com.sri.ai.grinder.sgdpllt.theory.propositional.ModelCountingOfSingleVariablePropositionalConstraintStepSolver Maven / Gradle / Ivy
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package com.sri.ai.grinder.sgdpllt.theory.propositional;
import static com.sri.ai.expresso.helper.Expressions.ONE;
import static com.sri.ai.expresso.helper.Expressions.TWO;
import com.google.common.annotations.Beta;
import com.sri.ai.expresso.api.Expression;
import com.sri.ai.grinder.sgdpllt.api.Context;
import com.sri.ai.grinder.sgdpllt.core.solver.AbstractModelCountingWithPropagatedLiteralsImportedFromSatisfiabilityStepSolver;
/**
* A {@link AbstractModelCountingWithPropagatedLiteralsImportedFromSatisfiabilityStepSolver} for
* a {@link SingleVariablePropositionalConstraint}.
* As such, it is required to provide a way of computing a solution when all propagated literals and propagated CNF are satisfied by the context.
*
* if the propagated literals and propagated CNF are defined by the context, then a solution is already defined.
* The solution is simply 1 if the variable is constrained to be true or false, or 2 otherwise.
*
* @author braz
*
*/
@Beta
public class ModelCountingOfSingleVariablePropositionalConstraintStepSolver extends AbstractModelCountingWithPropagatedLiteralsImportedFromSatisfiabilityStepSolver {
public ModelCountingOfSingleVariablePropositionalConstraintStepSolver(SingleVariablePropositionalConstraint constraint) {
super(constraint);
}
@Override
public SingleVariablePropositionalConstraint getConstraint() {
return (SingleVariablePropositionalConstraint) super.getConstraint();
}
@Override
protected Step solutionIfPropagatedLiteralsAndSplittersCNFAreSatisfied(
Context context) {
boolean variableIsNotConstrained =
getConstraint().getPositiveNormalizedAtoms().isEmpty() && getConstraint().getNegativeNormalizedAtoms().isEmpty();
Expression solutionExpression = variableIsNotConstrained? TWO : ONE;
return new Solution(solutionExpression);
}
}