SYMPHONY is an open-source solver for mixed-integer linear programs (MILPs)
written in C. It can be used in four different main modes:
* As a callable library through either the native C interface or through the
  Osi.
* As an interactive solver using a command-line interface.
* As a framework to build customized solvers for specific problem classes.
* Through a number of different modeling languages: AMPL, GMPL, GAMS, PuLP.

WWW: https://projects.coin-or.org/SYMPHONY