INTERLEAVED BACKTRACKING IN DISTRIBUTED CONSTRAINT NETWORKS

Abstract

The adaptation of software technology to distributed environments is an important challenge today. In this work we combine parallel and distributed search. By this way we add the potential speed-up of a parallel exploration in the processing of distributed problems. This paper extends DIBT, a distributed search procedure operating in distributed constraint networks.11 The extension is threefold. First, the ordered hierarchies used during backtracking are extended to remove partial orders. Second the procedure is updated to face delayed information problems upcoming in heterogeneous (We would like to thank here M. Yokoo for rising this potential problem.)Third, the search is extended to simultaneously explore independent parts of a distributed search tree. The first and third points were first presented in 1999.7 The third improvement introduces parallelism into distributed search, which brings to Interleaved Distributed Intelligent BackTracking (IDIBT). Our results show that 1) insoluble problems do not greatly degrade performance over DIBT and 2) super-linear speed-up can be achieved when the distribution of solutions is non-uniform.