Symmetry Breaking as a Prelude to Implied Constraints: A Constraint Modelling Pattern
Symmetry Breaking as a Prelude to Implied Constraints: A Constraint Modelling Pattern
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对称性破缺是隐含约束的前奏:约束建模模式
DOI:
10.1007/978-3-642-37198-1_14
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发表时间:
2004
期刊:
影响因子:
4.8
通讯作者:
Ian Miguel
中科院分区:
文献类型:
--
作者:
Alan M. Frisch;Christopher Jefferson;Ian Miguel
Finite-domain constraint programming can be used to solve a wide range of problems by first modelling the problem as a set of constraints that characterise the problem's solutions, then searching for solutions that satisfy the constraints. Experts often augment models with implied constraints and constraints that break symmetries in the model. An emerging pattern in the modelling process, highlighted and demonstrated here, is that some powerful implied constraints can be derived only after symmetry-breaking constraints have been added. Furthermore, the choice between alternative symmetry-breaking constraints is commonly made by considering either the amount of symmetry broken or the strength of pruning obtained in comparison with the overhead of enforcing the constraints. We demonstrate that the choice should also consider the strength of the implied constraints derivable from the symmetry breaking constraints. We also discuss future automation of the selection of symmetry-breaking constraints and the derivation of implied constraints.