# Wiki

# m4ri / M4RI-20111203

# M4RI-20111203 Release Notes

M4RI-20111203 was released on 03 December 2011. It is available at:

http://m4ri.sagemath.org/downloads/

## About M4RI

M4RI is a library for fast arithmetic with dense matrices over GF(2). The name M4RI comes from the first implemented algorithm: The "Method of the Four Russians" inversion algorithm published by Gregory Bard. This algorithm in turn is named after the "Method of the Four Russians" multiplication algorithm which is probably better referred to as Kronrod's method. M4RI implements asymptotically fast matrix multiplication, linear system solving, reduced row echelon forms, PLE decomposition and basic arithmetic. M4RI is used by the Sage mathematics software and the PolyBoRi library. M4RI is available under the General Public License Version 2 or later (GPLv2+).

## Changes in 20111203

### PNG reading/writing

M4RI now uses 1-bit PNG images as matrix file format for storage and exchange. If libpng is available functions are made available for reading and writing such images mzd_to_png/mzd_from_png. See these blog posts for details:

- http://martinralbrecht.wordpress.com/2011/10/15/png-images-ftw/
- http://martinralbrecht.wordpress.com/2011/10/19/challenge-matrices/

### MathJax in Doxygen output

M4RI now uses MathJax to render Tex formulas in the reference manual. See

for the result.

### Specialised Routines for Groebner Basis computations

There is a new experimental repository available at http://bitbucket.org/malb/m4ri-groebner which provides an implementation of linear algebra routines specialised to Groebner basis computations. See

for details

## Supported Platforms

**make check** passes on the following platforms

- x86_64 OSX (bsd.math.washington);
- x86_64 OpenSolaris (hawk);
- x86_64 Linux (sage.math.washington);
- ia64 Linux (iras.skynet);
- x86 Linux (Pentium 4, cicero.skynet);

Updated