org.apache.ignite.ml.genetic.CrossOverTask Maven / Gradle / Ivy

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.ignite.ml.genetic;

import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.ignite.Ignite;
import org.apache.ignite.IgniteException;
import org.apache.ignite.cache.affinity.Affinity;
import org.apache.ignite.cluster.ClusterNode;
import org.apache.ignite.compute.ComputeJob;
import org.apache.ignite.compute.ComputeJobResult;
import org.apache.ignite.compute.ComputeJobResultPolicy;
import org.apache.ignite.compute.ComputeTaskAdapter;
import org.apache.ignite.resources.IgniteInstanceResource;

import org.apache.ignite.ml.genetic.parameter.GAConfiguration;
import org.apache.ignite.ml.genetic.parameter.GAGridConstants;

/**
 * Responsible for assigning 2 X 'parent' chromosomes to produce 2 X 'child' chromosomes.
 *
 * 
 *
 * CrossOverTask leverages  Ignite's data affinity capabilities for routing CrossOverJobs to primary 
 IgniteNode
 * where 'parent' chromosomes reside.
 *
 * 
 */
public class CrossOverTask extends ComputeTaskAdapter, Boolean> {
    /** Ignite instance */
    @IgniteInstanceResource
    private Ignite ignite = null;

    /** GAConfiguration */
    private GAConfiguration config = null;

    /**
     * @param config GAConfiguration
     */
    public CrossOverTask(GAConfiguration config) {
        this.config = config;
    }

    /**
     * Map Jobs to nodes using data affinity.
     *
     * @param nodes Cluster Nodes
     * @param chromosomeKeys Primary keys for respective chromosomes
     * @return A map of nodes to jobs.
     */
    public Map map(List nodes, List chromosomeKeys) throws IgniteException {

        Map map = new HashMap<>();

        Affinity affinity = ignite.affinity(GAGridConstants.POPULATION_CACHE);

        Map> nodeKeys = affinity.mapKeysToNodes(chromosomeKeys);

        for (Map.Entry> entry : nodeKeys.entrySet()) {
            ClusterNode aNode = entry.getKey();
            map = setupCrossOver(aNode, (List)entry.getValue(), map);
        }
        return map;
    }

    /**
     * We return TRUE if success, else Exection is thrown.
     *
     * @param list ComputeJobResult
     * @return Boolean value; if operationa was successful return true, otherwise Exception
     */
    public Boolean reduce(List list) throws IgniteException {
        // TODO Auto-generated method stub
        return Boolean.TRUE;
    }

    /**
     * @param res ComputeJobResult
     * @param rcvd List of ComputeJobResult
     * @return ComputeJobResultPolicy
     */
    public ComputeJobResultPolicy result(ComputeJobResult res, List rcvd) {
        IgniteException err = res.getException();

        if (err != null)
            return ComputeJobResultPolicy.FAILOVER;

        // If there is no exception, wait for all job results.
        return ComputeJobResultPolicy.WAIT;

    }

    /**
     * Helper method to help assign ComputeJobs to respective ClusterNodes
     *
     * @param clusterNode
     * @param keys Primary keys of Chromosomes
     * @param map Nodes where jobs will be sent
     * @return A map of ComputeJob/ClusterNode's
     */
    private Map setupCrossOver(ClusterNode clusterNode, List keys,
        Map map) {
        // Calculate number of Jobs = keys / 2
        // as we desire pairs of Chromosomes to be swapped
        int numberOfJobs = keys.size() / 2;
        int k = 0;
        for (int i = 0; i < numberOfJobs; i++) {
            Long key1 = keys.get(k);
            Long key2 = keys.get(k + 1);

            CrossOverJob job = new CrossOverJob(key1, key2, this.config.getCrossOverRate());
            map.put(job, clusterNode);
            k = k + 2;
        }
        return map;
    }
}