The ad hoc manner in which direct manipulation interfaces have been designed and implemented restricts the types of interactive controls. This dissertation presents a new approach for a systematic method to implement flexible, combinable interactive controls.

Project to develop and explore using advanced constraint methods to make user interface software. Constraints as a general computational technique allow declaring a set of relationships between entities. A constraint satisfaction system is employed to automatically ensure that the relationships hold under changing conditions.

Designing and specifying 3D scenes is a tedious, time consuming process that often degenerates into trial and error. We propose a new way to form virtual worlds based on geometric modeling constraints and higher-level modeling abstractions.

Description of book, Academic Press, release 1993: programs from book.

Description of book, MIT Press, release March 1998: programs from book, slides for courses for use with book.

Java applet that solves non-linear real arithmetic constraints.

Incremental constraint solving toolkit, efficiently solves systems of linear equalities, inequalities. Constraints can be requirements or preferences. Client code specifies constraints to maintain, and the solver updates constrained variables to have values that satisfy the constraints.

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.

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

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, extensive links. Clearly the product of much work.

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 and viewer, via solving all the constraints.

Covering all aspects of computing with constraints; on paper or online, via Kluwer Online; fee required.

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

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

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]

Definitions, applications, libraries, links.

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.

Generating an Amalgam of Real-time, Novel Editors and Toolkits; developed by User Interface Software Group, Human Computer Interaction Institute, School of Computer Science, Carnegie Mellon University. Free: public domain.

Frequently Asked Questions about Garnet user interface development environment for Common Lisp and X11 or Macintosh developed by User Interface Software Group, Human-Computer Interaction Institute, Carnegie Mellon University.

Personal page of Garnet inventor and lead researcher. Describes Garnet motives, rationale.

ResearchIndex: Constraints provide a useful mechanism to maintain relations in user interface toolkits. Garnet is a widely used user interface toolkit with high functionality, based on one way, required constraints. Multi-Garnet extends this by adding support for multi-way constraints and hierarchies.

University course: definitions, lecture notes, books, language descriptions, links.

Online tutorial/textbook for beginners to the area of constraint programming. This area is of the set of less known software technologies, but is evolving rapidly and has a growing, significant commercial interest.

Building a user-friendly Graphical User Interface (GUI) with languages like C++ or Java is difficult and time-consuming, because such languages demand specifying many details about the geometric data of layout, the sequence in which items are displayed, the sequence in which events are handled.

Free constraint software developed by Institute for New Generation Computer Technology (ICOT), Japan: Constraint MGTP (CMGTP) model generation theorem prover (MGTP), MGTP-G, KLIC, some cu-Prologs, and documents. FTP site.

ILOG's constraint-programming optimization engine, providing cutting-edge optimization technology and an optimization library for workforce scheduling, league scheduling, sequencing, configuration, dispatching and resource-allocation applications with logical constraints.

Java library for constraint programming. It provides technology for solving satisfaction and optimization problems including: scheduling, planning, routing, time tabling, resource allocation, configuration and many others. KCS includes a solver on boolean, integer and set domains, global constraints. KCS also includes a local search solver useful for solving huge problems when exact methods are too slow.

FTP download, no separate documentation.

ResearchIndex: In the last 20 years, many algorithms and heuristics were developed to find solutions in constraint networks. Their number increased so much that it quickly became vital to compare performance to propose a small number of good methods.

Attempt to make a system that is easier to learn and use than anything available to novice programmers today: HANDS: Human-centered Advances for Novice Development of Software. School of Computer Science, Carnegie Mellon University; NSF funded.

Frameworks and algorithms for analyzing and transforming scientific programs; 2 major components: the Omega test system to manipulate sets of affine constraints over integer variables; and developing frameworks to analyze and transform programs.

Brown University, US. Some constraint papers.

Book by Vijay Saraswat and Pascal Van Hentenryck. Description of book, MIT Press: collection of 23 original papers is first effort to assemble the work of constraint programming researchers scattered across the world in multiple disciplines.

The Constraint Imperative Programming CIP family of languages integrates constraints and imperative, object oriented programming. Besides merging useful features of both paradigms, such integration has synergistic effects.

2001 November 26 - December 1, Paphos, Cyprus.

Very brief, trivial explanation of the first constraint language, and its author.

Free, reusable iterative optimization library for combinatorial problems with fuzzy constraints. GNU LGPL.

Potent new optimization technology for multidimensional optimization practical problems with continuous, breaking nondifferentiative and stochastic goal functions, 100 or more variables, cuts the cost and time to creation of new technical systems.

Simulation laboratory: environment to build dynamic models of experiments in geometry, physics: simulations of constrained geometric objects, simple electrical circuits, mechanical linkages, bridges under load. Can use methods developed for these domains to model other sorts of objects: graphical calculator, documents with constraints on layout and contents.

Supports exploration of constraint-based user interfaces; consists of a set of classes that define constraints and constrainable objects called things. Incremental constraint satisfier, module compiler, construction-set style user interface, many tools, extensible set of primitive user interface building blocks.

Several very interesting projects: GENET; Guided Local Search, GLS; Guided Genetic Algorithm, GLS; Adaptive Constraint Satisfaction, ACS; Computer-Aided Constraint-Programming, CACP.

In the Department of Computer Science: descriptions, research, members, publications, links.

Constraints research group, Department of Computer Science and Engineering. Home of DeltaBlue, Cassowary. Neat constraint Java Applet demonstrates a theorem about quadrilaterals.