First solver in the Museum: GRASP

Fri, 30 Oct 2015 00:00:00 +0000

Joao Marques Silva provided to the museum the source code of the original GRASP back in 1996.

It is available in a specific git repository.

GRASP is important in the history of SAT because it is considered as the root of the Conflict Driven Clause Learning architecture: the authors of GRASP received the 2009 CAV Award to recognise that major contribution to the current efficiency of SAT solvers.

The solver was presented in the papers:

João P. Marques Silva, Karem A. Sakallah: GRASP: A Search Algorithm for Propositional Satisfiability. IEEE Trans. Computers 48(5): 506-521 (1999)
João P. Marques Silva, Karem A. Sakallah: GRASP - a new search algorithm for satisfiability. ICCAD 1996: 220-227
João P. Marques Silva, Karem A. Sakallah: Conflict Analysis in Search Algorithms for Satisfiability. ICTAI 1996: 467-469

Joao Marques Silva developed the main ideas behind GRASP during his PhD titled Search Algorithms for Satisfiability Problems in Combinational Switching Circuits, defended at the University of Michigan, Electrical Engineering and Computer Science department in 1995.

The solver is coded in C++ with a neat object oriented design. The main function solve, abstracted in all CDCL presentations, can be found in the GRASP_SAT class. Such class delegates to three different classes, BRE for Backward Reasoning Engine, DecisionEngine for the decision heuristics and FRE for Forward Reasoning Engine (aka Boolean Constraint Propagation).

The SAT Museum

First solver in the Museum: GRASP