ASA047 is a FORTRAN77 library which seeks to minimize a scalar function of several variables using the Nelder-Mead algorithm, by R ONeill.
ASA047 is Applied Statistics Algorithm 47. Source code for many Applied Statistics Algorithms is available through STATLIB.
ASA047 is available in a C version and a C++ version and a FORTRAN77 version and a FORTRAN90 version and a MATLAB version and a Python version.
COMPASS_SEARCH, a FORTRAN77 library which seeks the minimizer of a scalar function of several variables using compass search, a direct search algorithm that does not use derivatives.
DQED, a FORTRAN77 library which solves constrained least squares problems.
MINPACK, a FORTRAN90 library which solves systems of nonlinear equations, or the least squares minimization of the residual of a set of linear or nonlinear equations.
NL2SOL, a FORTRAN77 library which implements an adaptive nonlinear least-squares algorithm.
PRAXIS, a FORTRAN77 library which minimizes a scalar function of several variables.
TEST_OPT, a FORTRAN90 library which defines test problems requiring the minimization of a scalar function of several variables.
TOMS178, a FORTRAN77 library which optimizes a scalar functional of multiple variables using the Hooke-Jeeves method.
TOMS611, a FORTRAN77 library which solves problems in unconstrained minimization.
Original FORTRAN77 version by R ONeill; This FORTRAN77 version by John Burkardt.
You can go up one level to the FORTRAN77 source codes.