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This artifact provides the implementation of the L* learning algorithm described in the paper "Learning Regular
Sets from Queries and Counterexamples" (https://doi.org/10.1016/0890-5401(87)90052-6) by Dana Angluin including
variations and optimizations thereof such as the versions based on "On the Learnability of Infinitary Regular
Sets" (https://dx.doi.org/10.1006/inco.1995.1070) by Oded Maler and Amir Pnueli or "Inference of finite automata
using homing sequences" (http://dx.doi.org/10.1006/inco.1993.1021) by Ronald L. Rivest and Robert E. Schapire.
/* Copyright (C) 2013-2018 TU Dortmund
* This file is part of LearnLib, http://www.learnlib.de/.
*
* 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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package de.learnlib.algorithms.lstar.mealy;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import com.github.misberner.buildergen.annotations.GenerateBuilder;
import de.learnlib.algorithms.lstar.AbstractExtensibleAutomatonLStar;
import de.learnlib.algorithms.lstar.ce.ObservationTableCEXHandler;
import de.learnlib.algorithms.lstar.closing.ClosingStrategy;
import de.learnlib.api.oracle.MembershipOracle;
import de.learnlib.api.query.DefaultQuery;
import de.learnlib.datastructure.observationtable.OTLearner.OTLearnerMealy;
import de.learnlib.datastructure.observationtable.ObservationTable;
import de.learnlib.datastructure.observationtable.Row;
import net.automatalib.automata.concepts.SuffixOutput;
import net.automatalib.automata.transout.MealyMachine;
import net.automatalib.automata.transout.impl.compact.CompactMealy;
import net.automatalib.automata.transout.impl.compact.CompactMealyTransition;
import net.automatalib.words.Alphabet;
import net.automatalib.words.Word;
public class ExtensibleLStarMealy
extends AbstractExtensibleAutomatonLStar, I, Word, Integer, CompactMealyTransition, Void, O, CompactMealy>
implements OTLearnerMealy {
private final List outputTable = new ArrayList<>();
public ExtensibleLStarMealy(Alphabet alphabet,
MembershipOracle> oracle,
List> initialSuffixes,
ObservationTableCEXHandler super I, ? super Word> cexHandler,
ClosingStrategy super I, ? super Word> closingStrategy) {
this(alphabet, oracle, Collections.singletonList(Word.epsilon()), initialSuffixes, cexHandler, closingStrategy);
}
@GenerateBuilder(defaults = AbstractExtensibleAutomatonLStar.BuilderDefaults.class)
public ExtensibleLStarMealy(Alphabet alphabet,
MembershipOracle> oracle,
List> initialPrefixes,
List> initialSuffixes,
ObservationTableCEXHandler super I, ? super Word> cexHandler,
ClosingStrategy super I, ? super Word> closingStrategy) {
super(alphabet,
oracle,
new CompactMealy<>(alphabet),
initialPrefixes,
LStarMealyUtil.ensureSuffixCompliancy(initialSuffixes, alphabet, cexHandler.needsConsistencyCheck()),
cexHandler,
closingStrategy);
}
@Override
protected List> initialSuffixes() {
return initialSuffixes;
}
@Override
public CompactMealy getHypothesisModel() {
return internalHyp;
}
@Override
protected MealyMachine, I, ?, O> exposeInternalHypothesis() {
return internalHyp;
}
@Override
protected void updateInternalHypothesis() {
updateOutputs();
super.updateInternalHypothesis();
}
@Override
protected Void stateProperty(ObservationTable> table, Row stateRow) {
return null;
}
@Override
protected O transitionProperty(ObservationTable> table, Row stateRow, int inputIdx) {
Row transRow = stateRow.getSuccessor(inputIdx);
return outputTable.get(transRow.getRowId() - 1);
}
protected void updateOutputs() {
int numOutputs = outputTable.size();
int numTransRows = table.numberOfRows() - 1;
int newOutputs = numTransRows - numOutputs;
if (newOutputs == 0) {
return;
}
List>> outputQueries = new ArrayList<>(numOutputs);
for (int i = numOutputs + 1; i <= numTransRows; i++) {
Row row = table.getRow(i);
Word rowPrefix = row.getLabel();
int prefixLen = rowPrefix.size();
outputQueries.add(new DefaultQuery<>(rowPrefix.prefix(prefixLen - 1), rowPrefix.suffix(1)));
}
oracle.processQueries(outputQueries);
for (int i = 0; i < newOutputs; i++) {
DefaultQuery> query = outputQueries.get(i);
O outSym = query.getOutput().getSymbol(0);
outputTable.add(outSym);
}
}
@Override
protected SuffixOutput> hypothesisOutput() {
return internalHyp;
}
}