FastDF is a code to set up 1%-accurate particle realisations of the perturbed phase-space distribution of cosmological relic neutrinos.
The code initially samples particles from the perturbed phase-space distribution at high redshift and then evolves them forward by solving the geodesic equation in linear theory. The code uses a symplectic leapfrog integration scheme that explicitly preserves phase-space density. The integration requires pre-computed transfer functions for the first-order metric perturbations, as well as the random phases field used to set up initial conditions.
The code can be compiled with CLASS, which then automatically provides the required transfer functions. It can also be run together with monofonIC to set up dark matter, baryon, and neutrino ICs with a single configuration file and command. See monofonIC.
The code can be configured and compiled with
./autogen.sh
./configure
make
Then check out the examples.
To compile with CLASS, configure with the option --with-class=/path/to/class/. Alternatively, an HDF5 file with perturbation vectors (transfer functions) can be supplied. These can be pre-generated with classex.
- GSL
- FFTW
- HDF5
- MPI
- CLASS (optional)