test can't run in 0.1.8

[CaiWang0503]

hi there,
when i update to 0.1.8 and run the test model, it throws an error.
what happen with my mac?

[MaximilianPi]

Hi Cai Wang,
the package is not yet compatible with torch 1.9 (which was published this week), I will fix this asap.

[MaximilianPi]

I pushed a fix. The problem was that the tensordot function didn't has the same signature for torch and torchscript in the past (an additional jit compilation step we use), see https://pytorch.org/docs/stable/jit_unsupported.html. PyTorch 1.9 seems to fix this behaviour but it would break compatibility with older versions. But I was able to solve this issue by using einsum instead of tensordot.