fix(examples) Fix quickstart-pytorch GPU RuntimeError (#4386)

examples/quickstart-pytorch/pytorchexample/task.py

@@ -100,6 +100,7 @@ def train(net, trainloader, valloader, epochs, learning_rate, device):
 
 def test(net, testloader, device):
     """Validate the model on the test set."""
+    net.to(device)  # move model to GPU if available
     criterion = torch.nn.CrossEntropyLoss()
     correct, loss = 0, 0.0
     with torch.no_grad():