COSMOS

An open-source code for numerical relativity specialized for PBH formation It is originally translated from SACRA code [Tetsuro Yamamoto, Masaru Shibata, Keisuke Taniguchi(arXiv:0806.4007)] into C++.

Please visit https://sites.google.com/view/cosmoscode/ for a list of publications using COSMOS, and some others.

Changelog

Please check Releases.

- 2026-03-24

• First release: v1.0.0

Documents

Wiki pages are available in https://github.com/cmyoo/cosmos/wiki.

Description

Perfect fluid with linear equation of states & massless scalar field

Non-Cartesian scale-up coordinates

Fixed mesh refinement

OpenMP parallelization

Required system environments

Depending on the environment, one may have to edit the makefile appropriately.

Linux

the default makefile would work with g++ compiler.

Mac

One may have to install an openMP package in addition to a C++ compiler. The std compiler option would have to be altered to an appropriate one (e.g. "-std=c++14")

Note

When performing test calculations on a low-spec PC, such as a laptop PC, the calculation speed (especially for the apparent horizon finder) may drop significantly unless the number of threads for openMP is kept small. For such test calculations, a user may have to limit the number of cores to one or at most a few with "export OMPNUMTHREADS=x" (x: number of threads).

Examples

Three samples are attached in the directories: sample_pert, adiabatic_spherical, and scalar_iso. The detailed physical settings are given in the enclosed pdf files in the directories.

License

COSMOS is licensed under the BSD 3-Clause License. Please see LICENSE for details.

Citation

If you use COSMOS as part of a paper, please cite the following first two papers in which COSMOS is used:

@article{Okawa:2014nda, author = "Okawa, Hirotada and Witek, Helvi and Cardoso, Vitor", title = "{Black holes and fundamental fields in Numerical Relativity: initial data construction and evolution of bound states}", eprint = "1401.1548", archivePrefix = "arXiv", primaryClass = "gr-qc", doi = "10.1103/PhysRevD.89.104032", journal = "Phys. Rev. D", volume = "89", number = "10", pages = "104032", year = "2014" } @article{Yoo:2013yea, author = "Yoo, Chul-Moon and Okawa, Hirotada and Nakao, Ken-ichi", title = "{Black Hole Universe: Time Evolution}", eprint = "1306.1389", archivePrefix = "arXiv", primaryClass = "gr-qc", reportNumber = "OCU-PHYS:382, AP-GR:105, YITP-13-45", doi = "10.1103/PhysRevLett.111.161102", journal = "Phys. Rev. Lett.", volume = "111", pages = "161102", year = "2013" }