| /** |
| * 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 com.datatorrent.lib.statistics; |
| |
| import com.datatorrent.api.Context.OperatorContext; |
| import com.datatorrent.api.DefaultInputPort; |
| import com.datatorrent.api.DefaultOutputPort; |
| import com.datatorrent.api.annotation.OperatorAnnotation; |
| |
| import com.datatorrent.lib.util.BaseNumberValueOperator; |
| |
| /** |
| * An implementation of BaseOperator that computes weighted mean of incoming data. <br> |
| * <p> |
| * <b>Input Port(s) : </b><br> |
| * <b>data : </b> Data values input port. <br> |
| * <b>weight : </b> Current input data weight. <br> |
| * <br> |
| * <b>Output Port(s) : </b> <br> |
| * <b>mean : </b>Weighted mean output port. <br> |
| * <br> |
| * <b>StateFull : Yes</b>, value are aggregated over application window. <br> |
| * <b>Partitions : No</b>, no will yeild wrong results. <br> |
| * <br> |
| * @displayName Weighted Mean |
| * @category Stats and Aggregations |
| * @tags numeric, math, calculation, sum, count, mean operator, average |
| * @since 0.3.4 |
| */ |
| @OperatorAnnotation(partitionable = false) |
| public class WeightedMeanOperator<V extends Number> extends BaseNumberValueOperator<V> |
| { |
| // aggregate weighted sum |
| private double weightedSum; |
| |
| // aggregate weighted count |
| private double weightedCount; |
| |
| // current input weight |
| private double currentWeight; |
| |
| /** |
| * Input data port that takes a number. |
| */ |
| public final transient DefaultInputPort<V> data = new DefaultInputPort<V>() |
| { |
| /** |
| * Computes sum and count with each tuple |
| */ |
| @Override |
| public void process(V tuple) |
| { |
| weightedSum += currentWeight * tuple.doubleValue(); |
| weightedCount += currentWeight; |
| } |
| }; |
| |
| /** |
| * Input weight port that takes a number. |
| */ |
| public final transient DefaultInputPort<V> weight = new DefaultInputPort<V>() |
| { |
| /** |
| * Computes sum and count with each tuple |
| */ |
| @Override |
| public void process(V tuple) |
| { |
| if (tuple.doubleValue() != 0.0) { |
| currentWeight = tuple.doubleValue(); |
| } |
| } |
| }; |
| |
| /** |
| * Output port that emits weighted mean. |
| */ |
| public final transient DefaultOutputPort<V> mean = new DefaultOutputPort<V>(); |
| |
| @Override |
| public void setup(OperatorContext arg0) |
| { |
| currentWeight = 1.0; |
| } |
| |
| @Override |
| public void endWindow() |
| { |
| if (weightedCount != 0.0) { |
| mean.emit(getAverage()); |
| } |
| weightedSum = 0.0; |
| weightedCount = 0.0; |
| } |
| |
| /** |
| * Calculate average based on number type. |
| */ |
| @SuppressWarnings("unchecked") |
| public V getAverage() |
| { |
| if (weightedSum == 0) { |
| return null; |
| } |
| V num = getValue(weightedSum); |
| Number val; |
| switch (getType()) { |
| case DOUBLE: |
| val = num.doubleValue() / weightedCount; |
| break; |
| case INTEGER: |
| val = (int)(num.intValue() / weightedCount); |
| break; |
| case FLOAT: |
| val = new Float(num.floatValue() / weightedCount); |
| break; |
| case LONG: |
| val = (long)(num.longValue() / weightedCount); |
| break; |
| case SHORT: |
| val = (short)(num.shortValue() / weightedCount); |
| break; |
| default: |
| val = num.doubleValue() / weightedCount; |
| break; |
| } |
| return (V)val; |
| } |
| } |