Version 1.3.0

10th April 2013

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HSL_MA42 Sparse unsymmetric system: out-of-core frontal method

The module HSL_MA42 solves one or more sets of sparse linear equations, Ax = b or ATx = b, by the frontal method, optionally using direct-access files for the matrix factors. Use is made of high level BLAS kernels. The code has low in-core memory requirements. The matrix A may be input by the user in either of the following ways:

(i) by elements in a finite-element calculation,
(ii) by equations (matrix rows).

In both cases, the coefficient matrix and right-hand side(s) are of the form

A = k=1mA(k),b = k=1mb(k).

In case (i), the summation is over finite elements. The matrix A(k) is nonzero only in those rows and columns which correspond to variables in the k-th element. The vector b(k) is nonzero only in those rows which correspond to variables in element k.

In case (ii), the summation is over equations and A(k) and b(k) are nonzero only in row k.