Counts of Amplified Mass Elevations from Lensing with Ultrafast Simulation
Chieh-An Lin (CEA Saclay)
Release v1.2 - 2015-04-06
Camelus is a fast weak-lensing peak-count modeling algorithm in C. It provides a prediction on peak counts from input cosmological parameters.
Here is the summary of the algorithm:
- Sample halos from a mass function
- Assign density profiles, randomize their positions
- Compute the projected mass, add noise
- Make maps and create peak catalogues
For a more detailed description, please take a look at Lin & Kilbinger (2015a).
The following softwares are required:
- cmake
- gcc
- gsl
- fftw
- nicaea v2.5
For Mac users, do the follows before compilation:
$ export CC=gcc
$ export CXX=g++
or use setenv command in tcsh.
To compile the package:
$ export NICAEA={PATH_OF_NICAEA}/nicaea_2.5
$ cd build
$ cmake ..
$ make
To get program instructions:
$ ./camelus
Current release: Camelus v1.2
- Improved the computation speed by a factor of 6~7
- Converted the halo array structure into a binned structure, called "halo_map"
- Converted the galaxy tree structure into a binned structure, called "gal_map"
- Added the population Monte Carlo approximate Bayesian computation (PMC ABC) algorithm
- Fixed the bug from calculating halo radii
- Fast weak lensing peak count modeling
- Bartelmann & Schneider (2001) - Phys. Rep., 340, 291
- Fan et al. (2010) - ApJ, 719, 1408
- Lin & Kilbinger (2015a) - A&A, 576, A24
- Lin & Kilbinger (2015b) - Submitted to A&A
- Marin et al. (2011)
- Takada & Jain (2003a) - MNRAS, 340, 580
- Weyant et al. (2013) - ApJ, 764, 116
Authors:
Please feel free to send questions, feedback and bug reports to chieh-an.lin (at) cea.fr.
Check also the package web page.
Go to param and modify .par files to customize parameters.
$ ./camelus 1 z
This gives the values of the mass function from Jenkins et al. (2001) for M from 10^9 to 10^17 [M_sol h^2/Mpc^3].
$ ./camelus 2
This yields a halo list from sampling using customized parameters.
$ ./camelus 3
This creates a peak catalogue and its histogram of S/N values.
A halo list, a galaxy list, a smoothed noise map, a smoothed noisy map will be made as well.
$ ./camelus 4 N
This creates N independent peak lists with the same cosmology and settings from .par files.
Using this command can reduce the computation time, since the cosmological computations are factorized.
$ ./camelus 4 N Omega_m sigma_8
Same as above, but the inputs Omega_m and sigma_8 will overwrite the values from .par files, and creates N independent peak lists.
$ ./camelus 5
ABC computation which requires an observation data that we have provided an example in demo.
Parameters are defined in peakParam.par. Only several summary statistics are available.
This gives posterior samples of Omega_m-sigma_8 constraints. Only this combination is available.
Please check Lin & Kilbinger (2015b) for more details.