UnSNAP: A Mini-App for Exploring the Performance of Deterministic Discrete Ordinates Transport on Unstructured Meshes

Solving the deterministic discrete ordinates neutral particle transport equation is a computationally expensive application. On an unstructured mesh, the discontinuous Galerkin finite element method is used for discretisation of the spatial domain. Additionally, an upwind dependency is applied forming wavefront sweeps across the spatial mesh for each iteration of the solve. We present a new mini-app, UnSNAP, which can be used to investigate the performance of arbitrarily high-order finite element unstructured transport on modern architectures. A new schedule appropriate for such architectures is presented. Finally, we show performance results for the mini-app on CPUs with high numbers of cores.