Introduction

The oldest work in constraint programming was by Ivan E. Sutherland with Sketchpad (published 1963). In his Ph.D. thesis, Sketchpad Sutherland used constraints to tell computer what to do. With this the first concept of the constraint as a method of specifying details of the geometry of the picture was introduced. Constraint programming is a programming paradigm where relations between variables can be stated in the form of constraints. Constraints differ from the common primitives of other programming languages in that they do not specify a step or sequence of steps to execute but rather the properties of a solution to be found. Constraints are usually embedded within a programming language or provided via separate software libraries.Constraint programming is a rapidly maturing technology, and several commercial tools are available. The techniques are applicable to a wide range of scheduling and resource allocation problems, and there are already a number of successfully fielded applications.

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