Source code

001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.reef.examples.group.bgd;
020
021import org.apache.reef.examples.group.utils.math.DenseVector;
022import org.apache.reef.examples.group.utils.math.Vector;
023import org.apache.reef.io.network.group.api.operators.Reduce;
024import org.apache.reef.io.network.util.Pair;
025
026import javax.inject.Inject;
027
028/**
029 * Reduce function implementing line search.
030 */
031public class LineSearchReduceFunction implements Reduce.ReduceFunction<Pair<Vector, Integer>> {
032
033  @Inject
034  public LineSearchReduceFunction() {
035  }
036
037  @Override
038  public Pair<Vector, Integer> apply(final Iterable<Pair<Vector, Integer>> evals) {
039
040    Vector combinedEvaluations = null;
041    int numEx = 0;
042
043    for (final Pair<Vector, Integer> eval : evals) {
044      if (combinedEvaluations == null) {
045        combinedEvaluations = new DenseVector(eval.getFirst());
046      } else {
047        combinedEvaluations.add(eval.getFirst());
048      }
049      numEx += eval.getSecond();
050    }
051
052    return new Pair<>(combinedEvaluations, numEx);
053  }
054}