SAT2002 competition news
Last modifications: September 11, 2002
Check out the competition report here: HTML, PS, PDF.
More news concerning March solvers:
The heuristics used in the March solvers can be found in the paper:
Solving satisfiability problems using elliptic approximations: effective branching rules by
Joost Warners and Hans van Maaren
(Discrete Applied Mathematics 107 (2000), 241-259)
Award summary
More detailed infos coming soon!!!!!
Best performance of a complete solver on industrial benchmarks
ZCHAFF, from Lintao Zhang and Sharad Malik
Description:
M.W. Moskewicz, C.F. Madigan, Y. Zhao, L. Zhang, and S. Malik, Chaff:
Engineering an Efficient SAT Solver, 38th Design Automation Conference
(DAC'01), June 2001, pp. 530-535.
L. Zhang,
C.F. Madigan, M.W. Moskewicz, and S. Malik, Efficient Conflict Driven
Learning in a Boolean Satisfiability Solver, International Conference
on Computer-Aided Design (ICCAD '01), November 2001, pp. 279-285.
Best performance of a solver on satisfiable industrial benchmarks
LIMMAT, from Armin Biere
Description:
No paper available. Quoted from the author:
zchaff-like SAT solver with:
- early detection of conflicts in the BCP queue
- constant time lookup of the 'other' watched literal
- optimized ordering of decision variables
- implemented in C 5. robust code through sophisticated test framework
Get Limmat source code here
Best performance of a complete solver on handmade benchmarks
ZCHAFF, from Lintao Zhang and Sharad Malik
Description: as above
Best performance of a solver on satisfiable handmade benchmarks
BERKMIN, from Eugene Goldberg and Yakov Novikov
Description:
E. Goldberg, and Y. Novikov, BerkMin: A Fast and Robust
Sat-Solver, Design, Automation, and Test in Europe (DATE '02), March
2002, pp. 142-149.
Best performance of a complete solver on random benchmarks
OKSOLVER, from Oliver Kullmann
Description:
Heuristics for SAT algorithms: Searching for some
foundations. September 1998, 23 pages. (Updated September 1999 w.r.t.
running times.)
Best performance of a solver on satisfiable random benchmarks
OKSOLVER, from Oliver Kullmann
Description: as above.
Smallest unsolved unsatisfiable instance:
xor-chains, from Lintao Zhang and Sharad Malik
Description: 106 variables, 282 clauses, 844 literals, Verification
problem of 2 xor chains
Smallest unsolved satisfiable instance:
generated from hgen-2, from Edward A. Hirsch
Description: 500 variables, 1750 clauses, 5250 literals randomly
generated 3-CNF, clause/variables ratio=3.5
- balanced number of literal occurrences (no literal occurs much
more frequently than others)
- literals forcing the satisfying assignment are less frequent
- Formula does not contain clauses C_1, C_2, C_3 such that
C_1 contains variables a,b;
C_2 contains variables b,c;
C_3 contains variables a,c.
First stage results
We are now ready to
unveil the first stage results.
Some solvers reported UNSAT on SAT instances: we decided to put them
hors-concours, which means that they won't go to the next stage,
and that we will not consider their results for the awards.
Here is the list of those solvers:
- lsat
- MarchI, MarchIse
- partsat
- sato
Note that most of the time these solvers worked fine and that their unexpected
behavior is localized to a few families of benchmarks only.
One solver gave wrong SAT certificates for some instances. We decided
to consider these instances as unsolved.
List of submitted benchmarks
Here
is the list of submitted benchmarks.
Benchmarks submission
We have 901 generated benchmarks (with automatically submitted satex
challenging instances and 2 sub-families from Miroslav Velev's BMC) in 41
groups.
11 different random-generators (all looking "more or less" like 'k-SAT
uniform' generators, some force the instance to be satisfiable).
We have two others non-random generators in addition.
Solvers submission
19 author groups submitted 30 solvers: 28 were accepted for the competition
in which 3 are 'hors-concours'*, 2 solvers were rejected after the test
phase.
Among the 28 solvers:
- 17 complete deterministic solvers
- 11 randomized solvers
in which 8 solvers are incomplete.
The solvers are written in C/C++, except one in JAVA.
* The 3 solvers running 'hors-concours' have been modified after the
bug-testing stage by their authors while were not found buggy by the competition
organizing committee.
List of competing solvers (no particular order)
Armin BIERE limmat (compl. det.)
Steven PRESTWICH saturn (incompl. rand.)
Fahiem BACCHUS 2clseq (compl. det.)
Marijn HEULE (Hans vanMAAREN, Mark DUFOUR, Joris vanZWIETEN) marchI,marchIse,marchII,marchIIse (compl. det.)
Anatoly PLOTNIKOV (Stas BUSYGIN) blindsat (compl. det.)
Anton EREMEEV (Pavel BORISOVSKY) ga (incomp. rand.)
Eugene GOLDBERG (Yakov NOVIKOV) berkmin (comp. det.)
Edward HIRSCH (Arist KOJEVNIKOV) unitwalk (incomp. rand.)
Joao MARQUES-SILVA (Inês LYNCE) jquest (comp. rand)
Richard OSTROWSKI (Bertrand MAZURE, Lakhdar SAIS) lsat (comp. det.)
Bu DONGBO usat05,usat10 (incomp. rand.)
Hantao ZHANG sato (comp. rand.)
Armando TACCHELLA (Enrico GIUNCHIGLIA, Massimo MARATEA) simo (comp. rand.)
Oliver KULLMANN oksolver (comp. det.)
Benjamin WAH (Alan ZHE WU) dlmsat1,dlmsat2,dlmsat3 (incomp. rand.)
Allen VANGELDER rb2cl,modoc (comp. det.)
Lintao ZHANG (Sharad MALIK) chaff (comp. det.)
John KOLEN partsat (comp. det.)
Hors-concours:
Marijn HEULE (Hans vanMAAREN, Mark DUFOUR, Joris vanZWIETEN),marchIse-hc,marchII-hc,marchIIse-hc (compl. det.)
The competition
The competition started April 8, 2002 on a cluster of 30 Bi-Pentium III
(and not II as previously stated) 450 Mhz with 1Gb of RAM under Linux. Only
one processor is used for running the competition.
Each solver is given 40 minutes and 900Mb to solve an instance.
As soon as we have first results to be published, we'll made them available
on the web (using satex publishing framework).
http://www.lri.fr/~simon/satex/competition
The organizing committee
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