"GMP is a free library for arbitrary precision arithmetic, operating on signed integers, rational numbers, and floating point numbers" -- stands for "GNU Multiple Precision" arithmetic library, lives at http://www.swox.com/gmp/. gmpy (General Multiprecision PYthon arithmetical stuff) is (initially) a Python 2.0 module interfacing to GMP 3.1, homepage http://gmpy.sourceforge.net/, project summary page at http://sourceforge.net/projects/gmpy/. Current gmpy version is 0.6 (pre-alpha): fully exposes GMP's rich functionality for mpz (unlimited precision integers), mostly exposes mpf (multiple precision floats), mpq (rational numbers), random-number generation; not yet mpfr (enhanced version of multiple-precision floats). (Changes wrt 0.5: substantial speedup of MPQ via caching [& alloca in MSVC++], workaround for GMP scan0/scan1 bug, more precise conversions & better tracking of mpf precision, many minor additions, cleanups, doc updates, more tests. Changes wrt 0.4: completely exposes MPZ, adds MPQ, random numbers, more unit-tests & timing/examples, doc updates, sundry minor cleanups. Changes wrt 0.3: docstrings added; minor cleanups, speedups, additions; added C API and sample module; added timing/example scripts. Changes wrt 0.2: substantial speedups, additions, and cleanups. Changes wrt 0.1: bugfixes, additions, speedups...). Gmpy sources (needed for ALL platforms, as they include documentation, unit-tests, distutils' setup.py) are at: http://download.sourceforge.net/gmpy/gmpy-sources-06.zip (for non-Win32 platforms, you'll have to download and install GMP 3.1.1 separately before you can build gmpy from these sources, see http://www.swox.com/gmp/#DOWNLOAD). Gmpy binaries for Win32 / MSVC++6 are available at: http://download.sourceforge.net/gmpy/gmpy-win32-library.zip Lundy's port of GMP.LIB 3.1.1, and GMP.H (only needed if you intend to rebuild GMPY.PYD from sources with Microsoft VC++6 on Win32). ftp://ftp.whiterose.net/pub/lundman/ is also OK for this (but you have to know exactly what to get from there...). http://download.sourceforge.net/gmpy/gmpy-win32-binary-05.zip pre-built gmpy.pyd (release: pre-alpha 0.5), only needed on Win32 and if you do NOT intend to rebuild GMPY.PYD. Alex