UMFPACK Version 2.2 is a package for solving systems of sparse linear systems,
Ax=b, where A is sparse and can be unsymmetric.  It is written in ANSI Fortran
77.  There are options for choosing a good pivot order, factorizing a
subsequent matrix with the same pivot order and nonzero pattern as a
previously factorized matrix, and solving systems of linear equations with
the factors (with A, L, or U; or with their transposes in the single/double
precision versions).  Iterative refinement, with sparse backward error
estimates, can be performed.  Single and double precision, complex, and
complex double precision (complex*16) routines are available.  (Note that
complex*16 is not ANSI Fortran-77, but is a common extension to it).

For more information
--------------------

For more information, see T. A. Davis and I. S. Duff, "An
unsymmetric-pattern multifrontal method for sparse LU factorization",
SIAM J. Matrix Analysis and Applications (to appear), also
technical report TR-94-038, CISE Dept., Univ. of Florida,
P.O. Box 116120, Gainesville, FL 32611-6120, USA.  The method used
here is a modification of that method, described in T. A. Davis,
"A combined unifrontal/multifrontal method for unsymmetric sparse
matrices," TR-94-005, and in T. A. Davis and I. S. Duff, (same title),
TR-95-020.  (Technical reports are available via WWW at
http://www.cis.ufl.edu/).  The (unsymmetric) approximate degree update
algorithm used here has been incorporated into a symmetric approximate
minimum degree ordering algorithm, described in P. Amestoy, T. A. Davis,
and I. S. Duff, "An approximate minimum degree ordering algorithm",
SIAM Journal on Matrix Analysis and Applications (to appear, also TR-94-039).
The approximate minimum degree ordering algorithm is implemented as MC47
in the Harwell Subroutine Library (MC47 is not used in UMFPACK).
Also take a look at our World Wide Web home pages:
        Tim Davis:  http://www.cis.ufl.edu/~davis
                    (also email: davis@cis.ufl.edu).
        Iain Duff:  http://www.cis.rl.ac.uk/people/isd/contact.html
______________
	Timothy A. Davis and Iain S. Duff.  Copyright (C) 1997.