"PrimeForm" (the former name of this program) allows probable prime tests of arbitrary expressions, and deterministic classical tests wherever possible. The current version, PrimeForm/GW, is available here for many x86 platforms, including Windows, Linux, and Mac. It uses the George Woltman libraries (gwnum), as developed for the GIMPS project, for high-speed PRP and classical testing of arbitrary forms. There are both 32-bit and 64-bit builds available. You will also find a WIndows GUI version of PFGW, called WinPFGW, that can run on Windows XP, Windows Vista, and Windows 7.

OpenPFGW is an open source project. The source code is freely available and all contributions are welcome. You can find discussions on pfgw capabilities and usage. You can find discussions on pfgw releases.

The previous version of the program, "PrimeForm for Windows", is now obsolete. It is a sister program to Yves Gallot's proth.exe and uses the same mathematics libraries as proth.exe. It is still available for users who prefer a GUI, but it is several times slower than pfgw.

Many thanks to George Woltman and Yves Gallot for providing their wonderful mathematics libraries for the respective program versions. Thanks to Chris Caldwell and Preda Mihailescu for optimizations of the classical tests, thanks also go to Chris for supporting the p?? prover codes in the top 5000 database. Above all, thanks and appreciation go to the numerous mathematicians and computer scientists whose methods are used by the program.