PARAFISH. A parallel FE-PN neutron solver based on domain-decomposition

The new parallel core solver PARAFISH (PARAllel FInite elements Spherical Harmonics) solves the second-order even-parity form of the time-independent Boltzmann transport equation using an innovative algebraic domain-decomposition (DD) method. The spatio-angular discretization is performed using non-conforming finite elements (FEs) and spherical harmonic expansions (PN method). Besides the DD method and the use of non-conforming F Es, another original feature of PARAFISH is that it enables one processor to handle more than one domain. This enables proper evaluations of the speed-up when varying the number of CPUs with a fixed number of domains. Moreover, when varying the number of domains with a fixed number of CPUs, this enables us to show an inherent acceleration potential, i.e., acceleration without increasing the number of processors. (author)