GNU Prolog is a free implementation (under GPL) of the logic programming language PROLOG. It can compile to native machine code which is extremely fast in execution. Another feature is the included constraint solver.
OptaPlanner optimizes business resource usage. Every organization faces planning problems: provide products or services with a limited set of constrained resources (employees, assets, time and money). OptaPlanner optimizes such planning to do more business with less resources.
OptaPlanner is a
... [More] lightweight, embeddable planning engine written in Java™. It helps normal Java™ programmers solve constraint satisfaction problems efficiently. Under the hood, it combines optimization heuristics and metaheuristics with very efficient score calculation.
OptaPlanner is open source software, released under the Apache Software License. It is 100% pure Java™, runs on any JVM and is available in the Maven Central Repository too. [Less]