To solve a sparse symmetric system of linear equations. Given a sparse symmetric matrix and an -vector (or an matrix ), this subroutine solves the system (). The matrix need not be deﬁnite.
The multifrontal method is used. It is a direct method based on a sparse variant of Gaussian elimination.
The matrix is optionally prescaled by using a symmetrization of the MC64 scaling. Other ordering options are provided including hooks to MeTiS. The user can avoid additional ﬁll-in to that predicted by the analysis by using static pivoting.