GNU MP is a library for arbitrary precision arithmetic, operating on
signed integers, rational numbers, and floating point numbers.  It has a
rich set of functions, and the functions have a regular interface.

GNU MP is designed to be as fast as possible, both for small operands and
for huge operands.  The speed is achieved by using fullwords as the basic
arithmetic type, by using fast algorithms, by carefully optimized assembly
code for the most common inner loops for a lots of CPUs, and by a general
emphasis on speed (instead of simplicity or elegance).

The speed of GNU MP is believed to be faster than any other similar
library. The advantage for GNU MP increases with the operand sizes for
certain operations, since GNU MP in many cases has asymptotically faster
algorithms.

The mpfr library is no longer bundled with gmp, but exists as a separate
package instead.