GNU MPRIA is intended to be a portable mathematical library written in C for Multi-Precision Rational Interval Arithmetic computations. It is free software under the GNU General Public License.

The basic principle of rational interval arithmetic consists in enclosing every number by a rational interval containing it: each number is stored as its lower and upper endpoints and these bounds are rational numbers; their absolute difference measures the precision. The purpose is on the right hand to obtain guaranteed results, thanks to interval computation, and on the left hand to compute accurate results, thanks to arbitrary precision arithmetic.

The arithmetic operations are extended for interval operands in such a way that the exact result of the operation belongs to the computed rational interval.

The GNU MPRIA library is built upon the GMP library for operating on rational numbers; see

The GNU MPRIA library was inspired by the Multi-Precision Floating-point Interval arithmetic library (MPFI) available at The MPFI library is based on the MPFR library for operating on floating-point numbers (see, itself built upon GMP. The corresponding software page written by Nathalie Revol gives a more detailed introduction to interval arithmetic, a succinct bibliography on the subject and some related links.

Downloading GNU MPRIA

MPRIA can be found on the main GNU ftp server: (via HTTP) and (via FTP). It can also be found on the GNU mirrors; please use a mirror if possible.


Documentation for MPRIA is available online, as is documentation for most GNU software. You may also find more information about MPRIA by running info mpria, or by looking at /usr/share/doc/mpria/, /usr/local/doc/mpria/, or similar directories on your system.

Mailing lists

The discussion list for GNU MPRIA is bug-mpria, and it is used to discuss all aspects of GNU MPRIA, including support questions, development and enhancement requests, bug reports, suggestions and patches.

Announcements about MPRIA and most other GNU software are made on info-gnu (archive).

Getting involved

Development of MPRIA, and GNU in general, is a volunteer effort, and you can contribute. For information, please read How to help GNU. If you'd like to get involved, it's a good idea to join the discussion mailing list (see above).

Test releases
Trying the latest test release (when available) is always appreciated. Test releases of MPRIA can be found at (via HTTP) and (via FTP).
For development sources, issue trackers, and other information, please see the MPRIA project page at
MPRIA is currently being maintained by Jérôme Benoit. Please use the mailing lists for contact.


GNU MPRIA is Copyright © 2014-2016 Jérôme Benoit

GNU MPRIA is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.