I'm looking for a library or individual package which provides convenient optimization subroutine for Fortran, any suggestions?
I'm testing the codes from Numerical Recipe, downhill simplex method and direction-set method, but the input-output interface is not convenient for chi-squared function, because we generally need to find the minimum of chi-squared function within a cube-like parameter space. Thus, I need a more convenient utility especially for least chi-squared problem.
