SymChaff: exploiting symmetry in a structure-aware satisfiability solver

Sabharwal, Ashish

doi:10.1007/s10601-008-9060-1

Cited by 22 publications

(15 citation statements)

References 48 publications

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“…In the activity example, the start and end variables can trigger the use of efficient scheduling-specific algorithms such as edge-finding (Carlier and Pinson 1990). In SymChaff (Sabharwal 2005(Sabharwal , 2009, a SAT solver especially designed to efficiently handle symmetries, high-level descriptions of AI planning problems written in a Planning Domain Description Language (PDDL) can be annotated with special tags to indicate which variables (or variable groups) are symmetric or interchangeable. These symmetries are then used by the solver to improve branching decisions, enable symmetric learning, and reduce the search space.…”

Section: Related Workmentioning

confidence: 99%

Modeling with Metaconstraints and Semantic Typing of Variables

Ciré

Hooker

Yunes³

2016

INFORMS Journal on Computing

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How to cite TSpace items Always cite the published version, so the author(s) will receive recognition through services that track citation counts, e.g. Scopus. If you need to cite the page number of the author manuscript from TSpace because you cannot access the published version, then cite the TSpace version in addition to the published version using the permanent URI (handle) found on the record page. This article was made openly accessible by U of T Faculty. Please tell us how this access benefits you. Your story matters.

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Section: Related Workmentioning

confidence: 99%

Modeling with Metaconstraints and Semantic Typing of Variables

Ciré

Hooker

Yunes³

2016

INFORMS Journal on Computing

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“…They intervene directly during the search exploration. It concerns, to mention but a few, the injection of symmetric versions of learned clauses [7,21], particular classes of symmetries [20], or speeding up the search by inferring symmetric facts [9]. These approaches succeeded in treating particular and hand crafted problems but, to the best of our knowledge, none of them is competitive face to the static symmetry breaking methods.…”

Section: Introductionmentioning

confidence: 99%

CDCLSym: Introducing Effective Symmetry Breaking in SAT Solving

Metin¹,

Baarir

Colange

et al. 2018

Lecture Notes in Computer Science

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Abstract. SAT solvers are now widely used to solve a large variety of problems, including formal verification of systems. SAT problems derived from such applications often exhibit symmetry properties that could be exploited to speed up their solving. Static symmetry breaking is so far the most popular approach to take advantage of symmetries. It relies on a symmetry preprocessor which augments the initial problem with constraints that force the solver to consider only a few configurations among the many symmetric ones. This paper presents a new way to handle symmetries, that avoid the main problem of the current static approaches: the prohibitive cost of the preprocessing phase. Our proposal has been implemented in MiniSym. Extensive experiments on the benchmarks of last six SAT competitions show that our approach is competitive with the best state-of-the-art static symmetry breaking solutions.

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“…The main conceptual novelty of our approach w.r.t the decision procedure, independent of the particular problem, is the pivotal role of the decision strategy. While custom SAT decision heuristics have been applied previously [3,24], our decision strategy replaces constraints, that is, it guarantees that the algorithm is sound even after we remove the heaviest part of the constraints used in our initial reduction to BV logic. In addition, we use the decision strategy rather than constraints for heuristically optimizing the solution (w.r.t track utilization).…”

Section: Introductionmentioning

confidence: 99%

Finding Bounded Path in Graph Using SMT for Automatic Clock Routing

Erez¹,

Nadel²

2015

Computer Aided Verification

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Automating the routing process is essential for the semiconductor industry to reduce time-to-market and increase productivity. This study sprang from the need to automate the following critical task in clock routing: given a set of nets, each net consisting of a driver and a receiver, connect each driver to its receiver, where the delay should be almost the same across the nets. We demonstrate that this problem can be reduced to bounded-path, that is, the NP-hard problem of finding a simple path, whose cost is bounded by a given range, connecting two given vertices in an undirected positively weighted graph. Furthermore, we show that bounded-path can be reduced to bit-vector reasoning and solved with a SAT-based bit-vector SMT solver. In order to render our solution scalable, we override the SAT solver's decision strategy with a novel graph-aware strategy and augment conflict analysis with a graphaware procedure. Our solution scales to graphs having millions of edges and vertices. It has been deployed at Intel for clock routing automation.

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SymChaff: exploiting symmetry in a structure-aware satisfiability solver

Cited by 22 publications

References 48 publications

Modeling with Metaconstraints and Semantic Typing of Variables

Modeling with Metaconstraints and Semantic Typing of Variables

CDCLSym: Introducing Effective Symmetry Breaking in SAT Solving

Finding Bounded Path in Graph Using SMT for Automatic Clock Routing

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