org.btrplace.scheduler.runner.disjoint.splitter.GatherSplitter Maven / Gradle / Ivy

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Instance solvers that split a single problem into smaller parts to solve them in parallel.

There is a newer version: 1.12.10

/*
 * Copyright (c) 2016 University Nice Sophia Antipolis
 *
 * This file is part of btrplace.
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see .
 */

package org.btrplace.scheduler.runner.disjoint.splitter;

import gnu.trove.map.hash.TIntIntHashMap;
import org.btrplace.model.Instance;
import org.btrplace.model.VM;
import org.btrplace.model.constraint.Gather;
import org.btrplace.scheduler.runner.disjoint.model.ElementSubSet;
import org.btrplace.scheduler.runner.disjoint.model.IterateProcedure;
import org.btrplace.scheduler.runner.disjoint.model.SplittableElementSet;

import java.util.List;

/**
 * Splitter for {@link org.btrplace.model.constraint.Gather} constraints.
 * 
 * When the constraint focuses VMs among different partitions,
 * then it is sure the problem has no solutions.
 *
 * @author Fabien Hermenier
 */
public class GatherSplitter implements ConstraintSplitter {

    @Override
    public Class getKey() {
        return Gather.class;
    }

    @Override
    public boolean split(Gather cstr, Instance origin, final List partitions, TIntIntHashMap vmsPosition, TIntIntHashMap nodePosition) {
        final boolean c = cstr.isContinuous();
        return SplittableElementSet.newVMIndex(cstr.getInvolvedVMs(), vmsPosition).
                forEachPartition(new IterateProcedure() {

                    private boolean first = true;

                    @Override
                    public boolean extract(SplittableElementSet index, int idx, int from, int to) {
                        if (!first) {
                            return false;
                        }
                        if (to - from >= 2) {
                            partitions.get(idx).getSatConstraints().add(new Gather(new ElementSubSet<>(index, idx, from, to), c));
                            first = false;
                        }
                        return true;
                    }
                });
    }
}