MPFI is a library for interval arithmetic, which is built upon the MPFR
multiple precision floating-point arithmetic.

MPFI is intended to be a portable library written in C for arbitrary
precision interval arithmetic with intervals represented using MPFR
reliable floating-point numbers. It is based on the GNU MP library and
on the MPFR library.  The purpose of an arbitrary precision interval
arithmetic is on the one hand to get "guaranteed" results, thanks to
interval computation, and on the other hand to obtain accurate results,
thanks to multiple precision arithmetic. The MPFI library is built upon
MPFR in order to benefit from the correct rounding provided, for each
operation or function, by MPFR.  Further advantages of using MPFR are
its portability and compliance with the IEEE 754 standard for
floating-point arithmetic.

WWW: http://perso.ens-lyon.fr/nathalie.revol/software.html
www: http://mpfi.gforge.inria.fr/