There isn't the inverse function for mpz_nextprime which I needed for some recent prime work so I coded one up.
In order to profile parts of this I also added tune/speed support for mpz_nextprime https://github.com/sethtroisi/libgmp/pull/6/files Note that I change the behavior of s->size to mean size bits instead of limbs for for measuring mpz_nextprime, as the function is slow (in the worstcase it can take >5 second for a 1500 bit input, and >90 seconds for a ~2700 bit input) For implementing mpz_prevprime, I tried to reuse as much code as possible with a macro for the function body, I'm not sure how readable it ended up. it also possible this could be speed up if I used separate code for each of the functions, by calculating the negative modulo and using unsigned integers everywhere. I'm open to hearing how folks thinks code could be better reused / structured. Finally for mpz_prevprime(rop, op <= 2) it's not clear what rop should be set to, so I use the smallest prime (2). https://github.com/sethtroisi/libgmp/pull/10/files Patches can be seen at https://patch-diff.githubusercontent.com/raw/sethtroisi/libgmp/pull/6.diff https://patch-diff.githubusercontent.com/raw/sethtroisi/libgmp/pull/10.diff Thanks, Seth _______________________________________________ gmp-devel mailing list gmp-devel@gmplib.org https://gmplib.org/mailman/listinfo/gmp-devel
