Tutorials#

This section contains a series of tutorial notebooks which go through some of the key features of the S2FFT package.

At a high-level the S2FFT package is structured such that the two primary transforms, the Wigner and spherical harmonic transforms, can easily be accessed.

Core usage 🚀#

To import and use S2FFT is as simple follows:

For a signal on the sphere

import s2fft

# Specify sampled signal and harmonic bandlimit
f = ...
L = ...

# Compute harmonic coefficients
flm = s2fft.forward(f, L, method="jax")

# Map back to pixel-space signal
f = s2fft.inverse(flm, L, method="jax")

For a signal on the rotation group

import s2fft

# Define sampled signal, harmonic & azimuthal bandlimits
f = ...
L, N = ...

# Compute Wigner coefficients
flmn = s2fft.wigner.forward(f, L, N, method="jax")

# Map back to pixel-space signal
f = s2fft.wigner.inverse(flmn, L, N, method="jax")

Tutorial notebooks#

Below are a few short tutorials that cover how to use specific features of S2FFT.

We also have a notebook demonstrating how to use CUDA-accelerated HEALPix spherical harmonic transforms in S2FFT, which is accessible in notebook format here, or alternatively can be opened in Google Colab.