Minion
Minion is a relatively new constraint solver which is fast and scales well as problem size increases. Minion is a general-purpose constraint solver, with an expressive input language based on the common constraint modelling device of matrix models. Focusing on matrix models supports a lean, highly-optimised implementation. This contrasts with other constraint toolkits, which, in order to provide ever more modelling and solving options, have become progressively more complex at the cost of both performance and usability.
Minion is a black box from the user point of view, deliberately providing few options. This, combined with its raw speed, makes Minion a substantial step towards Puget’s `Model and Run’ constraint solving paradigm.
For more information on Minion and for downloads and updates, please visit: http://constraintmodelling.org/minion/