partitionStrategy.h

/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2015 Yichao Cheng
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */


/**
 * Strategies for partitioning graph.
 *
 * Author: Yichao Cheng (onesuperclark@gmail.com)
 * Created on: 2014-11-04
 * Last Modified: 2014-11-04
 */

#ifndef PARTITION_STRATEGY_H
#define PARTITION_STRATEGY_H

#include "common.h"
#include "utils.h"

/**
 * An interface for partitioning vertices for flexible graph representation.
 *
 * TODO(onesuper): Partitioning according to the topology of graph.
 * A partition strategy may possibly consider some of the graph attributes,
 * e.g. out-degree, etc.
 */
class PartitionStrategy {
public:
    /**
     * Returns the partition number for a given vertex.
     * @param  id        Id for the vertex in graph
     * @param  numParts  Number of parts to partition
     * @return           The partition number for a given vertex
     */
    virtual PartitionId getPartition(VertexId id, PartitionId numParts) const = 0;
};

class RandomEdgeCut: public PartitionStrategy {
    PartitionId getPartition(VertexId id, PartitionId numParts) const {
        return util::hashCode(id) % numParts;
    }
};


#endif  // PARTION_STRATEGY_H