Friday, April 30, 2010

Version 1.0 beta is now public!

You can download the code here (please see new version).

Feedback will be greatly appreciated.
Please leave your email here if you would like to receive information about further upgrades.

SimFast21 v1.0 beta

Copyright 2010 Mario Santos, Luis Ferramacho, Marta Silva, Alexandre Amblard, Asantha Cooray

This program is distributed under the terms of the GNU General Public License (

Contact: mgrsantos at


This program generates a simulation of the cosmological 21cm signal (see paper for details).
To run just do: ./simfast21 base_dir where “base_dir” is the base directory where you want your simulation to reside (note that the files can be quite big). This base directory must contain the parameters file simfast21.ini (see the copy that comes with the distribution for further details on how to use this file).

The program will create the following directory structure:

  • base_dir
    • /density - contains the matter density (delta) box for z=0 and nonlinear boxes for all redshifts
    • /Velocity - Velocity at z=0
    • /Halos - halo catalogs and nonlinear collapsed mass boxes
    • /Ionization - ionization fraction boxes
    • /SFR - Star formation rate density boxes
    • /xrays - boxes to calculate heating due to xrays
    • /Lya - Lya coupling
    • /xc - collisional coupling
    • /deltaTb - final 21cm brightness temperature boxes
    • /Output_text_files - Several text files generated during the simulation (averages, etc)

The output boxes are binary files with N^3 elements where each element is a float (usually 4 bytes) and N^3 is the total number of cells in the box.


Just run make.
It requires the Gnu Scientific Library and the FFTW libraries.