Torch Root finding

[ravioli1369]

Use torch for most scipy/healpy functions

This version is much slower (~10 times) than the scipy/healpy equivalent.

[deepchatterjeeligo]

A few thoughts.

• Let's make the auxiliary functions compatible with both numpy and torch depending on the input. This will ensure that the current features are maintained.
• Define a new module (maybe solver.py) for the torch newton solver which will import the functions from above.
• And another .py file called healpix_utils.py that contain the torch based healpux functions.
• Add some testing for the core solver using simple polynomials or anything else you see fit. If you can add a test for the ansatz using the auxiliary functions in addition its even better.

[ravioli1369]

ML4GW/ml4gw#193 should be merged before this

[EthanMarx]

If this is 10 times slower, why are we merging it in?

[deepchatterjeeligo]

If this is 10 times slower, why are we merging it in?

I want to keep the feature, though not use it rightaway until the issue with the speed is resolved. My hope is that we will be able to improve on the speed once someone can take a closer look.

[EthanMarx]

Okay thats makes sense. I suggest we keep it as a draft PR then until someone has the chance to take a look.