| /* |
| * 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.giraph.utils; |
| |
| import org.apache.hadoop.io.DoubleWritable; |
| |
| import java.util.Iterator; |
| |
| /** |
| * A helper class for math related operations with writables |
| */ |
| public class MathUtils { |
| |
| /** |
| * Utility classes cannot be instantiated |
| */ |
| private MathUtils() { |
| } |
| |
| /** |
| * Sums up a sequence of double values |
| * @param values double values |
| * @return sum of double values |
| */ |
| public static double sum(Iterable<DoubleWritable> values) { |
| return sum(values.iterator()); |
| } |
| |
| /** |
| * Sums up a sequence of double values |
| * @param values double values |
| * @return sum of double values |
| */ |
| public static double sum(Iterator<DoubleWritable> values) { |
| double sum = 0; |
| while (values.hasNext()) { |
| sum += values.next().get(); |
| } |
| return sum; |
| } |
| } |