EXCOP v0.1

Density of Matter vs. Dark Energy likelihood contour

Download EXCOP.tar

The EXctration of COsomogical Pararmeters software (EXCOP) is a set of C and IDL programs together with a very large database of cosmological models generated by CMBFAST that will compute likelihood functions for cosmological parameters given some CMB data. This is the software and database used in the Stompor et al. (2001) analysis of the high resoultion Maxima1 CMB anisotropy map described in Lee et al. (2001). It was developed by Matthew Abroe at the University of Minnesota Supercomputing Institute, under the auspicies of the COMBAT collaboration.

Once you have downloaded EXCOP.tar type:

tar xvfm EXCOP.tar

EXCOP is comprised of three directories:

Code/
Data/
Database/

The Code directory

To compile the C programs go to the Code directory and simply type 'make'. You will then have three exectables:

read*
chi2*
like*

Use read* to output a model from the database. Enter the parameter indicies of the desired model, and read* will output the angular power spectrum of temperature fluctuations for that particular model to the Code/models directory. The file name will be model-p1-p2-p3-p4-p5-p6 where p1-p6 are the values of the cosmological parameters for that model. The file will contain two columns. The first column has the spherical harmonic multipole values, and the second has the corresponding

in units of

. Note that this database contains the power spectra for temperature fluctations only; no polarization power spectra.

Use chi2* to compute the offset log-normal chi2 described in Bond, Jaffe, & Knox (1998) of your CMB data (contained in a specific format described below) with a desired model from the database. Again, first enter the parameter indicies of the desired model, and then enter how you would like solve for the calibration parameters for each experiment. The first (and recommended) method numerically minimizes the chi2 with respect to the calibartion parameter for each experment and the COBE normalization. The second method COBE normalizes, and assumes the rest of the calibration parameters are unity. The third method prompts the user to manually input the calibration parameters.

like* will compute the chi2 for every model in the database. To run type:

like* taui tol

where taui is the index for the tau paraeter in the database, and thus must be an integer between 0 and 8 inclusive. like* uses a numberical minization to solve for the calibration paraemters (option 0 in chi2*) tol It outputs a multi-dimensional binary file called Code/LIKELIHOOD . This is used as the input to the IDL programs.

The Data directory

The Data/ directory contains the experimental CMB data. EXCOP is explicity designed to include data from multiple experiments. The number of experiments is stored in the variable NEXP, defined in Code/excop.h. The experimental variables defined at the top of the file Code/func.c They are:

NBAND : integer array of length NEXP, number of band powers for each experiment
LMAX : integer array of length NEXP, maximum sperical harmonic multiple detected for each experiment
SIG : float arry of lenth NEXP, calibration uncertainty in power for each experiment

In the Data/ directory there are NEXP subdirectories written as Data/expi/, where i is the experiment index. In each Data/expi/ subdirectory are three files:

cls
cov
window

The cls file contains two colums of length NBAND. The first column has the

band powers in units of

, followed by the xb value for that band, described in equation 69 of Bond, Jaffe, & Knox (1998).

The cov contains the covariance (inverse fisher) matrix for the band powers. It should contain NBAND * NBAND elements.

The window file contains the window function for each band power. There are NBAND +1 columns of length LMAX -1. The first column contains the spherical harmonic multipole index, starting as 2 and ending at LMAX. The proceeding columns contain the window function for each band power in order.

The Database directory

The cosmological parameters and associated values in the database are described here.

You really have no need to ever go into this directory, but we describe the storage method nonetheless. In this directory are subdirectories called Database/model-i1-i2/ where i1 and i2 are the indicies for the first and second cosmological parameter, respectively. Within each subdirectory are files named Database/model-i1-i2/model-p1-p2-p3-p4-p5', where p1-p5 are the values of the first five cosmological parameters.