djbfft 0.76 is faster than FFTW on most computers, notably the Pentium and the UltraSPARC: http://pobox.com/~djb/djbfft.html The range of FFT sizes in djbfft 0.76 is too small to support Mersenne testing directly, but it wouldn't be difficult to build tolerably fast big transforms out of the existing pieces. ---Dan _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers