To solve 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. is nonzero only in those rows and columns which correspond to variables in the -th element. 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 .