update samples from Release-66 as a part of SDK release

how-to-use-azureml/ml-frameworks/using-mlflow/train-and-deploy-pytorch/scripts/train.py

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+# Copyright (c) 2017, PyTorch Team
+# All rights reserved
+# Licensed under BSD 3-Clause License.
+
+# This example is based on PyTorch MNIST example:
+# https://github.com/pytorch/examples/blob/master/mnist/main.py
+
+import mlflow
+import mlflow.pytorch
+from mlflow.utils.environment import _mlflow_conda_env
+import warnings
+import cloudpickle
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+import torch.optim as optim
+import torchvision
+from torchvision import datasets, transforms
+
+
+class Net(nn.Module):
+    def __init__(self):
+        super(Net, 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):
+        # Added the view for reshaping score requests
+        x = x.view(-1, 1, 28, 28)
+        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 F.log_softmax(x, dim=1)
+
+
+def train(args, 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 % args.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()))
+            # Use MLflow logging
+            mlflow.log_metric("epoch_loss", loss.item())
+
+
+def test(args, 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)
+            # sum up batch loss
+            test_loss += F.nll_loss(output, target, reduction="sum").item()
+            # get the index of the max log-probability
+            pred = output.argmax(dim=1, keepdim=True)
+            correct += pred.eq(target.view_as(pred)).sum().item()
+
+    test_loss /= len(test_loader.dataset)
+    print("\n")
+    print("Test set: Average loss: {:.4f}, Accuracy: {}/{} ({:.0f}%)\n".format(
+        test_loss, correct, len(test_loader.dataset),
+        100. * correct / len(test_loader.dataset)))
+    # Use MLflow logging
+    mlflow.log_metric("average_loss", test_loss)
+
+
+class Args(object):
+    pass
+
+
+# Training settings
+args = Args()
+setattr(args, 'batch_size', 64)
+setattr(args, 'test_batch_size', 1000)
+setattr(args, 'epochs', 3)  # Higher number for better convergence
+setattr(args, 'lr', 0.01)
+setattr(args, 'momentum', 0.5)
+setattr(args, 'no_cuda', True)
+setattr(args, 'seed', 1)
+setattr(args, 'log_interval', 10)
+setattr(args, 'save_model', True)
+
+use_cuda = not args.no_cuda and torch.cuda.is_available()
+
+torch.manual_seed(args.seed)
+
+device = torch.device("cuda" if use_cuda else "cpu")
+
+kwargs = {'num_workers': 1, 'pin_memory': True} if use_cuda else {}
+train_loader = torch.utils.data.DataLoader(
+    datasets.MNIST('../data', train=True, download=True,
+                   transform=transforms.Compose([
+                       transforms.ToTensor(),
+                       transforms.Normalize((0.1307,), (0.3081,))
+                   ])),
+    batch_size=args.batch_size, shuffle=True, **kwargs)
+test_loader = torch.utils.data.DataLoader(
+    datasets.MNIST(
+        '../data',
+        train=False,
+        transform=transforms.Compose([
+            transforms.ToTensor(),
+            transforms.Normalize((0.1307,), (0.3081,))])),
+    batch_size=args.test_batch_size, shuffle=True, **kwargs)
+
+
+def driver():
+    warnings.filterwarnings("ignore")
+    # Dependencies for deploying the model
+    pytorch_index = "https://download.pytorch.org/whl/"
+    pytorch_version = "cpu/torch-1.1.0-cp36-cp36m-linux_x86_64.whl"
+    deps = [
+        "cloudpickle=={}".format(cloudpickle.__version__),
+        pytorch_index + pytorch_version,
+        "torchvision=={}".format(torchvision.__version__),
+        "Pillow=={}".format("6.0.0")
+    ]
+    with mlflow.start_run() as run:
+        model = Net().to(device)
+        optimizer = optim.SGD(
+            model.parameters(),
+            lr=args.lr,
+            momentum=args.momentum)
+        for epoch in range(1, args.epochs + 1):
+            train(args, model, device, train_loader, optimizer, epoch)
+            test(args, model, device, test_loader)
+        # Log model to run history using MLflow
+        if args.save_model:
+            model_env = _mlflow_conda_env(additional_pip_deps=deps)
+            mlflow.pytorch.log_model(model, "model", conda_env=model_env)
+    return run
+
+
+if __name__ == "__main__":
+    driver()