| /* |
| 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.edgent.analytics.math3.stat; |
| |
| import org.apache.commons.math3.stat.regression.OLSMultipleLinearRegression; |
| import org.apache.edgent.analytics.math3.json.JsonUnivariateAggregator; |
| |
| import com.google.gson.JsonElement; |
| import com.google.gson.JsonObject; |
| import org.apache.edgent.analytics.math3.utils.Java7Helper; |
| |
| class JsonOLS implements JsonUnivariateAggregator { |
| |
| private final Regression type; |
| private final OLSMultipleLinearRegression ols = new OLSMultipleLinearRegression(); |
| private double[] values; |
| private int yOffset; |
| |
| JsonOLS(Regression type) { |
| this.type = type; |
| } |
| |
| @Override |
| public void clear(JsonElement partition, int n) { |
| values = new double[n*2]; |
| yOffset = 0; |
| } |
| |
| @Override |
| public void increment(double v) { |
| values[yOffset] = v; |
| yOffset+=2; |
| } |
| |
| void setSampleData() { |
| // Fill in the x values |
| for (int x = 0; x < values.length/2; x++) |
| values[(x*2)+1] = x; |
| ols.newSampleData(values, values.length/2, 1); |
| } |
| @Override |
| public void result(JsonElement partition, JsonObject result) { |
| // If there are no values or only a single |
| // value then we cannot calculate tne slope. |
| if (values.length <= 2) |
| return; |
| |
| setSampleData(); |
| double[] regressionParams = ols.estimateRegressionParameters(); |
| if (regressionParams.length >= 2) { |
| // [0] is the constant (zero'th order) |
| // [1] is the first order , which we use as the slope. |
| final double slope = regressionParams[1]; |
| if (Java7Helper.doubleIsFinite(slope)) |
| result.addProperty(type.name(), slope); |
| } |
| values = null; |
| } |
| } |