net.automatalib.util.automata.ads.SplitTree Maven / Gradle / Ivy
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This artifact provides various common utility operations for analyzing and manipulating
automata and graphs, such as traversal, minimization and copying.
/* Copyright (C) 2013-2019 TU Dortmund
* This file is part of AutomataLib, http://www.automatalib.net/.
*
* 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 net.automatalib.util.automata.ads;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import net.automatalib.words.Word;
/**
* Utility class originally used by the algorithm of {@link LeeYannakakis} but utilized by other ADS computations as
* well.
*
* @param
* (hypothesis) state type
* @param
* input alphabet type
* @param
* output alphabet type
*
* @author frohme
*/
class SplitTree {
private final Map> successors;
private final Map mapping;
private final Set partition;
private Word sequence;
SplitTree(final Set partition) {
this.partition = partition;
this.successors = new HashMap<>();
this.mapping = new HashMap<>();
this.sequence = Word.epsilon();
}
public Map> getSuccessors() {
return successors;
}
public Map getMapping() {
return mapping;
}
public Set getPartition() {
return partition;
}
public Word getSequence() {
return sequence;
}
public void setSequence(Word sequence) {
this.sequence = sequence;
}
public Optional> findLowestSubsetNode(final Set nodes) {
for (final SplitTree st : successors.values()) {
final Optional> candidate = st.findLowestSubsetNode(nodes);
if (candidate.isPresent()) {
return candidate;
}
}
if (this.partition.containsAll(nodes)) {
return Optional.of(this);
}
return Optional.empty();
}
@Override
public String toString() {
return String.format("[states: %s, seq=%s]", this.partition.toString(), this.sequence.toString());
}
}