BBPower - the C_ell-based pipeline for BB

This repo hosts a pipeline that carries out a maps-to-params analysis of multi-frequency polarization data to constrain primordial B-modes using a power-spectrum-based component separation scheme. The pipeline is built following the BBPipe framework. BBPipe is a pipeline constructor used to connect different pipeline stages in terms of their outputs and required inputs, and it's one of BBPower's dependencies.

Dependencies

You should install the following non-standard python packages in order to use BBPower:

• BBPipe
• sacc
• fgbuster
• emcee

Using the code

First of all, have a look at the BBPipe documentation to get a broad idea of how the pipeline structure works. Then, have a look at one of the test suites in the test directory. For instance, a quick pipeline that takes calculated power spectra, runs an MCMC on them and creates a bunch of plots, is contained in the following files:

• test/test_sampling.yml describes the raw inputs of the pipeline (in this case, multi-frequency power spectra) and its stages (in this case, two stages, a likelihood sampling stage and a plotting stage).
• test/test_config_sampling.yml describes the configuration options for the different stages. This includes, for instance, the cosmological and foreground model, parameter priors, sampler options etc. All the possible options are thoroughly described there.
• test/run_sampling_test.sh contains the commands that would be needed to run this pipeline. The commands of the form python -m bbpower ... are output by BBPipe if you just run bbpipe ./test/test_sampling.yml --dry-run.

Credits and questions

Get in touch with Max Abitbol (mabitbol), David Alonso (damonge) or anyone else in the SO BB AWG if you have questions or queries about the code.