What is Abacus?

Abacus is a high-accuracy, high-performance cosmological N-body simulation code. It is optimized for GPU architectures and for large volume, moderately clustered simulations. It is extremely fast: we clock over 30 million particle updates per second on commodity dual-Xeon, dual-GPU computers and nearly 70 million particle updates per second on each node of the Summit supercomputer. But it is also extremely accurate: typical force accuracy is below \(10^{-5}\) and we are using global timesteps, so the leapfrog timesteps away from the cluster cores are much smaller than the dynamical time.

Abacus has been described in several publications. See Papers & Citation for a list of these papers.

CompaSO, the Abacus on-the-fly halo finder, is described on the CompaSO Halo Finder page.