PhD graduated
Team : MoVe
Departure date : 07/04/2019

Supervision : Fabrice KORDON

Co-supervision : BAARIR Souheib, KORDON Fabrice, SOPENA Julien

Towards more efficient parallel SAT solving

Boolean SATisfiability has been used successfully in many applicative contexts. This is due to the capability of modern SAT solvers to solve complex problems involving millions of variables. Most SAT solvers have long been sequential and based on the CDCL algorithm. The emergence of many-core machines opens new possibilities in this domain.
There are numerous parallel SAT solvers that differ by their strategies, programming languages, etc. Hence, comparing the efficiency of the theoretical approaches in a fair way is a challenging task. Moreover, the introduction of a new approach needs a deep understanding of the existing solvers' implementations.
We present Painless: a framework to build parallel SAT solvers for many-core environments. Thanks to its genericness and modularity, it provides the implementation of basics for parallel SAT solving. It also enables users to easily create their parallel solvers based on new strategies.
Painless allowed to build and test existing strategies by using different chunk of solutions present in the literature. We were able to easily mimic the behaviour of three state-of-the-art solvers by factorising many parts of their implementations. The efficiency of Painless was highlighted as these implementations are at least efficient as the original ones. Moreover, one of our solvers won the SAT Competition'18.
Going further, Painless enabled to conduct fair experiments in the context of divide-and-conquer solvers, and allowed us to highlight original compositions of strategies performing better than already known ones. Also, we were able to create and test new original strategies exploiting the modular structure of SAT instances.

Defence : 07/03/2019 - 14h - EPITA, 14-16 rue Voltaire, salle KB604, 94270 Le Kremlin-BicĂŞtre

Jury members :

Michaël KRAJECKI, Professeur à l'Université de Reims, CReSTIC [Rapporteur]
Laurent SIMON, Professeur à l'Université de Bordeaux, LaBRI, CNRS [Rapporteur]
Daniel LE BERRE, Professeur à l'Université d'Artois, CRIL, CNRS
Bertrand LE CUN, Ingénieur Senior à Google Inc.
Clémence MAGNIEN, Directeur de Recherche au CNRS, LIP6, CNRS
Souheib BAARIR, Maître de Conférence à l'Université Paris Nanterre, LIP6, CNRS
Fabrice KORDON, Professeur à Sorbonne Université, LIP6, CNRS
Julien SOPENA, Maître de Conférence à Sorbonne Université, LIP6, CNRS, INRIA

2017-2020 Publications