To solve one or more set of sparse unsymmetric linear equations from ﬁnite-element applications, using a multifrontal elimination scheme. The matrix must be input by elements and be of the form
where is nonzero only in those rows and columns that correspond to variables of the nodes of the -th element. Optionally, the user may pass an additional matrix of coeﬃcients for the diagonal. is then of the form
The right-hand side should be assembled through the summation
before calling the solution routine.