Comparison of GMP, Apfloat and Threeway
for the multiplication of large integers
Comparison of three public-domain multiprecision
libraries: BigNum, Gmp and Pari We describe the use of three multiprecision
libraries on two sample problems: compute digits of Pi and compute a recursive
sequence of integers.
Here is a revised version of this comparison.

Numerical evaluation of special functions

Multiplication rapide en LeLisp

An implementation of Schönhage's multiplication algorithm [patch for gmp-4.1.3]
Note: a faster implementation was made with Pierrick Gaudry and
Alexander Kruppa and is available
here.

mpn_mul_fftw.c, a fast integer multiplication
for GMP
using the FFTW package.
Guillermo Ballester Valor made a similar package named YEAFFT.

Implantation de l'algorithme de Schönhage en C avec la bibliotheque BigNum

Implantation de l'algorithme de Schönhage en Maple
FFT Patch for gmp-5.0.1 [README]
# Other interesting links

The GMP home page.

The multi-precision number library CLN from Bruno Haible.

The MPI library
from Michael Fromberger (no longer maintained, but
IMath is)
and the derived LibTomMath
library from Tom St Denis.

The Crack
program from Joris van der Hoeven.

*Multidigit
multiplication for mathematicians* by Dan Bernstein,
and a comparison of
integer multiplication with various libraries

MPSolve 2.0, Multiprecision Polynomial Solver developed by Bini and Fiorentino
in the Frisco project.