/**
* Copyright (c) 1999-2014, Ecole des Mines de Nantes
* All rights reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the Ecole des Mines de Nantes nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package solver.constraints;
import gnu.trove.list.TIntList;
import gnu.trove.list.array.TIntArrayList;
import solver.Solver;
import solver.constraints.nary.cnf.*;
import solver.variables.BoolVar;
import solver.variables.VF;
import util.tools.StringUtils;
/**
* A factory dedicated to SAT.
* <p/>
* <br/>
*
* @author Charles Prud'homme
* @since 15/07/13
*/
public class SatFactory {
private SatFactory() {
}
private static boolean buildOnLogicalOperator(LogOp logOp, Solver solver) {
PropSat sat = solver.getMinisat().getPropSat();
ILogical tree = LogicTreeToolBox.toCNF(logOp, solver);
if (solver.ONE.equals(tree)) {
return addTrue(solver.ZERO);
} else if (solver.ZERO.equals(tree)) {
return addTrue(solver.ONE);
} else {
ILogical[] clauses;
if (!tree.isLit() && ((LogOp) tree).is(LogOp.Operator.AND)) {
clauses = ((LogOp) tree).getChildren();
} else {
clauses = new ILogical[]{tree};
}
boolean ret = true;
// init internal structures
for (int i = 0; i < clauses.length; i++) {
ILogical clause = clauses[i];
if (clause.isLit()) {
BoolVar bv = (BoolVar) clause;
ret &= addTrue(bv);
} else {
LogOp n = (LogOp) clause;
BoolVar[] bvars = n.flattenBoolVar();
TIntList lits = new TIntArrayList(bvars.length);
for (int j = 0; j < bvars.length; j++) {
lits.add(sat.Literal(bvars[j]));
}
ret &= sat.addClause(lits);
}
}
return ret;
}
}
/**
* Ensures that the clauses defined in the Boolean logic formula TREE are satisfied.
*
* @param TREE the syntactic tree
* @param SOLVER solver is required, as the TREE can be declared without any variables
* @return true if the clause has been added to the clause store
*/
public static boolean addClauses(LogOp TREE, Solver SOLVER) {
return buildOnLogicalOperator(TREE, SOLVER);
}
/**
* Ensures that the clause defined by POSLITS and NEGLITS is satisfied.
*
* @param POSLITS positive literals
* @param NEGLITS negative literals
* @return true if the clause has been added to the clause store
*/
public static boolean addClauses(BoolVar[] POSLITS, BoolVar[] NEGLITS) {
Solver solver = POSLITS.length > 0 ? POSLITS[0].getSolver() : NEGLITS[0].getSolver();
PropSat sat = solver.getMinisat().getPropSat();
TIntList lits = new TIntArrayList(POSLITS.length + NEGLITS.length);
for (int i = 0; i < POSLITS.length; i++) {
lits.add(sat.Literal(POSLITS[i]));
}
for (int i = 0; i < NEGLITS.length; i++) {
lits.add(SatSolver.negated(sat.Literal(NEGLITS[i])));
}
sat.addClause(lits);
return true;
}
/**
* Add a unit clause stating that BOOLVAR must be true
*
* @param BOOLVAR a boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addTrue(BoolVar BOOLVAR) {
Solver solver = BOOLVAR.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int lit = sat.Literal(BOOLVAR);
sat.addClause(SatSolver.negated(lit));
return true;
}
/**
* Add a unit clause stating that BOOLVAR must be false
*
* @param BOOLVAR a boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addFalse(BoolVar BOOLVAR) {
Solver solver = BOOLVAR.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int lit = SatSolver.negated(sat.Literal(BOOLVAR));
sat.addClause(lit);
return true;
}
/**
* Add a clause stating that: LEFT == RIGHT
*
* @param LEFT a boolean variable
* @param RIGHT another boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolEq(BoolVar LEFT, BoolVar RIGHT) {
Solver solver = LEFT.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int left_lit = sat.Literal(LEFT);
int right_lit = sat.Literal(RIGHT);
sat.addClause(SatSolver.negated(left_lit), right_lit);
sat.addClause(left_lit, SatSolver.negated(right_lit));
return true;
}
/**
* Add a clause stating that: LEFT ≤ RIGHT
*
* @param LEFT a boolean variable
* @param RIGHT another boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolLe(BoolVar LEFT, BoolVar RIGHT) {
Solver solver = LEFT.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int left_lit = sat.Literal(LEFT);
int right_lit = sat.Literal(RIGHT);
sat.addClause(SatSolver.negated(left_lit), right_lit);
return true;
}
/**
* Add a clause stating that: LEFT < RIGHT
*
* @param LEFT a boolean variable
* @param RIGHT another boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolLt(BoolVar LEFT, BoolVar RIGHT) {
Solver solver = LEFT.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int left_lit = sat.Literal(LEFT);
int right_lit = sat.Literal(RIGHT);
sat.addClause(right_lit);
sat.addClause(SatSolver.negated(left_lit), SatSolver.negated(right_lit));
return true;
}
/**
* Add a clause stating that: LEFT != RIGHT
*
* @param LEFT a boolean variable
* @param RIGHT another boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolNot(BoolVar LEFT, BoolVar RIGHT) {
Solver solver = LEFT.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int left_lit = sat.Literal(LEFT);
int right_lit = sat.Literal(RIGHT);
sat.addClause(SatSolver.negated(left_lit), SatSolver.negated(right_lit));
sat.addClause(left_lit, right_lit);
return true;
}
/**
* Add a clause stating that: (BOOLVARS<sub>1</sub>∨BOOLVARS<sub>2</sub>∨...∨BOOLVARS<sub>n</sub>) ⇔ TARGET
*
* @param BOOLVARS a list of boolean variables
* @param TARGET the reified boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolOrArrayEqVar(BoolVar[] BOOLVARS, BoolVar TARGET) {
Solver solver = TARGET.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int target_lit = sat.Literal(TARGET);
TIntList lits = new TIntArrayList(BOOLVARS.length + 1);
for (int i = 0; i < BOOLVARS.length; i++) {
lits.add(sat.Literal(BOOLVARS[i]));
}
lits.add(SatSolver.negated(target_lit));
sat.addClause(lits);
for (int i = 0; i < BOOLVARS.length; i++) {
sat.addClause(target_lit, SatSolver.negated(sat.Literal(BOOLVARS[i])));
}
return true;
}
/**
* Add a clause stating that: (BOOLVARS<sub>1</sub>∧BOOLVARS<sub>2</sub>∧...∧BOOLVARS<sub>n</sub>) ⇔ TARGET
*
* @param BOOLVARS a list of boolean variables
* @param TARGET the reified boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolAndArrayEqVar(BoolVar[] BOOLVARS, BoolVar TARGET) {
Solver solver = TARGET.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int target_lit = sat.Literal(TARGET);
TIntList lits = new TIntArrayList(BOOLVARS.length + 1);
for (int i = 0; i < BOOLVARS.length; i++) {
lits.add(SatSolver.negated(sat.Literal(BOOLVARS[i])));
}
lits.add(target_lit);
sat.addClause(lits);
for (int i = 0; i < BOOLVARS.length; i++) {
sat.addClause(SatSolver.negated(target_lit), sat.Literal(BOOLVARS[i]));
}
return true;
}
/**
* Add a clause stating that: (LEFT ∨ RIGHT) ⇔ TARGET
*
* @param LEFT a boolean variable
* @param RIGHT another boolean variable
* @param TARGET the reified boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolOrEqVar(BoolVar LEFT, BoolVar RIGHT, BoolVar TARGET) {
Solver solver = TARGET.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int left_lit = sat.Literal(LEFT);
int right_lit = sat.Literal(RIGHT);
int target_lit = sat.Literal(TARGET);
sat.addClause(left_lit, right_lit, SatSolver.negated(target_lit));
sat.addClause(SatSolver.negated(left_lit), target_lit);
sat.addClause(SatSolver.negated(right_lit), target_lit);
return true;
}
/**
* Add a clause stating that: (LEFT ∧ RIGHT) ⇔ TARGET
*
* @param LEFT a boolean variable
* @param RIGHT another boolean variable
* @param TARGET the reified boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolAndEqVar(BoolVar LEFT, BoolVar RIGHT, BoolVar TARGET) {
Solver solver = TARGET.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int left_lit = sat.Literal(LEFT);
int right_lit = sat.Literal(RIGHT);
int target_lit = sat.Literal(TARGET);
sat.addClause(SatSolver.negated(left_lit), SatSolver.negated(right_lit), target_lit);
sat.addClause(left_lit, SatSolver.negated(target_lit));
sat.addClause(right_lit, SatSolver.negated(target_lit));
return true;
}
/**
* Add a clause stating that: (LEFT ⊕ RIGHT) ⇔ TARGET
*
* @param LEFT a boolean variable
* @param RIGHT another boolean variable
* @param TARGET the reified boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolXorEqVar(BoolVar LEFT, BoolVar RIGHT, BoolVar TARGET) {
return addBoolIsNeqVar(LEFT, RIGHT, TARGET);
}
/**
* Add a clause stating that: (LEFT == RIGHT) ⇔ TARGET
*
* @param LEFT a boolean variable
* @param RIGHT another boolean variable
* @param TARGET the reified boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolIsEqVar(BoolVar LEFT, BoolVar RIGHT, BoolVar TARGET) {
Solver solver = TARGET.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int left_lit = sat.Literal(LEFT);
int right_lit = sat.Literal(RIGHT);
int target_lit = sat.Literal(TARGET);
sat.addClause(SatSolver.negated(left_lit), right_lit, SatSolver.negated(target_lit));
sat.addClause(left_lit, SatSolver.negated(right_lit), SatSolver.negated(target_lit));
sat.addClause(left_lit, right_lit, target_lit);
sat.addClause(SatSolver.negated(left_lit), SatSolver.negated(right_lit), target_lit);
return true;
}
/**
* Add a clause stating that: (LEFT ≠ RIGHT) ⇔ TARGET
*
* @param LEFT a boolean variable
* @param RIGHT another boolean variable
* @param TARGET the reified boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolIsNeqVar(BoolVar LEFT, BoolVar RIGHT, BoolVar TARGET) {
Solver solver = TARGET.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int left_lit = sat.Literal(LEFT);
int right_lit = sat.Literal(RIGHT);
int target_lit = sat.Literal(TARGET);
sat.addClause(SatSolver.negated(left_lit), right_lit, target_lit);
sat.addClause(left_lit, SatSolver.negated(right_lit), target_lit);
sat.addClause(left_lit, right_lit, SatSolver.negated(target_lit));
sat.addClause(SatSolver.negated(left_lit), SatSolver.negated(right_lit), SatSolver.negated(target_lit));
return true;
}
/**
* Add a clause stating that: (LEFT ≤ RIGHT) ⇔ TARGET
*
* @param LEFT a boolean variable
* @param RIGHT another boolean variable
* @param TARGET the reified boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolIsLeVar(BoolVar LEFT, BoolVar RIGHT, BoolVar TARGET) {
Solver solver = TARGET.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int left_lit = sat.Literal(LEFT);
int right_lit = sat.Literal(RIGHT);
int target_lit = sat.Literal(TARGET);
sat.addClause(SatSolver.negated(left_lit), right_lit, SatSolver.negated(target_lit));
sat.addClause(left_lit, target_lit);
sat.addClause(SatSolver.negated(right_lit), target_lit);
return true;
}
/**
* Add a clause stating that: (LEFT < RIGHT) ⇔ TARGET
*
* @param LEFT a boolean variable
* @param RIGHT another boolean variable
* @param TARGET the reified boolean variable
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolIsLtVar(BoolVar LEFT, BoolVar RIGHT, BoolVar TARGET) {
Solver solver = TARGET.getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int left_lit = sat.Literal(LEFT);
int right_lit = sat.Literal(RIGHT);
int target_lit = sat.Literal(TARGET);
sat.addClause(left_lit, right_lit, SatSolver.negated(target_lit));
sat.addClause(SatSolver.negated(left_lit), right_lit, SatSolver.negated(target_lit));
sat.addClause(left_lit, SatSolver.negated(right_lit), target_lit);
sat.addClause(SatSolver.negated(left_lit), SatSolver.negated(right_lit), SatSolver.negated(target_lit));
return true;
}
/**
* Add a clause stating that: BOOLVARS<sub>1</sub>∨BOOLVARS<sub>2</sub>∨...∨BOOLVARS<sub>n</sub>
*
* @param BOOLVARS a list of boolean variables
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolOrArrayEqualTrue(BoolVar[] BOOLVARS) {
Solver solver = BOOLVARS[0].getSolver();
PropSat sat = solver.getMinisat().getPropSat();
TIntList lits = new TIntArrayList(BOOLVARS.length);
for (int i = 0; i < BOOLVARS.length; i++) {
lits.add(sat.Literal(BOOLVARS[i]));
}
sat.addClause(lits);
return true;
}
/**
* Add a clause stating that: BOOLVARS<sub>1</sub>∧BOOLVARS<sub>2</sub>∧...∧BOOLVARS<sub>n</sub>
*
* @param BOOLVARS a list of boolean variables
* @return true if the clause has been added to the clause store
*/
public static boolean addBoolAndArrayEqualFalse(BoolVar[] BOOLVARS) {
return addAtMostNMinusOne(BOOLVARS);
}
/**
* Add a clause stating that: ∑ BOOLVARS<sub>i</sub> ≤ 1
*
* @param BOOLVARS a list of boolean variables
* @return true if the clause has been added to the clause store
*/
public static boolean addAtMostOne(BoolVar[] BOOLVARS) {
Solver solver = BOOLVARS[0].getSolver();
PropSat sat = solver.getMinisat().getPropSat();
TIntList lits = new TIntArrayList(BOOLVARS.length);
for (int i = 0; i < BOOLVARS.length; i++) {
lits.add(SatSolver.negated(sat.Literal(BOOLVARS[i])));
}
for (int i = 0; i < lits.size() - 1; i++) {
for (int j = i + 1; j < lits.size(); ++j) {
sat.addClause(lits.get(i), lits.get(j));
}
}
return true;
}
/**
* Add a clause stating that: ∑ BOOLVARS<sub>i</sub> ≤ n-1
*
* @param BOOLVARS a list of boolean variables
* @return true if the clause has been added to the clause store
*/
public static boolean addAtMostNMinusOne(BoolVar[] BOOLVARS) {
Solver solver = BOOLVARS[0].getSolver();
PropSat sat = solver.getMinisat().getPropSat();
TIntList lits = new TIntArrayList(BOOLVARS.length);
for (int i = 0; i < BOOLVARS.length; i++) {
lits.add(SatSolver.negated(sat.Literal(BOOLVARS[i])));
}
sat.addClause(lits);
return true;
}
/**
* Add a clause stating that: sum(BOOLVARS<sub>i</sub>) ≥ TARGET
*
* @param BOOLVARS a list of boolean variables
* @return true if the clause has been added to the clause store
*/
public static boolean addSumBoolArrayGreaterEqVar(BoolVar[] BOOLVARS, BoolVar TARGET) {
Solver solver = BOOLVARS[0].getSolver();
PropSat sat = solver.getMinisat().getPropSat();
TIntList lits = new TIntArrayList(BOOLVARS.length + 1);
for (int i = 0; i < BOOLVARS.length; ++i) {
lits.add(sat.Literal(BOOLVARS[i]));
}
lits.add(SatSolver.negated(sat.Literal(TARGET)));
sat.addClause(lits);
return true;
}
/**
* Add a clause stating that: max(BOOLVARS<sub>i</sub>) ≤ TARGET
*
* @param BOOLVARS a list of boolean variables
* @return true if the clause has been added to the clause store
*/
public static boolean addMaxBoolArrayLessEqVar(BoolVar[] BOOLVARS, BoolVar TARGET) {
Solver solver = BOOLVARS[0].getSolver();
PropSat sat = solver.getMinisat().getPropSat();
int tlit = sat.Literal(TARGET);
for (int i = 0; i < BOOLVARS.length; ++i) {
sat.addClause(SatSolver.negated(sat.Literal(BOOLVARS[i])), tlit);
}
return true;
}
/**
* Add a clause stating that: sum(BOOLVARS<sub>i</sub>) ≤ TARGET
*
* @param BOOLVARS a list of boolean variables
* @return true if the clause has been added to the clause store
*/
public static boolean addSumBoolArrayLessEqVar(BoolVar[] BOOLVARS, BoolVar TARGET) {
Solver solver = BOOLVARS[0].getSolver();
PropSat sat = solver.getMinisat().getPropSat();
if (BOOLVARS.length == 1) {
return addBoolLe(BOOLVARS[0], TARGET);
}
BoolVar extra = VF.bool(StringUtils.randomName(), solver);
int tlit = sat.Literal(TARGET);
int elit = sat.Literal(extra);
TIntList lits = new TIntArrayList(BOOLVARS.length + 1);
for (int i = 0; i < BOOLVARS.length; ++i) {
lits.add(sat.Literal(BOOLVARS[i]));
}
lits.add(SatSolver.negated(elit));
sat.addClause(lits);
for (int i = 0; i < BOOLVARS.length; ++i) {
sat.addClause(elit, SatSolver.negated(sat.Literal(BOOLVARS[i])));
}
sat.addClause(SatSolver.negated(elit), tlit);
return true;
}
// public static boolean addArrayXor(PropSat sat, BoolVar[] vars) {
// return false;
// }
}