*** Computing "non-linear mass," Mstar (in units of h^-1 Msun) ***
June 22, 2011

Here we provide a simple program, compute_mstar.f90, for computing 
the so-called "non-linear mass," usually denoted as "Mstar," which 
is defined as a solution of 

   sigma(Mstar,z)=1.6865

where sigma(M,z) is the r.m.s. mass fluctuation at a given redshift z. 
The above equation is solved by a non-linear equation solver "zbrent"
of Numerical Recipes. 

- To compile and use the program, edit Makefile and simply "make"
- It will generate executable called "compute_mstar"
- Running "compute_mstar" will ask you to enter the redshift at which Mstar is evaluated

To compute sigma(M), it is necessary to use the input linear power spectrum.
We provide the sample data, "wmap5baosn_max_likelihood_matterpower.dat,"
which was generated using CAMB code for the maximum likelihood parameters
given in Table I of Komatsu et al.(2008) [WMAP 5-year interpretation paper] 
with "WMAP5+BAO+SN". The input file for CAMB is also provided 
(wmap5baosn_max_likelihood_params.ini). NOTE THAT THIS POWER SPECTRUM IS 
COMPUTED AT Z=0.

However, it is more convenient to use the power spectrum evolved back to z=30, 
which is known quite accurately, and extrapolate it to low redshifts using the 
growth factor, which depends on more uncertain things like the equation of state
of dark energy. Therefore, the code uses the power spectrum at z=30 and extrapolates
to a redshift of your choice. The data are provided as 
"wmap5baosn_max_likelihood_matterpower_at_z=30.dat", whose format is

1st column: wavenumber in units of h Mpc^-1
2nd column: power spectrum in units of h^-3 Mpc^3