To solve a sparse symmetric system of linear equations. Given a sparse symmetric matrix and an -vector or a matrix , this subroutine solves the system or the system . The matrix need not be deﬁnite. There is an option for iterative reﬁnement.
The method used 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.
There are facilities for returning a Fredholm vector, multiplying a vector by the factors, exploiting sparse right-hand sides, and returning factors in standard format.