PyTorch for WebGPU

Oddly, two tests fail for me with Brave (Version 1.51.118 / Chromium: 113.0.5672.126 (arm64)) on macOS Ventura 13.3.1

- pow([0], [0]) gradient, with "Expected «-Infinity» to be close to «0» (diff: < 0.0000005)"

- xlogy([0], [0.30000001192092896]) gradient with "Expected «0» to be close to «-1.2039728164672852»"

>>activa+S4
Yeah so the thing is WebGPU doesn’t correctly support IEEE floating point. Particularly, 0 is often substituted for +-Inf and NaN. See section 14.6 of the spec.

https://www.w3.org/TR/WGSL/#floating-point-evaluation

It’s not such a problem for real nets since you avoid those values like the plague. But the tests catch them and I need to make the tests are tolerant. Thanks for the results!

zlacker