NLopt is a library for nonlinear local and global optimization, for functions with and without gradient information. It is designed as as simple, unified interface and packaging of several free/open-source nonlinear optimization libraries. The latest version and a complete manual may be found at the NLopt home page: http://ab-initio.mit.edu/nlopt It is compiled and installed with the standard GNU autoconf/automake commands: ./configure make make install (See `./configure --help` or the `INSTALL` file for other options.) Once it is installed, `#include ` in your C/C++ programs and link it with `-lnlopt -lm`. You may need to use the C++ compiler to link in order to include the C++ libraries (which are used internally by NLopt, even though it has a C API). The minimization function, `nlopt_minimize`, is described in the [man page](http://en.wikipedia.org/wiki/Man_page) (`api/nlopt_minimize.3`, which is installed by `make install`. There are also interfaces for Fortran, Python, Matlab, Octave, OCaml, GNU Guile, GNU R, Lua, and Julia. Interfaces for other languages may be added in the future.