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.utils.math;
020
021
022/**
023 * A sparse vector represented by an index and value array.
024 */
025public final class SparseVector extends AbstractImmutableVector {
026
027  private final double[] values;
028  private final int[] indices;
029  private final int size;
030
031
032  public SparseVector(final double[] values, final int[] indices, final int size) {
033    this.values = values;
034    this.indices = indices;
035    this.size = size;
036  }
037
038  public SparseVector(final double[] values, final int[] indices) {
039    this(values, indices, -1);
040  }
041
042
043  @Override
044  public double get(final int index) {
045    for (int i = 0; i < indices.length; ++i) {
046      if (indices[i] == index) {
047        return values[i];
048      }
049    }
050    return 0;
051  }
052
053  @Override
054  public int size() {
055    return this.size;
056  }
057}