### HSL_MA48 Sparse unsymmetric system: driver for conventional direct
method

To solve a sparse unsymmetric system of linear equations. Given a sparse matrix
$A={\left\{{a}_{ij}\right\}}_{m\times n}$ and a vector
$b$, this subroutine
solves the system $Ax=b$
or the system ${A}^{T}x=b$.
The matrix $A$
can be rectangular. There is an option for iterative reﬁnement and return of error
estimates.

This Fortran 95 code oﬀers additional features to the Fortran 77 code MA48. For
example, there is an option to analyse the matrix and generate the factors with a
single call. The storage required for the factorization is chosen automatically and, if
there is insuﬃcient space for the factorization, more space is allocated and the
factorization is restarted. The Fortran 95 version also returns the number of entries
in the factors and has facilities for computing the determinant when the
matrix is square and for identifying the rows and columns that are treated
specially when the matrix is singular or rectangular. Some of the integers are
long integers so that the size of the factors is not constrained by the 32-bit
limit.