sci UMFPACK is a set of routines for solving unsymmetric sparse linear systems, Ax=b, using the Unsymmetric MultiFrontal method. Written in ANSI/ISO C, with a MATLAB (Version 6.0 and later) interface. Appears as a built-in routine (for lu, backslash, and forward slash) in MATLAB. Includes a MATLAB interface, a C-callable interface, and a Fortran-callable interface.