By AEM Design: a source code for minimizing the maximum of a set of smooth objective functions subject to general smooth constraints. Two versions, written in portable: Fortran 77 (FFSQP), standard C (CFSQP). Both are tested and run on most platforms.

Home of Explanation-based Constraint Programming. Definitions, applications, libraries, links.

Constraint solver benchmark, in Java; about 1000 lines of code. DeltaBlue first implemented by John Maloney at University of Washington, translated to many languages: C, C++, Java; Smalltalk. [Sun Microsystems Labs]

Efficient, incremental local propagation constraint solver. Like most local propagation algorithms, it cannot accommodate cyclic constraints. University of Washington site.

For incremental dataflow constraint solver, implemented in varied languages, each in a subdirectory named after the language: C DEC, C SUN4; Common Lisp, Smalltalk.

Covering all aspects of computing with constraints; on paper or online; fee required.

Constraints can specify desired layout of web documents, and behavior of embedded applets: 2 system architectures where author and viewer can make layout constraints, needed and optional. Final appearance of page comes from negotiation between author ...

Holds comp.constraints FAQ, pages of constraint-related pointers, source code for various systems, benchmarks, directory of people interested in constraints, constraint bibliographies, collection of online papers, links. Clearly the product of much work.

Page about Alan Borning, a leading researcher in the field. From NSF conference ISGW '97: Interactive Systems Grantees Workshop.

High-level programming language to write constraint systems; makes it easy to define constraint reasoning: simplification and propagation, and incremental solving (satisfaction) of constraints. Run and test CHR online; do a demo, try it now.