How to convert Pytorch autograd.Variable to Numpy?

numpy pytorch tensor
Bishwajit Purkaystha picture Bishwajit Purkaystha · Jun 3, 2017 · Viewed 16.6k times · Source

The title says it all. I want to convert a PyTorch autograd.Variable to its equivalent numpy array. In their official documentation they advocated using a.numpy() to get the equivalent numpy array (for PyTorch tensor). But this gives me the following error:

Traceback (most recent call last): File "stdin", line 1, in module File "/home/bishwajit/anaconda3/lib/python3.6/site-packages/torch/autograd/variable.py", line 63, in getattr raise AttributeError(name) AttributeError: numpy

Is there any way I can circumvent this?

Answer

blitu12345 picture blitu12345 · Jun 4, 2017

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()

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