How to convert Pytorch autograd.Variable to Numpy?

Question

The title says it all. I want to convert a PyTorch autograd.Variable to its equivalent numpy array. In their official documentation they advocated

Answer 1

Two possible case

• Using GPU: If you try to convert a cuda float-tensor directly to numpy like shown below,it will throw an error.

  x.data.numpy()

  RuntimeError: numpy conversion for FloatTensor is not supported

  So, you cant covert a cuda float-tensor directly to numpy, instead you have to convert it into a cpu float-tensor first, and try converting into numpy, like shown below.

  x.data.cpu().numpy()

• Using CPU: Converting a CPU tensor is straight forward.

  x.data.numpy()

Answer 2

I have found the way. Actually, I can first extract the Tensor data from the autograd.Variable by using a.data. Then the rest part is really simple. I just use a.data.numpy() to get the equivalent numpy array. Here's the steps:

a = a.data  # a is now torch.Tensor
a = a.numpy()  # a is now numpy array