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an example of pytorch on mnist dataset
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| import os | |
| import torch | |
| import torch.nn as nn | |
| from torch.autograd import Variable | |
| import torchvision.datasets as dset | |
| import torchvision.transforms as transforms | |
| import torch.nn.functional as F | |
| import torch.optim as optim | |
| ## load mnist dataset | |
| use_cuda = torch.cuda.is_available() | |
| root = './data' | |
| if not os.path.exists(root): | |
| os.mkdir(root) | |
| trans = transforms.Compose([transforms.ToTensor(), transforms.Normalize((0.5,), (1.0,))]) | |
| # if not exist, download mnist dataset | |
| train_set = dset.MNIST(root=root, train=True, transform=trans, download=True) | |
| test_set = dset.MNIST(root=root, train=False, transform=trans, download=True) | |
| batch_size = 100 | |
| train_loader = torch.utils.data.DataLoader( | |
| dataset=train_set, | |
| batch_size=batch_size, | |
| shuffle=True) | |
| test_loader = torch.utils.data.DataLoader( | |
| dataset=test_set, | |
| batch_size=batch_size, | |
| shuffle=False) | |
| print '==>>> total trainning batch number: {}'.format(len(train_loader)) | |
| print '==>>> total testing batch number: {}'.format(len(test_loader)) | |
| ## network | |
| class MLPNet(nn.Module): | |
| def __init__(self): | |
| super(MLPNet, self).__init__() | |
| self.fc1 = nn.Linear(28*28, 500) | |
| self.fc2 = nn.Linear(500, 256) | |
| self.fc3 = nn.Linear(256, 10) | |
| def forward(self, x): | |
| x = x.view(-1, 28*28) | |
| x = F.relu(self.fc1(x)) | |
| x = F.relu(self.fc2(x)) | |
| x = self.fc3(x) | |
| return x | |
| def name(self): | |
| return "MLP" | |
| class LeNet(nn.Module): | |
| def __init__(self): | |
| super(LeNet, self).__init__() | |
| self.conv1 = nn.Conv2d(1, 20, 5, 1) | |
| self.conv2 = nn.Conv2d(20, 50, 5, 1) | |
| self.fc1 = nn.Linear(4*4*50, 500) | |
| self.fc2 = nn.Linear(500, 10) | |
| def forward(self, x): | |
| x = F.relu(self.conv1(x)) | |
| x = F.max_pool2d(x, 2, 2) | |
| x = F.relu(self.conv2(x)) | |
| x = F.max_pool2d(x, 2, 2) | |
| x = x.view(-1, 4*4*50) | |
| x = F.relu(self.fc1(x)) | |
| x = self.fc2(x) | |
| return x | |
| def name(self): | |
| return "LeNet" | |
| ## training | |
| model = LeNet() | |
| if use_cuda: | |
| model = model.cuda() | |
| optimizer = optim.SGD(model.parameters(), lr=0.01, momentum=0.9) | |
| criterion = nn.CrossEntropyLoss() | |
| for epoch in xrange(10): | |
| # trainning | |
| ave_loss = 0 | |
| for batch_idx, (x, target) in enumerate(train_loader): | |
| optimizer.zero_grad() | |
| if use_cuda: | |
| x, target = x.cuda(), target.cuda() | |
| x, target = Variable(x), Variable(target) | |
| out = model(x) | |
| loss = criterion(out, target) | |
| ave_loss = ave_loss * 0.9 + loss.data[0] * 0.1 | |
| loss.backward() | |
| optimizer.step() | |
| if (batch_idx+1) % 100 == 0 or (batch_idx+1) == len(train_loader): | |
| print '==>>> epoch: {}, batch index: {}, train loss: {:.6f}'.format( | |
| epoch, batch_idx+1, ave_loss) | |
| # testing | |
| correct_cnt, ave_loss = 0, 0 | |
| total_cnt = 0 | |
| for batch_idx, (x, target) in enumerate(test_loader): | |
| if use_cuda: | |
| x, target = x.cuda(), target.cuda() | |
| x, target = Variable(x, volatile=True), Variable(target, volatile=True) | |
| out = model(x) | |
| loss = criterion(out, target) | |
| _, pred_label = torch.max(out.data, 1) | |
| total_cnt += x.data.size()[0] | |
| correct_cnt += (pred_label == target.data).sum() | |
| # smooth average | |
| ave_loss = ave_loss * 0.9 + loss.data[0] * 0.1 | |
| if(batch_idx+1) % 100 == 0 or (batch_idx+1) == len(test_loader): | |
| print '==>>> epoch: {}, batch index: {}, test loss: {:.6f}, acc: {:.3f}'.format( | |
| epoch, batch_idx+1, ave_loss, correct_cnt * 1.0 / total_cnt) | |
| torch.save(model.state_dict(), model.name()) | |
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