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Unformatted text preview: FLAC Project — Using SAT to Solve Sudoku Although SAT is an NP-complete problem in general, certain kinds of large SAT instances can be solved in a reasonable amount of time. In this project, you will use a SAT solver to solve Sudoku puzzles. Most existing SAT solvers require the input formula to be in Conjunctive Normal Form (CNF). The most commonly used input for- mat is the DIMACS format, whose structure is as shown at the right: p cnf NumVars NumClauses Clause 1 Clause 2 . . . Clause n The variables are assumed to be numbered from 1 to NumVars . The i th variable is repre- sented by the positive integer i ; the negation of this variable is represented by the negative integer- i . A clause is represented by listing the literals in the clause, separated by spaces, followed by a zero (“ ”). For example, the be- low CNF formula is represented in DIMACS as shown at the right. p cnf 4 5 1 0 2 -3 0-4 -1 0-1 -2 3 4 0-2 4 0 x 1 ∧ ( x 2 ∨ ¬ x 3 ) ∧ ( ¬ x 4 ∨ ¬ x 1 ) ∧ ( ¬ x 1 ∨ ¬ x 2 ∨ x 3 ∨ x 4 ) ∧ ( ¬ x 2 ∨ x 4 ) For more information about DIMACS, see: http://www.cs.ubc.ca/~hoos/SATLIB/Benchmarks/SAT/satformat.pshttp://www....
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This note was uploaded on 02/29/2012 for the course CS 15-453 taught by Professor Edmundm.clarke during the Spring '09 term at Carnegie Mellon.
- Spring '09