This minor release of S2FFT aims to increase the accessibility of differentiable harmonic transforms to users without easy access to GPU compute resources. We provide custom JAX frontends for existing CPU bound C/C++ spherical harmonic libraries, at this point we capture the functionality of SSHT and HEALPix though in principle any spherical harmonics could easily be integrated.
Tip
For details on this approach see the original derivation in section 5.3.1 and 5.3.2 of Price & McEwen 2023.
Main changelog:
- JAX frontend support for HEALPix C++ library
- JAX frontend support for SSHT C library
- Reverse mode gradients for above validated against finite difference