org.logicng.transformations.cnf.BDDCNFTransformation Maven / Gradle / Ivy
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// The Next Generation Logic Library //
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// Copyright 2015-20xx Christoph Zengler //
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// Licensed under the Apache License, Version 2.0 (the "License"); //
// you may not use this file except in compliance with the License. //
// You may obtain a copy of the License at //
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// http://www.apache.org/licenses/LICENSE-2.0 //
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// Unless required by applicable law or agreed to in writing, software //
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package org.logicng.transformations.cnf;
import org.logicng.formulas.Formula;
import org.logicng.formulas.FormulaFactory;
import org.logicng.knowledgecompilation.bdds.jbuddy.BDDKernel;
import org.logicng.transformations.BDDNormalFormTransformation;
/**
* Transformation of a formula in CNF by converting it to a BDD.
* @version 2.3.0
* @since 1.4.0
*/
public final class BDDCNFTransformation extends BDDNormalFormTransformation {
/**
* Constructs a new BDD-based CNF transformation with an optional BDD kernel.
*
* Warning: You can use this object for arbitrarily many transformations, but
* the number of different variables in all applied formulas must not exceed
* the number of variables in the kernel.
* @param kernel the optional BDD kernel
*/
public BDDCNFTransformation(final BDDKernel kernel) {
super(kernel);
}
/**
* Constructs a new BDD-based CNF transformation for a given number of variables.
*
* Warning: You can use this object for arbitrarily many transformations, but
* the number of different variables in all applied formulas must not exceed
* {@code numVars}.
*
* To improve performance you might want to use {@link #BDDCNFTransformation(BDDKernel)},
* where you have full control over the node and cache size in the used BDD kernel.
* @param f the formula factory to use
* @param numVars the number of variables
*/
public BDDCNFTransformation(final FormulaFactory f, final int numVars) {
super(f, numVars);
}
/**
* Constructs a new BDD-based CNF transformation and constructs a new BDD kernel
* for every formula application.
*/
public BDDCNFTransformation() {
this(null);
}
@Override
public Formula apply(final Formula formula, final boolean cache) {
return compute(formula, true, cache);
}
}