org.logicng.cardinalityconstraints.CCAMOLadder 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. //
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// http://www.apache.org/licenses/LICENSE-2.0 //
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/*
* Open-WBO -- Copyright (c) 2013-2015, Ruben Martins, Vasco Manquinho, Ines Lynce
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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package org.logicng.cardinalityconstraints;
import org.logicng.datastructures.EncodingResult;
import org.logicng.formulas.Variable;
/**
* Encodes that at most one variable is assigned value true. Uses the Ladder/Regular encoding.
* @version 2.0.0
* @since 1.0
*/
public final class CCAMOLadder implements CCAtMostOne {
/**
* Constructs the naive AMO encoder.
*/
CCAMOLadder() {
}
@Override
public void build(final EncodingResult result, final Variable... vars) {
result.reset();
final Variable[] seqAuxiliary = new Variable[vars.length - 1];
for (int i = 0; i < vars.length - 1; i++) {
seqAuxiliary[i] = result.newVariable();
}
for (int i = 0; i < vars.length; i++) {
if (i == 0) {
result.addClause(vars[0].negate(), seqAuxiliary[0]);
} else if (i == vars.length - 1) {
result.addClause(vars[i].negate(), seqAuxiliary[i - 1].negate());
} else {
result.addClause(vars[i].negate(), seqAuxiliary[i]);
result.addClause(seqAuxiliary[i - 1].negate(), seqAuxiliary[i]);
result.addClause(vars[i].negate(), seqAuxiliary[i - 1].negate());
}
}
}
@Override
public String toString() {
return this.getClass().getSimpleName();
}
}