| /* |
| * 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.solr.client.solrj.io.eval; |
| |
| import java.io.IOException; |
| import java.util.List; |
| import java.util.ArrayList; |
| import java.util.Map; |
| |
| import org.apache.commons.math3.analysis.interpolation.LoessInterpolator; |
| import org.apache.commons.math3.analysis.polynomials.PolynomialSplineFunction; |
| import org.apache.solr.client.solrj.io.Tuple; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpression; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionNamedParameter; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamFactory; |
| |
| public class LoessEvaluator extends RecursiveNumericEvaluator implements ManyValueWorker { |
| protected static final long serialVersionUID = 1L; |
| |
| private double bandwidth = .25; |
| private int robustIterations = 2; |
| |
| public LoessEvaluator(StreamExpression expression, StreamFactory factory) throws IOException{ |
| super(expression, factory); |
| |
| List<StreamExpressionNamedParameter> namedParams = factory.getNamedOperands(expression); |
| |
| for(StreamExpressionNamedParameter namedParam : namedParams){ |
| if(namedParam.getName().equals("bandwidth")){ |
| this.bandwidth = Double.parseDouble(namedParam.getParameter().toString().trim()); |
| } else if(namedParam.getName().equals("robustIterations")) { |
| this.robustIterations = Integer.parseInt(namedParam.getParameter().toString().trim()); |
| } else { |
| throw new IOException("Unexpected named parameter:"+namedParam.getName()); |
| } |
| } |
| |
| } |
| |
| @Override |
| @SuppressWarnings({"unchecked"}) |
| public Object doWork(Object... objects) throws IOException{ |
| |
| Object first = objects[0]; |
| |
| double[] x = null; |
| double[] y = null; |
| |
| if(objects.length == 1) { |
| //Only the y values passed |
| y = ((List) first).stream().mapToDouble(value -> ((Number) value).doubleValue()).toArray(); |
| x = new double[y.length]; |
| for(int i=0; i<y.length; i++) { |
| x[i] = i; |
| } |
| } else if(objects.length == 2) { |
| Object second = objects[1]; |
| x = ((List) first).stream().mapToDouble(value -> ((Number) value).doubleValue()).toArray(); |
| y = ((List) second).stream().mapToDouble(value -> ((Number) value).doubleValue()).toArray(); |
| } |
| |
| LoessInterpolator interpolator = new LoessInterpolator(bandwidth, robustIterations); |
| double[] smooth = interpolator.smooth(x, y); |
| |
| List<Number> list = new ArrayList<>(); |
| for(double yvalue : smooth) { |
| list.add(yvalue); |
| } |
| |
| PolynomialSplineFunction spline = interpolator.interpolate(x, y); |
| |
| VectorFunction vec = new VectorFunction(spline, list); |
| vec.addToContext("x", x); |
| vec.addToContext("y", y); |
| |
| return vec; |
| } |
| |
| |
| public static class LoessRegressionTuple extends Tuple { |
| private PolynomialSplineFunction spline; |
| |
| public LoessRegressionTuple(PolynomialSplineFunction spline, Map<?,?> map) { |
| super(map); |
| this.spline = spline; |
| } |
| |
| public double predict(double value) { |
| return spline.value(value); |
| } |
| } |
| } |