Parallel Schwarz algorithm for the neutron diffusion equation on an MIMD architecture

The parallel Schwarz algorithm for solving the one-group, steady-state neutron diffusion equation and its convergence feature are described. Under-relaxation in pseudo-boundary conditions as an acceleration scheme is introduced in domain decomposition method and its convergence is analyzed. In addition, several iteration strategies which exploit the attractive feature of the under-relaxation scheme in pseudo-boundary conditions are investigated via numerical experiments. The results show that, due to the superior spectral properties of the decomposed problem in parallel calculation, very high speedup (even superlinear) can be obtained and parallel solution is more accurate than sequential one, if adequate iteration strategies are adopted. (orig.)