Scalable angular adaptivity for Boltzmann transport [article]

S. Dargaville, A.G. Buchan, R.P. Smedley-Stevenson, P.N Smith, C.C. Pain
2019 arXiv   pre-print
This paper describes an angular adaptivity algorithm for Boltzmann transport applications which for the first time shows evidence of O(n) scaling in both runtime and memory usage, where n is the number of adapted angles. This adaptivity uses Haar wavelets, which perform structured h-adaptivity built on top of a hierarchical P_0 FEM discretisation of a 2D angular domain, allowing different anisotropic angular resolution to be applied across space/energy. Fixed angular refinement, along with
more » ... ar and goal-based error metrics are shown in three example problems taken from neutronics/radiative transfer applications. We use a spatial discretisation designed to use less memory than competing alternatives in general applications and gives us the flexibility to use a matrix-free multgrid method as our iterative method. This relies on scalable matrix-vector products using Fast Wavelet Transforms and allows the use of traditional sweep algorithms if desired.
arXiv:1901.04929v1 fatcat:rkpzwy4dtvbmddjbls6p5k2sgi