Agile Asynchronous Backtracking for Distributed Constraint Satisfaction Problems

Asynchronous Backtracking is the standard search procedure for distributed constraint reasoning. It requires a total ordering on the agents. All polynomial space algorithms proposed so far to improve Asynchronous Backtracking by reordering agents during search only allow a limited amount of reordering. In this paper, we propose Agile-ABT, a search procedure that is able to change the ordering of agents more than previous approaches. This is done via the original notion of termination value, a vector of stamps labelling the new orders exchanged by agents during search. In Agile-ABT, agents can reorder themselves as much as they want as long as the termination value decreases as the search progresses. Our experiments show the good performance of Agile-ABT when compared to other dynamic reordering techniques.

[1]  M. Silaghi,et al.  Hybridizing ABT and AWC into a polynomial space, complete protocol with reordering , 2001 .

[2]  Christian Bessiere,et al.  DisChoco 2: A Platform for Distributed Constraint Reasoning , 2011 .

[3]  Leslie Lamport,et al.  Distributed snapshots: determining global states of distributed systems , 1985, TOCS.

[4]  David A. McAllester,et al.  GSAT and Dynamic Backtracking , 1994, KR.

[5]  M. Silaghi,et al.  Generalized Dynamic Ordering for Asynchronous Backtracking on DisCSPs , 2006 .

[6]  Amnon Meisels,et al.  Message delay and DisCSP search algorithms , 2006, Annals of Mathematics and Artificial Intelligence.

[7]  C. Bessiere,et al.  DisChoco : A platform for distributed constraint programming , 2006 .

[8]  Makoto Yokoo,et al.  The Distributed Constraint Satisfaction Problem: Formalization and Algorithms , 1998, IEEE Trans. Knowl. Data Eng..

[9]  Boi Faltings,et al.  A Value Ordering Heuristic for Local Search in Distributed Resource Allocation , 2004, CSCLP.

[10]  Amnon Meisels,et al.  Min-domain retroactive ordering for Asynchronous Backtracking , 2009, Constraints.

[11]  Christian Bessiere,et al.  Asynchronous backtracking without adding links: a new member in the ABT family , 2005, Artif. Intell..

[12]  Makoto Yokoo,et al.  Asynchronous Weak-commitment Search for Solving Distributed Constraint Satisfaction Problems , 1995, CP.

[13]  Carmel Domshlak,et al.  Sensor networks and distributed CSP: communication, computation and complexity , 2005, Artif. Intell..

[14]  Amnon Meisels,et al.  Dynamic Ordering for Asynchronous Backtracking on DisCSPs , 2005, CP.