A Non-CDCL SAT Solver with Early Conflict Detection: The Watched

Computer Science > Logic in Computer Science [Submitted on 25 Aug 2026] Title:A Non-CDCL SAT Solver with Early Conflict Detection: The Watched-Literal-Based CSFLOC Solver View PDFAbstract:CSFLOC is a non-CDCL SAT decision procedure based on counting subsumed full-length ordered clauses. The classical CSFLOC loop traverses the ordered space of full-length clauses by a monotone counter: if the current full-length clause is not subsumed by the input formula, its negation is a satisfying assignment; otherwise, a subsuming clause determines a counter jump. The main bottleneck is the repeated search for such a subsuming clause. This paper presents CSFLOC-WL, and its current implementation CSFLOC-WL3, in which this search is replaced by watched-literal prefix propagation over the negation of the current full-length clause represented by the counter. The central mechanism is early conflict detection: if propagation under a common prefix derives opposite unit consequences for the same variable, then the two reason clauses are resolved immediately and the resolvent is used as a new counter-jump cause. The resulting solver is not a CDCL solver: it has no CDCL decision tree, no restart policy, and no first-UIP backjumping loop. It remains a counter-guided full-length-clause-counting solver, but it imports the watched-literal data structure and reason clauses as engineering tools for discovering jumps. Experiments on selected UNSAT SATLIB instances compare CSFLOC-WL3 with CSFLOC21TU and CaDiCaL 3.0.0. The results are mixed: CSFLOC-WL3 is strong on several random 3-SAT instances near the random-3-SAT satisfiability threshold, whereas CSFLOC21TU remains faster on several structured cases, apparently because it contains a more mature cache mechanism that is not yet present in CSFLOC-WL3. Submission history From: EPTCS [view email] [via EPTCS proxy][v1] Tue, 25 Aug 2026 08:49:28 UTC (36 KB) References & Citations Loading... Bibliographic and Citation Tools Bibliographic Explorer (What is the Explorer?) Connected Papers (What is Connected Papers?) Litmaps (What is Litmaps?) scite Smart Citations (What are Smart Citations?) Code, Data and Media Associated with this Article alphaXiv (What is alphaXiv?) CatalyzeX Code Finder for Papers (What is CatalyzeX?) DagsHub (What is DagsHub?) Gotit.pub (What is GotitPub?) Hugging Face (What is Huggingface?) ScienceCast (What is ScienceCast?) Demos Recommenders and Search Tools Influence Flower (What are Influence Flowers?) CORE Recommender (What is CORE?) arXivLabs: experimental projects with community collaborators arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website. Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them. Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs.