

모델 불러오기 / 옵티마 선언

model = Net().to(device)
optimizer = optim.SGD(model.parameters(), lr=lr, momentum=momentum)

 

훈련 / 테스트 함수 구현

#Define Train function and Test function to validate.

def train(log_interval, model, device, train_loader, optimizer, epoch):
    model.train()
    for batch_idx, (data, target) in enumerate(train_loader):
        data, target = data.to(device), target.to(device)
        optimizer.zero_grad()
        output = model(data)
        loss = F.nll_loss(output, target)
        loss.backward()
        optimizer.step()
        if batch_idx % log_interval == 0:
            print('Train Epoch: {} [{}/{} ({:.0f}%)]\tLoss: {:.6f}'.format(
                epoch, batch_idx * len(data), len(train_loader.dataset),
                100. * batch_idx / len(train_loader), loss.item()))

def test(log_interval, model, device, test_loader):
    model.eval()
    test_loss = 0
    correct = 0
    with torch.no_grad():
        for data, target in test_loader:
            data, target = data.to(device), target.to(device)
            output = model(data)
            test_loss += F.nll_loss(output, target, reduction='sum').item() 
            pred = output.argmax(dim=1, keepdim=True)
            correct += pred.eq(target.view_as(pred)).sum().item()

    test_loss /= len(test_loader.dataset)

    print('\nTest set: Average loss: {:.4f}, Accuracy: {}/{} ({:.0f}%)\n'.format
          (test_loss, correct, len(test_loader.dataset),
        100. * correct / len(test_loader.dataset)))

 

네트워크 훈련 및 테스트 적용

 10 epoch동안 학습을 진행한다. 1epoch 학습을 진행할 때 마다 test를 진행한다.

# Train and Test the model and save it.

for epoch in range(1, 11):
    train(log_interval, model, device, train_loader, optimizer, epoch)
    test(log_interval, model, device, test_loader)
torch.save(model, './model.pt')

 

전체 코드

#Importing Library
import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.optim as optim
from torchvision import datasets, transforms


#Define Neural Networks Model.
class Net(nn.Module):
    def __init__(self):
        super(Net, self).__init__()
        self.fc1 = nn.Linear(784, 512)
        self.fc2 = nn.Linear(512, 256)
        self.fc3 = nn.Linear(256, 128)
        self.fc4 = nn.Linear(128, 64)
        self.fc5 = nn.Linear(64, 32)
        self.fc6 = nn.Linear(32, 10)

    def forward(self, x):
        x = x.float()
        h1 = F.relu(self.fc1(x.view(-1, 784)))
        h2 = F.relu(self.fc2(h1))
        h3 = F.relu(self.fc3(h2))
        h4 = F.relu(self.fc4(h3))
        h5 = F.relu(self.fc5(h4))
        h6 = self.fc6(h5)
        return F.log_softmax(h6, dim=1)
        
print("init model done")


# Set Hyper parameters and other variables to train the model.
batch_size = 64
test_batch_size = 1000
epochs = 10
lr = 0.01
momentum = 0.5
no_cuda = True
seed = 1
log_interval = 200

use_cuda = not no_cuda and torch.cuda.is_available()
torch.manual_seed(seed)
device = torch.device("cuda" if use_cuda else "cpu")
kwargs = {'num_workers': 1, 'pin_memory': True} if use_cuda else {}
print("set vars and device done")


#Prepare Data Loader for Training and Validation
transform = transforms.Compose([
                 transforms.ToTensor(),
                 transforms.Normalize((0.1307,), (0.3081,))])

train_loader = torch.utils.data.DataLoader(
  datasets.MNIST('../data', train=True, download=True,
                 transform=transform),
    batch_size = batch_size, shuffle=True, **kwargs)

test_loader = torch.utils.data.DataLoader(
        datasets.MNIST('../data', train=False, download=True,
                 transform=transform),
    batch_size=test_batch_size, shuffle=True, **kwargs)


model = Net().to(device)
optimizer = optim.SGD(model.parameters(), lr=lr, momentum=momentum)


#Define Train function and Test function to validate.
def train(log_interval, model, device, train_loader, optimizer, epoch):
    model.train()
    for batch_idx, (data, target) in enumerate(train_loader):
        data, target = data.to(device), target.to(device)
        optimizer.zero_grad()
        output = model(data)
        loss = F.nll_loss(output, target)
        loss.backward()
        optimizer.step()
        if batch_idx % log_interval == 0:
            print('Train Epoch: {} [{}/{} ({:.0f}%)]\tLoss: {:.6f}'.format(
                epoch, batch_idx * len(data), len(train_loader.dataset),
                100. * batch_idx / len(train_loader), loss.item()))

def test(log_interval, model, device, test_loader):
    model.eval()
    test_loss = 0
    correct = 0
    with torch.no_grad():
        for data, target in test_loader:
            data, target = data.to(device), target.to(device)
            output = model(data)
            test_loss += F.nll_loss(output, target, reduction='sum').item()
            pred = output.argmax(dim=1, keepdim=True)
            correct += pred.eq(target.view_as(pred)).sum().item()

    test_loss /= len(test_loader.dataset)

    print('\nTest set: Average loss: {:.4f}, Accuracy: {}/{} ({:.0f}%)\n'.format
          (test_loss, correct, len(test_loader.dataset),
        100. * correct / len(test_loader.dataset)))


# Train and Test the model and save it.
for epoch in range(1, 11):
    train(log_interval, model, device, train_loader, optimizer, epoch)
    test(log_interval, model, device, test_loader)
torch.save(model, './model.pt')

 

최종 결과

init model done
set vars and device done
Train Epoch: 1 [0/60000 (0%)]	Loss: 2.319003
Train Epoch: 1 [12800/60000 (21%)]	Loss: 2.308317
Train Epoch: 1 [25600/60000 (43%)]	Loss: 2.259772
Train Epoch: 1 [38400/60000 (64%)]	Loss: 2.114968
Train Epoch: 1 [51200/60000 (85%)]	Loss: 1.092506

Test set: Average loss: 0.7195, Accuracy: 7655/10000 (77%)

Train Epoch: 2 [0/60000 (0%)]	Loss: 0.710096
Train Epoch: 2 [12800/60000 (21%)]	Loss: 0.628659
Train Epoch: 2 [25600/60000 (43%)]	Loss: 0.429823
Train Epoch: 2 [38400/60000 (64%)]	Loss: 0.444784
Train Epoch: 2 [51200/60000 (85%)]	Loss: 0.320472

Test set: Average loss: 0.3158, Accuracy: 9107/10000 (91%)

Train Epoch: 3 [0/60000 (0%)]	Loss: 0.226330
Train Epoch: 3 [12800/60000 (21%)]	Loss: 0.206977
Train Epoch: 3 [25600/60000 (43%)]	Loss: 0.111615
Train Epoch: 3 [38400/60000 (64%)]	Loss: 0.287350
Train Epoch: 3 [51200/60000 (85%)]	Loss: 0.149734

Test set: Average loss: 0.2045, Accuracy: 9436/10000 (94%)

Train Epoch: 4 [0/60000 (0%)]	Loss: 0.096651
Train Epoch: 4 [12800/60000 (21%)]	Loss: 0.152811
Train Epoch: 4 [25600/60000 (43%)]	Loss: 0.121838
Train Epoch: 4 [38400/60000 (64%)]	Loss: 0.128148
Train Epoch: 4 [51200/60000 (85%)]	Loss: 0.209051

Test set: Average loss: 0.1371, Accuracy: 9585/10000 (96%)

Train Epoch: 5 [0/60000 (0%)]	Loss: 0.123022
Train Epoch: 5 [12800/60000 (21%)]	Loss: 0.047610
Train Epoch: 5 [25600/60000 (43%)]	Loss: 0.025467
Train Epoch: 5 [38400/60000 (64%)]	Loss: 0.047583
Train Epoch: 5 [51200/60000 (85%)]	Loss: 0.054973

Test set: Average loss: 0.1139, Accuracy: 9663/10000 (97%)

Train Epoch: 6 [0/60000 (0%)]	Loss: 0.065705
Train Epoch: 6 [12800/60000 (21%)]	Loss: 0.029514
Train Epoch: 6 [25600/60000 (43%)]	Loss: 0.029115
Train Epoch: 6 [38400/60000 (64%)]	Loss: 0.048393
Train Epoch: 6 [51200/60000 (85%)]	Loss: 0.101836

Test set: Average loss: 0.1020, Accuracy: 9697/10000 (97%)

Train Epoch: 7 [0/60000 (0%)]	Loss: 0.011763
Train Epoch: 7 [12800/60000 (21%)]	Loss: 0.026959
Train Epoch: 7 [25600/60000 (43%)]	Loss: 0.093610
Train Epoch: 7 [38400/60000 (64%)]	Loss: 0.022231
Train Epoch: 7 [51200/60000 (85%)]	Loss: 0.013581

Test set: Average loss: 0.1001, Accuracy: 9699/10000 (97%)

Train Epoch: 8 [0/60000 (0%)]	Loss: 0.034948
Train Epoch: 8 [12800/60000 (21%)]	Loss: 0.077487
Train Epoch: 8 [25600/60000 (43%)]	Loss: 0.025672
Train Epoch: 8 [38400/60000 (64%)]	Loss: 0.022483
Train Epoch: 8 [51200/60000 (85%)]	Loss: 0.016120

Test set: Average loss: 0.1090, Accuracy: 9687/10000 (97%)

Train Epoch: 9 [0/60000 (0%)]	Loss: 0.053953
Train Epoch: 9 [12800/60000 (21%)]	Loss: 0.016929
Train Epoch: 9 [25600/60000 (43%)]	Loss: 0.067918
Train Epoch: 9 [38400/60000 (64%)]	Loss: 0.026225
Train Epoch: 9 [51200/60000 (85%)]	Loss: 0.009774

Test set: Average loss: 0.0981, Accuracy: 9720/10000 (97%)

Train Epoch: 10 [0/60000 (0%)]	Loss: 0.056655
Train Epoch: 10 [12800/60000 (21%)]	Loss: 0.033188
Train Epoch: 10 [25600/60000 (43%)]	Loss: 0.020561
Train Epoch: 10 [38400/60000 (64%)]	Loss: 0.003139
Train Epoch: 10 [51200/60000 (85%)]	Loss: 0.007730

Test set: Average loss: 0.0914, Accuracy: 9758/10000 (98%)


Process finished with exit code 0

 

CNN 모델 사용하기 (additional)

class Net(nn.Module):
    def __init__(self):
        super(Net, self).__init__()
        self.conv1 = nn.Conv2d(1, 32, 3, 1)
        self.conv2 = nn.Conv2d(32, 64, 3, 1)
        self.dropout1 = nn.Dropout2d(0.25)
        self.dropout2 = nn.Dropout2d(0.5)
        self.fc1 = nn.Linear(9216, 128)
        self.fc2 = nn.Linear(128, 10)

    def forward(self, x):
        x = self.conv1(x)
        x = F.relu(x)
        x = self.conv2(x)
        x = F.relu(x)
        x = F.max_pool2d(x, 2)
        x = self.dropout1(x)
        x = torch.flatten(x, 1)
        x = self.fc1(x)
        x = F.relu(x)
        x = self.dropout2(x)
        x = self.fc2(x)
        output = F.log_softmax(x, dim=1)
        return output

 

출처 : https://korchris.github.io/2019/08/23/mnist/

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