The module HSL_MA42 solves one or more sets of sparse linear equations, or , 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 may be input by the user in either of the following ways:
In both cases, the coeﬃcient matrix and right-hand side(s) are of the form
In case (i), the summation is over ﬁnite elements. The matrix is nonzero only in those rows and columns which correspond to variables in the -th element. The vector is nonzero only in those rows which correspond to variables in element .
In case (ii), the summation is over equations and and are nonzero only in row .