Thank you. That is a very nice patch. I have added it. best regards Brian Gough vattervi@msu.edu writes: > Here are diffs to permutation/gsl_permutation.h and > permutation/permutation.c to implement the new functions > gsl_permutation_next and gsl_permutation_prev. > They do the same thing as the .next and .prev methods in the STL. > Vince > >