rotations

s2fft.utils.rotation.generate_rotate_dls(L: int, beta: float) → Array

Function which recursively generates the complete plane of reduced

Wigner d-function coefficients at a given rotation beta.

Parameters:

• L (int) – Harmonic band-limit.

• beta (float) – Rotation on the sphere.

Returns:

Complete array of [L, 2L-1,2L-1] Wigner d-function coefficients

for a fixed rotation beta.

Return type:

jnp.ndarray

s2fft.utils.rotation.rotate_flms(flm: Array, L: int, rotation: Tuple[float, float, float], dl_array: Array = None) → Array

Rotates an array of spherical harmonic coefficients by angle rotation.

Parameters:

• flm (jnp.ndarray) – Array of spherical harmonic coefficients.

• L (int) – Harmonic band-limit.

• rotation (Tuple[float, float, float]) – Rotation on the sphere (alpha, beta, gamma).

• dl_array (jnp.ndarray, optional) – Precomputed array of reduced Wigner d-function coefficients, see :func:~`generate_rotate_dls`. Defaults to None.

Returns:

Rotated spherical harmonic coefficients with shape [L,2L-1].

Return type:

jnp.ndarray