Command line flags for cosmosis-extract

The cosmosis-extract tool extracts the original parameter files that were used to generate a CosmoSIS chain from the chain output file.

You can view command line flags for cosmosis-extract using the command:

cosmosis-extract --help

Purpose

When CosmoSIS runs, it saves copies of the parameter files used (params.ini, values.ini, priors.ini) in the header of the output chain file as comments. The cosmosis-extract tool reads these embedded files and saves them as separate .ini files.

This is useful for:

  • Reproducing previous results

  • Understanding exactly what parameters were used for a particular run

  • Debugging parameter settings

  • Creating starting points for new analyses

Usage

Extract parameter files from a chain:

cosmosis-extract chain_file.txt output_prefix

This will create three files:

  • output_prefix_params.ini - The main parameter file

  • output_prefix_values.ini - The values/ranges file

  • output_prefix_priors.ini - The priors file

Arguments

  • chain: Name of the chain file to read from

  • prefix: Prefix for the output files that will be created

Example

cosmosis-extract output/demo1.txt recovered_demo1

This will create:

  • recovered_demo1_params.ini

  • recovered_demo1_values.ini

  • recovered_demo1_priors.ini

You can then use these files to re-run the same analysis:

cosmosis recovered_demo1_params.ini