A open-source ray tracing code to compute integrated cosmological observables on the fly in AMR N-body simulations. Unlike conventional ray tracing techniques, our code takes full advantage of the time and spatial resolution attained by the N-body simulation by computing the integrals along the line of sight on a cell-by-cell basis through the AMR simulation grid. Moroever, since it runs on the fly in the N-body run, our code can produce maps of the desired observables without storing large (or any) amounts of data for post-processing. The ray tracing methodology presented here can be used in several cosmological analysis such as Sunyaev-Zel’dovich and integrated Sachs-Wolfe effect studies as well as modified gravity. Our code can also be used in cross-checks of the more conventional methods, which can be important in tests of theory systematics in preparation for upcoming large scale structure surveys.
The code has ben tested and run on COSMA, which uses CentOS 7.6 with a 3.10 Linux kernel.
Prerequisites:
- A Fortran compiler
- CMake
- Intel MPI (2018)
- IntelComp (2018)
To build the Fortran BMI bindings from source with cmake, run
$ cd ./src/bin
$ make
You can quickly test your installation by executing:
$ cd bin
$ make
$ cd ..
$ bin/ramses1d namelist/tube1d.nml
Initial condition can be generated with 2LPTic.
The simulation results can be analysed through Astrild.