org.sosy_lab.cpachecker.pcc.strategy.partitioning.ExplorationOrderBalancedGraphPartitioner.java Source code

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Here is the source code for org.sosy_lab.cpachecker.pcc.strategy.partitioning.ExplorationOrderBalancedGraphPartitioner.java

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/*
 *  CPAchecker is a tool for configurable software verification.
 *  This file is part of CPAchecker.
 *
 *  Copyright (C) 2007-2014  Dirk Beyer
 *  All rights reserved.
 *
 *  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.
 *
 *
 *  CPAchecker web page:
 *    http://cpachecker.sosy-lab.org
 */
package org.sosy_lab.cpachecker.pcc.strategy.partitioning;

import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.Deque;
import java.util.List;
import java.util.Set;

import org.sosy_lab.cpachecker.core.ShutdownNotifier;
import org.sosy_lab.cpachecker.core.interfaces.pcc.BalancedGraphPartitioner;
import org.sosy_lab.cpachecker.pcc.strategy.partialcertificate.PartialReachedSetDirectedGraph;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.Sets;

public class ExplorationOrderBalancedGraphPartitioner implements BalancedGraphPartitioner {

    private final ShutdownNotifier shutdownNotifier;
    private final boolean useDFS;

    public ExplorationOrderBalancedGraphPartitioner(final boolean pDFS, final ShutdownNotifier pShutdownNotifier) {
        useDFS = pDFS;
        shutdownNotifier = pShutdownNotifier;
    }

    @Override
    public List<Set<Integer>> computePartitioning(int pNumPartitions, PartialReachedSetDirectedGraph pGraph)
            throws InterruptedException {
        Deque<Integer> waitlist = new ArrayDeque<>();
        BitSet inPartition = new BitSet(pGraph.getNumNodes());
        int partitionSize = pGraph.getNumNodes() / pNumPartitions + 1;

        List<Set<Integer>> result = new ArrayList<>(pNumPartitions);
        for (int i = 0; i < pNumPartitions; i++) {
            result.add(Sets.<Integer>newHashSetWithExpectedSize(partitionSize));
        }

        waitlist.add(0);
        inPartition.set(0);

        Integer next;
        int partition = 0;
        ImmutableList<ImmutableList<Integer>> adjacencyList = pGraph.getAdjacencyList();
        while (!waitlist.isEmpty()) {
            shutdownNotifier.shutdownIfNecessary();

            next = waitlist.poll();
            if (result.get(partition).size() > partitionSize) {
                partition++;
            }
            result.get(partition).add(next);

            for (Integer successor : adjacencyList.get(next)) {
                if (!inPartition.get(successor)) {
                    inPartition.set(successor);
                    if (useDFS) {
                        waitlist.push(successor);
                    } else {
                        waitlist.offer(successor);
                    }
                }
            }
        }

        return result;
    }

}