Port to Metal Shaders

[36000]

It would potentially be useful to write a version of this for personal mac laptops. This would be for convenience for researchers. The Metal Shading Language (MSL) is similar to CUDA C, but the architecture is very different. Really only probabilistic (not PTT or bootstrap) would need to be ported.

[skoudoro]

Concerning this topic, I started to look at wgpu and its compute shader.
Wgpu is a layer above metal, Vulcan and directx and it can be a multiplatform way to use gpu.

Anyway, I will provide feedback and performance when I have an update on this