Heuristicswiki - pattern database

Related Problems: Rubik's cube, N-Puzzle and Misspelling Type: Utility Description: A Pattern Database stores a collection of solutions to sub-problems that must be achieved to solve the problem. While we normally think of a heuristic as a function computed by an algorithm, any function can also be computed by a table lookup, given sufficient memory. In fact, for reasons of efficiency, heuristic functions are commonly precomputed and stored in memory. In the case of the N-Puzzle, the tiles occupying certain locations are unspecified (blank). A pattern database (PDB): is the set of all patterns which can be obtained by permutations of a target pattern.