NLopt is a library for nonlinear local and global optimization, for functions with and without gradient information. It is designed as a simple, unified interface and packaging of several free/open-source nonlinear optimization libraries.

The latest release can be downloaded from the NLopt releases page on Github, and the NLopt manual is hosted on readthedocs.

NLopt is compiled and installed with the CMake build system (see CMakeLists.txt file for available options):

git clone git://github.com/stevengj/nlopt
cd nlopt
mkdir build
cd build
cmake ..
make
sudo make install

(To build the latest development sources from git, you will need SWIG to generate the Python and Guile bindings.)

Once it is installed, #include <nlopt.h> in your C/C++ programs and link it with -lnlopt -lm. You may need to use a C++ compiler to link in order to include the C++ libraries (which are used internally by NLopt, even though it exports a C API). See the C reference manual.

There are also interfaces for C++, Fortran, Python, Matlab or GNU Octave, OCaml, GNU Guile, GNU R, Lua, Rust, and Julia. Interfaces for other languages may be added in the future.