The sweep method for radiative transfer in <scp>arepo</scp>

ABSTRACT We introduce the radiative transfer code Sweep for cosmological simulation suite arepo. is a discrete ordinates method in which equation solved under infinite speed of light, steady state assumption by transport sweep across entire computational grid. Since arepo based on an adaptive, unstructured grid, dependency graph induced dependencies grid cells non-trivial. In order to solve topological sorting problem distributed manner, we employ task-based-parallelism approach. The main advantage that cost scales only with size and independent number sources or distribution domain, simulations, where there are large numbers sparsely sources. successfully apply physical tests such as expansion H ii regions, formation shadows behind dense objects, scattering its behaviour presence periodic boundary conditions. addition, measure performance focus highly parallel, large-scale simulations.