Mprime (Cray)

mprime was the software, initially authored by David Slowinski (later versions with Paul Gage), for testing Mersenne numbers for primality on Cray supercomputers.

This software is responsible for the discovery of 7 Mersenne primes. It used Fast Fourier transforms for the multiplication of very large numbers. This represented an advance over the software used by Landon Curt Noll & Laura A. Nickel. Noll had suggested the use of FFT's, but had not implemented them until after his discovery of M26.