Combining Perimeter Search and Pattern Database Abstractions

  title={Combining Perimeter Search and Pattern Database Abstractions},
  author={Ariel Felner and Nir Ofek},
A pattern databaseabstraction (PDB) is a heuristic function in a form of a lookup table. A PDB stores the cost of optimal solutions for instances of abstract problems (subproblems). These costs are used as admissible heuristics for the original problem. Perimeter search (PS) is a form of bidirectional search. First, a breadth-first search is performed backwards from the goal state. Then, a forward search is executed towards the nodes of the perimeter. In this paper we study the effect of… CONTINUE READING