Extended Partial-Order Dynamic Backtracking Algorithm for Dynamically Changed Environments

Abstract

Unlike constructive approaches in which a partial assignment to the variables is incrementally extended, repair approaches start with an inconsistent assignment (e.g. old solution) and search through the space of possible repairs. In this paper, we propose an Extended Partial-order Dynamic Backtracking (EPDB) algorithm for dynamically changed environments. The EPDB allows dynamic CSPs to be dealt efficiently according to based-repair heuristic approaches. A past solution can be repaired using retroactive data structures: safety conditions and no goods, saved previously in Partial-order Dynamic Backtracking process. We evaluate our algorithm on synthetic and real problems, and experimental results show that the proposed algorithm outperforms the original algorithm PDB, in terms of run-time and constraints checks.