First implementation of lyaps

23 June 2025

Removing P1D from picca

Corentin Ravoux                                                                                                                                                              Lyman-alpha soft TG - 23 June

Removing P1D from picca

Corentin Ravoux                                                                                                                                                              Lyman-alpha soft TG - 23 June

• Only for P1D FFT
• Not very modular
• Hard to optimize/vectorize (e.g. to port to GPU with Jax)
• Very hard to read/contribute

Removing P1D from picca

Corentin Ravoux                                                                                                                                                              Lyman-alpha soft TG - 23 June

• Separate package for most of power spectrum applications: P1D, cross-exposure, zero padding, Pcross, B1D
• Common routines for FFT
• Separated subpackages for each applications: fft1d, fftcross...
• Dedicated & optimized IO
• Potential introduction of JAX
• QMLE not planed

First steps

Corentin Ravoux                                                                                                                                                              Lyman-alpha soft TG - 23 June

• IO tests
• Getting and writting full delta information.
• Treating masking for the zero padding
• Deals with general wavelength weighting or wavenumber (k) weighting

First steps: zero padding and splitting

Corentin Ravoux                                                                                                                                                              Lyman-alpha soft TG - 23 June

Delta splitting (both irregular and regular wavelength grids)

Zero padding implemented, proper weight treatment

First steps: fourier

Corentin Ravoux                                                                                                                                                              Lyman-alpha soft TG - 23 June

• FFT of deltas in any configurations
• Treatment of resolution & noise (speed improved with white noise assumption)
• Saving: depends on the need of each analysis
• Two format (regular and irregular wavenumber grid)

Next steps

Corentin Ravoux                                                                                                                                                              Lyman-alpha soft TG - 23 June

• Config file for the common part (IO, delta treatment & FFT)
• IO and FFT optimizations
• Work on the subpackages: start with fft1d to compare to Y1 with picca.pk1d
• Any suggestion or feature needed ?