Version 2.0.0

9th April 2013

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HSL_MA42_ELEMENT Unsymmetric finite-element system: out-of-core frontal method (real and complex)

HSL_MA42_ELEMENT solves one or more sets of sparse linear unsymmetric unassembled finite-element equations, AX = B, or ATX = B, or AHX = B, by the frontal method. The system may be real or complex (AH denotes the conjugate transpose of A). There are options for automatically ordering the elements, for supplying the elements using a reverse communication interface, for holding the matrix factors in direct-access files, and for preserving a partial factorization.

The n × n coefficient matrix A must have a symmetric structure and must be in elemental form

A = k=1neltA[k],

where A[k] is nonzero only in those rows and columns that correspond to variables in the k-th finite element. The elements must be square elements, with the row indices equal to the column indices. For each k, the user must supply a list specifying which rows/columns of A are associated with A[k] and an array containing the nonzero entries. The right-hand sides B may be supplied in elemental form (that is, B = k=1neltB[k]) or in assembled form.

Precision: At least 8-byte arithmetic is recommended.