healpix_analyse.LocalizedFlatSkyAlm

LocalizedFlatSkyAlm.py

Modified from LocalizedAlm_optimized_v13_fixed.py. - Removed exact Y_lm (Legendre Polynomial) precomputation to solve RAM explosion at high N_side. - Implements Phase-Aligned Flat-Sky Approximation using a 2D FFT (1D Longitude + 1D Latitude). - Isotropically bins the 2D Cartesian power spectrum into 1D multipoles (ell).

Classes

LocalizedFlatSkyAlm

Localized spherical harmonic analysis using a Phase-Aligned Flat-Sky FFT.

Module Contents

class healpix_analyse.LocalizedFlatSkyAlm.LocalizedFlatSkyAlm(level, patch_idx_ring, backend, lmax=None, lmax_compute=None)

Bases: foscat.alm.alm

Localized spherical harmonic analysis using a Phase-Aligned Flat-Sky FFT. Avoids O(lmax^2) memory bottlenecks for ultra-high resolution maps.

level

nside

patch_idx_ring

device

dtype

lmax_full

lmax_compute

active_shift_ph

comp_tf_localized(u_patch)

Compute 1D Longitude FFT on active rings & apply phase alignment.

anafast_localized(u_patch, map2_patch=None, bandpowers_binning=None)

Compute pseudo-Cl using a 2D Phase-Aligned Flat-Sky FFT.