The cosmological simulation code CONCEPT 1.0

Abstract

ABSTRACT We present version 1.0 of the cosmological simulation code $\rm{{\small CO}{{\small N}}{\small CEPT}}$, designed for simulations of large-scale structure formation. $\rm{{\small CO}{\rm{\small N}}{\small CEPT}}$ 1.0 contains a P3M gravity solver, with the short-range part implemented using a novel (sub)tiling strategy, coupled with individual and adaptive particle time-stepping. A primary objective of $\rm{{\small CO}{\rm{\small N}}{\small CEPT}}$ is ease of use. To this end, it has built-in initial condition generation and can produce output in the form of snapshots, power spectra, and direct visualizations. $\rm{{\small CO}{\rm{\small N}}{\small CEPT}}$ is the first massively parallel cosmological simulation code written in Python. Despite of this, excellent performance is obtained, even comparing favourably to other codes such as gadget at similar precision, in the case of low to moderate clustering. By means of power-spectrum comparisons we find extraordinary good agreement between $\rm{{\small CO}{\rm{\small N}}{\small CEPT}}$ 1.0 and gadget. At large and intermediate scales the codes agree to well below the per mille level, while the agreement at the smallest scales probed ($k \sim 13\ h\, {\rm Mpc}^{-1}$) is of the order of 1 per cent. The $\rm{{\small CO}{\rm{\small N}}{\small CEPT}}$ code is openly released and comes with a robust installation script as well as thorough documentation.