VatsalyaSharan / aps_namaster

This code computes the angular power spectrum of a galaxy catalog using NaMaster library.

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Description

The present pipeline computes the angular power spectrum (APS) of a masked scalar field, that is usually a galaxy catalog with limited survey area, using NaMaster library (https://github.com/LSSTDESC/NaMaster) developed by David Alonso, Javier Sanchez and Anže Slosar for the LSST Dark Energy Science Collaboration.

In general description, NaMaster is a C library, Python module and standalone program to compute full-sky angular cross-power spectra of masked, spin-0 and spin-2 fields with an arbitrary number of known contaminants using a pseudo-Cl (aka MASTER) approach. The code also implements E/B-mode purification and is available in both full-sky and flat-sky modes. Details about this approach can be found in: https://arxiv.org/abs/1809.09603.

The present pipeline runs with the Python module of NaMaster, the pymaster (https://namaster.readthedocs.io/en/latest/index.html). It has already been optimized to compute APS of many galaxy catalogs simultaneously using parallelization method of mpi4py. One direct application of measures pipeline is to calculate covariance matrix on a sample mock catalogs for cosmological analysis.

Instructions for use:

1 - setup repository_name global variable for your directory; 2 - in this directory, there should be two subdirectories: one called 'mock_cats' where are catalogs and another 'outputs' where outputs files will be salved; 3 - in 'outputs' directory there should be a directory called 'cldata' where all the cl measurements will be salved. 4 - in your repository there should be a binning cl file 'bin.dat' following the namaster configuration

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This code computes the angular power spectrum of a galaxy catalog using NaMaster library.


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