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Developer(s) Timothy A. Davis
Initial release January 1994
Stable release 5.6.2 / April 25, 2013; 21 months ago (2013-04-25)
Development status Active
Written in C
Operating system Cross-platform
Type Mathematics, Linear Algebra
License GNU Lesser General Public License or BSD-License

UMFPACK /ˈʌmfpæk/ is a set of routines for solving sparse linear systems of the form Ax=b, using the Unsymmetric MultiFrontal method (Matrix A is not required to be symmetric). Written in ANSI/ISO C and interfaces with

It appears as a built-in routine (for lu, backslash, and forward slash) in MATLAB, and includes a MATLAB interface, a C-callable interface, and a Fortran-callable interface. Note that "UMFPACK" is pronounced in two syllables, "Umph Pack". It is not "You Em Ef Pack".

The BLAS: Basic Linear Algebra Subprograms[edit]

UMFPACK has installation options to use the many versions of the BLAS, or no BLAS at all. The BLAS is what UMFPACK relies on to get high performance on a wide range of computers. If at all possible, use the BLAS. If your BLAS uses 64-bit integers, compile with -DBLAS64. You can also edit the UFconfig.h (SuiteSparse_config.h starting from version 4.0.0) file as needed to include this definition.


The license of UMFPACK has changed in the last two years by a BSD license to LGPL, and finally in the last version 5.2 to a GPL license. Some versions of the software have been retroactively placed under the LGPL, so you can be found on the net different licensed versions. UMFPACK will tackle by MATLAB as the standard solution method used for sparse matrices.

External links[edit]