论文信息 - On Generators of Random Quasigroup Problems

On Generators of Random Quasigroup Problems

Problems that can be sampled randomly are a good source of test suites for comparing quality of constraint satisfaction techniques. Quasigroup problems are representatives of structured random problems that are closer to real-life problems and hence more suitable for benchmarking. In this paper, we describe in detail generators for Quasigroup Completion Problem (QCP) and Quasigroups with Holes (QWH). In particular, we study an improvement of the generator for QCP that produces a larger number of satisfiable problems by using propagation through the all-different constraint. We also re-formulate the algorithm for generating QWH that is much faster than the original generator. Finally, we provide an experimental comparison of all presented generators.

Roman Barták

[1] D. Shmoys,et al. The Promise of LP to Boost CSP Techniques for Combinatorial Problems , 2002 .

[2] Bart Selman,et al. Generating Satisfiable Problem Instances , 2000, AAAI/IAAI.

[3] Bart Selman,et al. Problem Structure in the Presence of Perturbations , 1997, AAAI/IAAI.

[4] T. Walsh,et al. Arc Consistency and Quasigroup Completion , 2006 .

[5] Roman Barták,et al. Limited assignments: a new cutoff strategy for incomplete depth-first search , 2005, SAC '05.

[6] Mats Carlsson,et al. An Open-Ended Finite Domain Constraint Solver , 1997, PLILP.

[7] D. Shmoys,et al. Completing Quasigroups or Latin Squares: A Structured Graph Coloring Problem , 2002 .

[8] Jean-Charles Régin,et al. A Filtering Algorithm for Constraints of Difference in CSPs , 1994, AAAI.

[9] Toby Walsh,et al. Random Constraint Satisfaction: Theory Meets Practice , 1998, CP.

[10] Charles J. Colbourn,et al. The complexity of completing partial Latin squares , 1984, Discret. Appl. Math..

[11] P. Matthews,et al. Generating uniformly distributed random latin squares , 1996 .

[12] Manuel Cebrián,et al. Channeling Constraints and Value Ordering in the QuasiGroup Completion Problem , 2003, IJCAI.

[13] Alexander Russell,et al. Approximating Latin Square Extensions , 1996, Algorithmica.

[14] Toby Walsh,et al. Interleaved and Discrepancy Based Search , 1998, ECAI.