63.1.3 The MPFR library

MPFR is a portable library for arbitrary precision arithmetic on floating-point numbers, based on the GMP library. It works similar to the MPF module of GMP, however the main differences with MPF are:

• the mpfr code is portable, i.e. the result of any operation does not depend on the machine word size mp_bits_per_limb (32 or 64 on most machines);
• the precision in bits can be set exactly to any valid value for each variable;
• MPFR provides the four rounding modes from the IEEE 754-1985 standard.

In particular, with a precision of 53 bits, mpfr should be able to exactly reproduce all computations with double-precision machine floating-point numbers (double type in C). Furthermore, MPFR comes with a heap of useful functions over the reals, like logarithms, trigonometrical functions and so forth.

The MPFR library is released under the GNU LGPL and can be obtained from http://www.mpfr.org. Please refer also to their documentation, and especially their instructions on how to install it.

Especially note that we currently do only support the standalone version of MPFR, and not the one distributed with GMP.