On Dedicated CDCL Strategies for PB Solvers

Berre, Daniel Le; Wallon, Romain

doi:10.1007/978-3-030-80223-3_22

Cited by 1 publication

(1 citation statement)

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“…We remark that the stopping criteria presented in this section are designed towards improving the backjump level computed by the conflict analysis procedure. However, different criteria may also be considered for determining when to stop the analysis, such as the quality of the derived constraint (e.g., with different quality measures as introduced in [12]), or its propensity to generate short proofs (e.g., by ensuring to derive constraints having a low slack).…”

Section: Ending Conflict Analysismentioning

confidence: 99%

On Improving the Backjump Level in PB Solvers

Wallon

2021

Preprint

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Current PB solvers implement many techniques inspired by the CDCL architecture of modern SAT solvers, so as to benefit from its practical efficiency. However, they also need to deal with the fact that many of the properties leveraged by this architecture are no longer true when considering PB constraints. In this paper, we focus on one of these properties, namely the optimality of the so-called first unique implication point (1-UIP). While it is well known that learning the first assertive clause produced during conflict analysis ensures to perform the highest possible backjump in a SAT solver, we show that there is no such guarantee in the presence of PB constraints. We also introduce and evaluate different approaches designed to improve the backjump level identified during conflict analysis by allowing to continue the analysis after reaching the 1-UIP. Our experiments show that sub-optimal backjumps are fairly common in PB solvers, even though their impact on the solver is not clear.

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Section: Ending Conflict Analysismentioning

confidence: 99%