Parallel solution of the multidimensional finite element-spherical harmonics radiation transport equation

A coarse-grain parallel algorithm is described for the solution of the sparse system of linear equations which arise from the application of the finite element-spherical harmonics method to radiation transport problems. The algorithm employs the nested dissection technique to renumber the nodes of the finite element mesh, so as to decompose the resulting global matrix into a number of independent domains, linked by the interface which can then be treated on separate processors. The solution algorithm involves a combination of Cholesky factorization and the preconditioned conjugate gradient scheme that keeps storage to minimum, by solving for spherical harmonics expansion coefficients individually and in parallel. (authors). 5 refs., 3 figs., 3 tabs