| /* |
| * 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.commons.math3.fitting.leastsquares; |
| |
| import java.util.ArrayList; |
| import org.apache.commons.math3.analysis.MultivariateVectorFunction; |
| import org.apache.commons.math3.analysis.MultivariateMatrixFunction; |
| import org.apache.commons.math3.geometry.euclidean.twod.Vector2D; |
| |
| /** |
| * Class used in the tests. |
| */ |
| class CircleVectorial { |
| private ArrayList<Vector2D> points; |
| |
| public CircleVectorial() { |
| points = new ArrayList<Vector2D>(); |
| } |
| |
| public void addPoint(double px, double py) { |
| points.add(new Vector2D(px, py)); |
| } |
| |
| public int getN() { |
| return points.size(); |
| } |
| |
| public double getRadius(Vector2D center) { |
| double r = 0; |
| for (Vector2D point : points) { |
| r += point.distance(center); |
| } |
| return r / points.size(); |
| } |
| |
| public MultivariateVectorFunction getModelFunction() { |
| return new MultivariateVectorFunction() { |
| public double[] value(double[] params) { |
| Vector2D center = new Vector2D(params[0], params[1]); |
| double radius = getRadius(center); |
| double[] residuals = new double[points.size()]; |
| for (int i = 0; i < residuals.length; i++) { |
| residuals[i] = points.get(i).distance(center) - radius; |
| } |
| |
| return residuals; |
| } |
| }; |
| } |
| |
| public MultivariateMatrixFunction getModelFunctionJacobian() { |
| return new MultivariateMatrixFunction() { |
| public double[][] value(double[] params) { |
| final int n = points.size(); |
| final Vector2D center = new Vector2D(params[0], params[1]); |
| |
| double dRdX = 0; |
| double dRdY = 0; |
| for (Vector2D pk : points) { |
| double dk = pk.distance(center); |
| dRdX += (center.getX() - pk.getX()) / dk; |
| dRdY += (center.getY() - pk.getY()) / dk; |
| } |
| dRdX /= n; |
| dRdY /= n; |
| |
| // Jacobian of the radius residuals. |
| double[][] jacobian = new double[n][2]; |
| for (int i = 0; i < n; i++) { |
| final Vector2D pi = points.get(i); |
| final double di = pi.distance(center); |
| jacobian[i][0] = (center.getX() - pi.getX()) / di - dRdX; |
| jacobian[i][1] = (center.getY() - pi.getY()) / di - dRdY; |
| } |
| |
| return jacobian; |
| } |
| }; |
| } |
| } |