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Public API implementations for MinimumEdgeCutST
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jgalgo-core/src/main/java/com/jgalgo/alg/connect/MinimumEdgeCutSTAbstract.java
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| /*- | ||
| * Copyright 2023 Barak Ugav | ||
| * | ||
| * 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 com.jgalgo.alg.connect; | ||
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| import java.util.Collection; | ||
| import com.jgalgo.alg.IVertexBiPartition; | ||
| import com.jgalgo.alg.VertexBiPartition; | ||
| import com.jgalgo.graph.Graph; | ||
| import com.jgalgo.graph.IWeightFunction; | ||
| import com.jgalgo.graph.IndexGraph; | ||
| import com.jgalgo.graph.IndexIdMap; | ||
| import com.jgalgo.graph.IndexIdMaps; | ||
| import com.jgalgo.graph.WeightFunction; | ||
| import com.jgalgo.graph.WeightFunctions; | ||
| import com.jgalgo.internal.util.IntAdapters; | ||
| import it.unimi.dsi.fastutil.ints.IntCollection; | ||
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| /** | ||
| * Abstract class for computing the minimum edge cut between two vertices in a graph. | ||
| * | ||
| * <p> | ||
| * The class implements the interface by solving the problem on the index graph and then maps the results back to the | ||
| * original graph. The implementation for the index graph is abstract and left to the subclasses. | ||
| * | ||
| * @author Barak Ugav | ||
| */ | ||
| public abstract class MinimumEdgeCutSTAbstract implements MinimumEdgeCutST { | ||
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| /** | ||
| * Default constructor. | ||
| */ | ||
| public MinimumEdgeCutSTAbstract() {} | ||
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| @SuppressWarnings("unchecked") | ||
| @Override | ||
| public <V, E> VertexBiPartition<V, E> computeMinimumCut(Graph<V, E> g, WeightFunction<E> w, V source, V sink) { | ||
| if (g instanceof IndexGraph) { | ||
| IWeightFunction w0 = WeightFunctions.asIntGraphWeightFunc((WeightFunction<Integer>) w); | ||
| int source0 = ((Integer) source).intValue(), sink0 = ((Integer) sink).intValue(); | ||
| return (VertexBiPartition<V, E>) computeMinimumCut((IndexGraph) g, w0, source0, sink0); | ||
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| } else { | ||
| IndexGraph iGraph = g.indexGraph(); | ||
| IndexIdMap<V> viMap = g.indexGraphVerticesMap(); | ||
| IndexIdMap<E> eiMap = g.indexGraphEdgesMap(); | ||
| IWeightFunction iw = IndexIdMaps.idToIndexWeightFunc(w, eiMap); | ||
| int iSource = viMap.idToIndex(source); | ||
| int iSink = viMap.idToIndex(sink); | ||
| IVertexBiPartition indexCut = computeMinimumCut(iGraph, iw, iSource, iSink); | ||
| return VertexBiPartition.partitionFromIndexPartition(g, indexCut); | ||
| } | ||
| } | ||
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| @SuppressWarnings("unchecked") | ||
| @Override | ||
| public <V, E> VertexBiPartition<V, E> computeMinimumCut(Graph<V, E> g, WeightFunction<E> w, Collection<V> sources, | ||
| Collection<V> sinks) { | ||
| if (g instanceof IndexGraph) { | ||
| IWeightFunction w0 = WeightFunctions.asIntGraphWeightFunc((WeightFunction<Integer>) w); | ||
| IntCollection sources0 = IntAdapters.asIntCollection((Collection<Integer>) sources); | ||
| IntCollection sinks0 = IntAdapters.asIntCollection((Collection<Integer>) sinks); | ||
| return (VertexBiPartition<V, E>) computeMinimumCut((IndexGraph) g, w0, sources0, sinks0); | ||
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| } else { | ||
| IndexGraph iGraph = g.indexGraph(); | ||
| IndexIdMap<V> viMap = g.indexGraphVerticesMap(); | ||
| IndexIdMap<E> eiMap = g.indexGraphEdgesMap(); | ||
| IWeightFunction iw = IndexIdMaps.idToIndexWeightFunc(w, eiMap); | ||
| IntCollection iSources = IndexIdMaps.idToIndexCollection(sources, viMap); | ||
| IntCollection iSinks = IndexIdMaps.idToIndexCollection(sinks, viMap); | ||
| IVertexBiPartition indexCut = computeMinimumCut(iGraph, iw, iSources, iSinks); | ||
| return VertexBiPartition.partitionFromIndexPartition(g, indexCut); | ||
| } | ||
| } | ||
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| /** | ||
| * Compute the minimum edge-cut in a graph between two terminal vertices. | ||
| * | ||
| * @see #computeMinimumCut(Graph, WeightFunction, Object, Object) | ||
| * @param g a graph | ||
| * @param w an edge weight function | ||
| * @param source a special vertex that will be in \(C\) | ||
| * @param sink a special vertex that will be in \(\bar{C}\) | ||
| * @return the cut that was computed | ||
| */ | ||
| protected abstract IVertexBiPartition computeMinimumCut(IndexGraph g, IWeightFunction w, int source, int sink); | ||
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| /** | ||
| * Compute the minimum edge-cut in a graph between two sets of vertices. | ||
| * | ||
| * @see #computeMinimumCut(Graph, WeightFunction, Collection, Collection) | ||
| * @param g a graph | ||
| * @param w an edge weight function | ||
| * @param sources special vertices that will be in \(C\) | ||
| * @param sinks special vertices that will be in \(\bar{C}\) | ||
| * @return the minimum cut between the two sets | ||
| */ | ||
| protected abstract IVertexBiPartition computeMinimumCut(IndexGraph g, IWeightFunction w, IntCollection sources, | ||
| IntCollection sinks); | ||
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| } |
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