I ref this 86 code which directly convert input from FloatTensor to Variable, not from CudaFloatTensor. So should I write code like this:
for i, (input, target) in enumerate(test_loader):
        with torch.cuda.device(0):
	        target = target.cuda(async=True) # in test loader, pin_memory = True
	        input = input.cuda(async=True)

        target_var = torch.autograd.Variable(target, volatile=False)
        input_var = torch.autograd.Variable(input, volatile=False)