[solved] wrong MNIST format

[Alchemist77]

error:
RuntimeError: output with shape [1, 28, 28] doesn't match the broadcast shape [3, 28, 28]

MNIST has [1, 28, 28] and [3. 28. 28] two format. In this code,
change
transforms.Normalize(mean=(0.5, 0.5, 0.5), std=(0.5, 0.5, 0.5))
to
transforms.Normalize([0.5], [0.5])