Constraint logic programming: Difference between revisions

Revision as of 16:23, 30 June 2011

Revision as of 22:36, 10 August 2011

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The second use of the labeling literal is to actually determine an evaluation of the variables that satisfies the constraint store. Without the labeling literal, variables are assigned values only when the constraint store contains a constraint of the form <code>X=value</code> and when local consistency reduces the ___domain of a variable to a single value. A labeling literal over some variables forces these variables to be evaluated. In other words, after the labeling literal has been considered, all variables are assigned a value.

Typically, constraint logic programs are written in such a way labeling literals are evaluated only after as muchmany constraints as possible have been accumulated in the constraint store. This is because labeling literals enforce search, and search is more efficient if there are more constraints to be satisfied. A [[constraint satisfaction problem]] is typical solved by a constraint logic program having the following structure:

solve(X):-constraints(X), labeling(X)