The ECLiPSe Constraint Programming System

What is ECLiPSe?

ECLiPSe is an open-source software system for the cost-effective development and deployment of constraint programming applications, e.g. in the areas of planning, scheduling, resource allocation, timetabling, transport etc. It is also ideal for teaching most aspects of combinatorial problem solving, e.g. problem modelling, constraint programming, mathematical programming, and search techniques. It contains several constraint solver libraries, a high-level modelling and control language, interfaces to third-party solvers, an integrated development environment and interfaces for embedding into host environments.


New Paper

January 2021: Paper in AAAI 2020 on Improved filtering for the Euclidean Traveling Salesperson Problem in CLP(FD) by Bertagnon&Gavanelli.

MiniZinc Update

July 2018: Build 7.0#43 comes with updated MiniZinc/FlatZinc interface libraries (these were initially released in Feb'08 as one of the first complete implementations of the MiniZinc modelling language, and allow ECLiPSe users to use MiniZinc together with ECLiPSe's constraint solvers. Furthermore, MiniZinc models can be embedded into ECLiPSe code in order to add user-defined search and I/O facilities to the models).

Release 7.0

January 2018: ECLiPSe 7.0 ready for Download.

New Video

Workshop Introduction to Constraint Logic Programming with ECLiPSe held by Sergii Dymchenko at LambdaConf 2015.

Application Award

February 2015 — ECLiPSe inside: German car manufacturer Opel wins VDA Logistics Award for Supply Chain Optimization tool developed in cooperation with Flexis AG.

New Paper

December 2014: New short paper by Sergii Dymchenko and Mariia Mykhailova on Declaratively solving tricky Google Code Jam problems with ECLiPSe

New Book Edition

January 2014: The text book A Gentle Guide to Constraint Logic Programming via ECLiPSe by Antoni Niederliński (free pdf) is now available in its third edition. A new version of the Python interface by Oreste Bernardi has also been released.

Release 6.1

June 2013: Release 6.1 is available.

Contributed Solver

June 2013: Chris Meudec contributed the Path Traversal Conditions Solver, which finds application in the area of program analysis, symbolic execution, and software testing.

New Interfaces

Sep 2012: Two ECLiPSe interfaces were contributed recently: the Python interface by Oreste Bernardi, and the PHP interface by Andrea Montemaggio.

ICLP Best Paper Award for ECLiPSe-based application paper

July 2011: The application paper Optimal Placement of Valves in a Water Distribution Network with CLP(FD) fetched the Best Paper Award at the ICLP 2011 conference. It explains an application of CLP(FD) to a problem in hydraulic engineering that was developed in ECLiPSe. Congratulations to Marco Gavanelli (a frequent contributor on our mailing list) and his colleagues!

The ECLiPSe Text Book

The book Constraint Logic Programming using ECLiPSe by Krzysztof Apt and Mark Wallace is a practical introduction to constraint programming and to ECLiPSe, with many examples, appropriate for self study or a one-semester course.

Open-Sourcing and Release 5.10

ECLiPSe was open-sourced by Cisco under a Mozilla-style Public Licence in September 2006. The official source repository and other development resources are at The first release made from the open source was release 5.10.