Version 5.2.0

2nd August 2013

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HSL_MA57 Sparse symmetric system: multifrontal method

To solve a sparse symmetric system of linear equations. Given a sparse symmetric matrix A = {aij}n×n and an n-vector b or a matrix B = {bij}n×r, this subroutine solves the system Ax = b or the system AX = B . The matrix A 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.