/*
 * 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.math.estimation;

import java.util.ArrayList;
import java.util.HashSet;

import org.apache.commons.math.util.FastMath;

import junit.framework.TestCase;

/**
 * <p>Some of the unit tests are re-implementations of the MINPACK <a
 * href="http://www.netlib.org/minpack/ex/file17">file17</a> and <a
 * href="http://www.netlib.org/minpack/ex/file22">file22</a> test files.
 * The redistribution policy for MINPACK is available <a
 * href="http://www.netlib.org/minpack/disclaimer">here</a>, for
 * convenience, it is reproduced below.</p>

 * <table border="0" width="80%" cellpadding="10" align="center" bgcolor="#E0E0E0">
 * <tr><td>
 *    Minpack Copyright Notice (1999) University of Chicago.
 *    All rights reserved
 * </td></tr>
 * <tr><td>
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * <ol>
 *  <li>Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.</li>
 * <li>Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.</li>
 * <li>The end-user documentation included with the redistribution, if any,
 *     must include the following acknowledgment:
 *     <code>This product includes software developed by the University of
 *           Chicago, as Operator of Argonne National Laboratory.</code>
 *     Alternately, this acknowledgment may appear in the software itself,
 *     if and wherever such third-party acknowledgments normally appear.</li>
 * <li><strong>WARRANTY DISCLAIMER. THE SOFTWARE IS SUPPLIED "AS IS"
 *     WITHOUT WARRANTY OF ANY KIND. THE COPYRIGHT HOLDER, THE
 *     UNITED STATES, THE UNITED STATES DEPARTMENT OF ENERGY, AND
 *     THEIR EMPLOYEES: (1) DISCLAIM ANY WARRANTIES, EXPRESS OR
 *     IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTIES
 *     OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE
 *     OR NON-INFRINGEMENT, (2) DO NOT ASSUME ANY LEGAL LIABILITY
 *     OR RESPONSIBILITY FOR THE ACCURACY, COMPLETENESS, OR
 *     USEFULNESS OF THE SOFTWARE, (3) DO NOT REPRESENT THAT USE OF
 *     THE SOFTWARE WOULD NOT INFRINGE PRIVATELY OWNED RIGHTS, (4)
 *     DO NOT WARRANT THAT THE SOFTWARE WILL FUNCTION
 *     UNINTERRUPTED, THAT IT IS ERROR-FREE OR THAT ANY ERRORS WILL
 *     BE CORRECTED.</strong></li>
 * <li><strong>LIMITATION OF LIABILITY. IN NO EVENT WILL THE COPYRIGHT
 *     HOLDER, THE UNITED STATES, THE UNITED STATES DEPARTMENT OF
 *     ENERGY, OR THEIR EMPLOYEES: BE LIABLE FOR ANY INDIRECT,
 *     INCIDENTAL, CONSEQUENTIAL, SPECIAL OR PUNITIVE DAMAGES OF
 *     ANY KIND OR NATURE, INCLUDING BUT NOT LIMITED TO LOSS OF
 *     PROFITS OR LOSS OF DATA, FOR ANY REASON WHATSOEVER, WHETHER
 *     SUCH LIABILITY IS ASSERTED ON THE BASIS OF CONTRACT, TORT
 *     (INCLUDING NEGLIGENCE OR STRICT LIABILITY), OR OTHERWISE,
 *     EVEN IF ANY OF SAID PARTIES HAS BEEN WARNED OF THE
 *     POSSIBILITY OF SUCH LOSS OR DAMAGES.</strong></li>
 * <ol></td></tr>
 * </table>

 * @author Argonne National Laboratory. MINPACK project. March 1980 (original fortran minpack tests)
 * @author Burton S. Garbow (original fortran minpack tests)
 * @author Kenneth E. Hillstrom (original fortran minpack tests)
 * @author Jorge J. More (original fortran minpack tests)
 * @author Luc Maisonobe (non-minpack tests and minpack tests Java translation)
 */
@Deprecated
public class GaussNewtonEstimatorTest
  extends TestCase {

  public GaussNewtonEstimatorTest(String name) {
    super(name);
  }

  public void testTrivial() throws EstimationException {
    LinearProblem problem =
      new LinearProblem(new LinearMeasurement[] {
        new LinearMeasurement(new double[] {2},
                              new EstimatedParameter[] {
                                 new EstimatedParameter("p0", 0)
                              }, 3.0)
      });
    GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
    estimator.estimate(problem);
    assertEquals(0, estimator.getRMS(problem), 1.0e-10);
    assertEquals(1.5,
                 problem.getUnboundParameters()[0].getEstimate(),
                 1.0e-10);
   }

  public void testQRColumnsPermutation() throws EstimationException {

    EstimatedParameter[] x = {
       new EstimatedParameter("p0", 0), new EstimatedParameter("p1", 0)
    };
    LinearProblem problem = new LinearProblem(new LinearMeasurement[] {
      new LinearMeasurement(new double[] { 1.0, -1.0 },
                            new EstimatedParameter[] { x[0], x[1] },
                            4.0),
      new LinearMeasurement(new double[] { 2.0 },
                            new EstimatedParameter[] { x[1] },
                            6.0),
      new LinearMeasurement(new double[] { 1.0, -2.0 },
                            new EstimatedParameter[] { x[0], x[1] },
                            1.0)
    });

    GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
    estimator.estimate(problem);
    assertEquals(0, estimator.getRMS(problem), 1.0e-10);
    assertEquals(7.0, x[0].getEstimate(), 1.0e-10);
    assertEquals(3.0, x[1].getEstimate(), 1.0e-10);

  }

  public void testNoDependency() throws EstimationException {
    EstimatedParameter[] p = new EstimatedParameter[] {
      new EstimatedParameter("p0", 0),
      new EstimatedParameter("p1", 0),
      new EstimatedParameter("p2", 0),
      new EstimatedParameter("p3", 0),
      new EstimatedParameter("p4", 0),
      new EstimatedParameter("p5", 0)
    };
    LinearProblem problem = new LinearProblem(new LinearMeasurement[] {
      new LinearMeasurement(new double[] {2}, new EstimatedParameter[] { p[0] }, 0.0),
      new LinearMeasurement(new double[] {2}, new EstimatedParameter[] { p[1] }, 1.1),
      new LinearMeasurement(new double[] {2}, new EstimatedParameter[] { p[2] }, 2.2),
      new LinearMeasurement(new double[] {2}, new EstimatedParameter[] { p[3] }, 3.3),
      new LinearMeasurement(new double[] {2}, new EstimatedParameter[] { p[4] }, 4.4),
      new LinearMeasurement(new double[] {2}, new EstimatedParameter[] { p[5] }, 5.5)
    });
  GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
  estimator.estimate(problem);
  assertEquals(0, estimator.getRMS(problem), 1.0e-10);
  for (int i = 0; i < p.length; ++i) {
    assertEquals(0.55 * i, p[i].getEstimate(), 1.0e-10);
  }
}

  public void testOneSet() throws EstimationException {

    EstimatedParameter[] p = {
       new EstimatedParameter("p0", 0),
       new EstimatedParameter("p1", 0),
       new EstimatedParameter("p2", 0)
    };
    LinearProblem problem = new LinearProblem(new LinearMeasurement[] {
      new LinearMeasurement(new double[] { 1.0 },
                            new EstimatedParameter[] { p[0] },
                            1.0),
      new LinearMeasurement(new double[] { -1.0, 1.0 },
                            new EstimatedParameter[] { p[0], p[1] },
                            1.0),
      new LinearMeasurement(new double[] { -1.0, 1.0 },
                            new EstimatedParameter[] { p[1], p[2] },
                            1.0)
    });

    GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
    estimator.estimate(problem);
    assertEquals(0, estimator.getRMS(problem), 1.0e-10);
    assertEquals(1.0, p[0].getEstimate(), 1.0e-10);
    assertEquals(2.0, p[1].getEstimate(), 1.0e-10);
    assertEquals(3.0, p[2].getEstimate(), 1.0e-10);

  }

  public void testTwoSets() throws EstimationException {
    EstimatedParameter[] p = {
      new EstimatedParameter("p0", 0),
      new EstimatedParameter("p1", 1),
      new EstimatedParameter("p2", 2),
      new EstimatedParameter("p3", 3),
      new EstimatedParameter("p4", 4),
      new EstimatedParameter("p5", 5)
    };

    double epsilon = 1.0e-7;
    LinearProblem problem = new LinearProblem(new LinearMeasurement[] {

      // 4 elements sub-problem
      new LinearMeasurement(new double[] {  2.0,  1.0,  4.0 },
                            new EstimatedParameter[] { p[0], p[1], p[3] },
                            2.0),
      new LinearMeasurement(new double[] { -4.0, -2.0,   3.0, -7.0 },
                           new EstimatedParameter[] { p[0], p[1], p[2], p[3] },
                           -9.0),
      new LinearMeasurement(new double[] {  4.0,  1.0,  -2.0,  8.0 },
                            new EstimatedParameter[] { p[0], p[1], p[2], p[3] },
                            2.0),
      new LinearMeasurement(new double[] { -3.0, -12.0, -1.0 },
                           new EstimatedParameter[] { p[1], p[2], p[3] },
                           2.0),

      // 2 elements sub-problem
      new LinearMeasurement(new double[] { epsilon, 1.0 },
                            new EstimatedParameter[] { p[4], p[5] },
                            1.0 + epsilon * epsilon),
      new LinearMeasurement(new double[] {  1.0, 1.0 },
                            new EstimatedParameter[] { p[4], p[5] },
                            2.0)

    });

    GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
    estimator.estimate(problem);
    assertEquals(0, estimator.getRMS(problem), 1.0e-10);
    assertEquals( 3.0, p[0].getEstimate(), 1.0e-10);
    assertEquals( 4.0, p[1].getEstimate(), 1.0e-10);
    assertEquals(-1.0, p[2].getEstimate(), 1.0e-10);
    assertEquals(-2.0, p[3].getEstimate(), 1.0e-10);
    assertEquals( 1.0 + epsilon, p[4].getEstimate(), 1.0e-10);
    assertEquals( 1.0 - epsilon, p[5].getEstimate(), 1.0e-10);

  }

  public void testNonInversible() {

    EstimatedParameter[] p = {
       new EstimatedParameter("p0", 0),
       new EstimatedParameter("p1", 0),
       new EstimatedParameter("p2", 0)
    };
    LinearMeasurement[] m = new LinearMeasurement[] {
      new LinearMeasurement(new double[] {  1.0, 2.0, -3.0 },
                            new EstimatedParameter[] { p[0], p[1], p[2] },
                            1.0),
      new LinearMeasurement(new double[] {  2.0, 1.0,  3.0 },
                            new EstimatedParameter[] { p[0], p[1], p[2] },
                            1.0),
      new LinearMeasurement(new double[] { -3.0, -9.0 },
                            new EstimatedParameter[] { p[0], p[2] },
                            1.0)
    };
    LinearProblem problem = new LinearProblem(m);

    GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
    try {
      estimator.estimate(problem);
      fail("an exception should have been caught");
    } catch (EstimationException ee) {
      // expected behavior
    }
  }

  public void testIllConditioned() throws EstimationException {
    EstimatedParameter[] p = {
      new EstimatedParameter("p0", 0),
      new EstimatedParameter("p1", 1),
      new EstimatedParameter("p2", 2),
      new EstimatedParameter("p3", 3)
    };

    LinearProblem problem1 = new LinearProblem(new LinearMeasurement[] {
      new LinearMeasurement(new double[] { 10.0, 7.0,  8.0,  7.0 },
                            new EstimatedParameter[] { p[0], p[1], p[2], p[3] },
                            32.0),
      new LinearMeasurement(new double[] {  7.0, 5.0,  6.0,  5.0 },
                            new EstimatedParameter[] { p[0], p[1], p[2], p[3] },
                            23.0),
      new LinearMeasurement(new double[] {  8.0, 6.0, 10.0,  9.0 },
                            new EstimatedParameter[] { p[0], p[1], p[2], p[3] },
                            33.0),
      new LinearMeasurement(new double[] {  7.0, 5.0,  9.0, 10.0 },
                            new EstimatedParameter[] { p[0], p[1], p[2], p[3] },
                            31.0)
    });
    GaussNewtonEstimator estimator1 = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
    estimator1.estimate(problem1);
    assertEquals(0, estimator1.getRMS(problem1), 1.0e-10);
    assertEquals(1.0, p[0].getEstimate(), 1.0e-10);
    assertEquals(1.0, p[1].getEstimate(), 1.0e-10);
    assertEquals(1.0, p[2].getEstimate(), 1.0e-10);
    assertEquals(1.0, p[3].getEstimate(), 1.0e-10);

    LinearProblem problem2 = new LinearProblem(new LinearMeasurement[] {
      new LinearMeasurement(new double[] { 10.0, 7.0,  8.1,  7.2 },
                            new EstimatedParameter[] { p[0], p[1], p[2], p[3] },
                            32.0),
      new LinearMeasurement(new double[] {  7.08, 5.04,  6.0,  5.0 },
                            new EstimatedParameter[] { p[0], p[1], p[2], p[3] },
                            23.0),
      new LinearMeasurement(new double[] {  8.0, 5.98, 9.89,  9.0 },
                             new EstimatedParameter[] { p[0], p[1], p[2], p[3] },
                            33.0),
      new LinearMeasurement(new double[] {  6.99, 4.99,  9.0, 9.98 },
                             new EstimatedParameter[] { p[0], p[1], p[2], p[3] },
                            31.0)
    });
    GaussNewtonEstimator estimator2 = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
    estimator2.estimate(problem2);
    assertEquals(0, estimator2.getRMS(problem2), 1.0e-10);
    assertEquals(-81.0, p[0].getEstimate(), 1.0e-8);
    assertEquals(137.0, p[1].getEstimate(), 1.0e-8);
    assertEquals(-34.0, p[2].getEstimate(), 1.0e-8);
    assertEquals( 22.0, p[3].getEstimate(), 1.0e-8);

  }

  public void testMoreEstimatedParametersSimple() {

    EstimatedParameter[] p = {
       new EstimatedParameter("p0", 7),
       new EstimatedParameter("p1", 6),
       new EstimatedParameter("p2", 5),
       new EstimatedParameter("p3", 4)
     };
    LinearProblem problem = new LinearProblem(new LinearMeasurement[] {
      new LinearMeasurement(new double[] { 3.0, 2.0 },
                             new EstimatedParameter[] { p[0], p[1] },
                             7.0),
      new LinearMeasurement(new double[] { 1.0, -1.0, 1.0 },
                             new EstimatedParameter[] { p[1], p[2], p[3] },
                             3.0),
      new LinearMeasurement(new double[] { 2.0, 1.0 },
                             new EstimatedParameter[] { p[0], p[2] },
                             5.0)
    });

    GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
    try {
        estimator.estimate(problem);
        fail("an exception should have been caught");
    } catch (EstimationException ee) {
        // expected behavior
    }

  }

  public void testMoreEstimatedParametersUnsorted() {
    EstimatedParameter[] p = {
      new EstimatedParameter("p0", 2),
      new EstimatedParameter("p1", 2),
      new EstimatedParameter("p2", 2),
      new EstimatedParameter("p3", 2),
      new EstimatedParameter("p4", 2),
      new EstimatedParameter("p5", 2)
    };
    LinearProblem problem = new LinearProblem(new LinearMeasurement[] {
      new LinearMeasurement(new double[] { 1.0, 1.0 },
                           new EstimatedParameter[] { p[0], p[1] },
                           3.0),
      new LinearMeasurement(new double[] { 1.0, 1.0, 1.0 },
                           new EstimatedParameter[] { p[2], p[3], p[4] },
                           12.0),
      new LinearMeasurement(new double[] { 1.0, -1.0 },
                           new EstimatedParameter[] { p[4], p[5] },
                           -1.0),
      new LinearMeasurement(new double[] { 1.0, -1.0, 1.0 },
                           new EstimatedParameter[] { p[3], p[2], p[5] },
                           7.0),
      new LinearMeasurement(new double[] { 1.0, -1.0 },
                           new EstimatedParameter[] { p[4], p[3] },
                           1.0)
    });

    GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
    try {
        estimator.estimate(problem);
        fail("an exception should have been caught");
    } catch (EstimationException ee) {
        // expected behavior
    }

  }

  public void testRedundantEquations() throws EstimationException {
    EstimatedParameter[] p = {
      new EstimatedParameter("p0", 1),
      new EstimatedParameter("p1", 1)
    };
    LinearProblem problem = new LinearProblem(new LinearMeasurement[] {
      new LinearMeasurement(new double[] { 1.0, 1.0 },
                             new EstimatedParameter[] { p[0], p[1] },
                             3.0),
      new LinearMeasurement(new double[] { 1.0, -1.0 },
                             new EstimatedParameter[] { p[0], p[1] },
                             1.0),
      new LinearMeasurement(new double[] { 1.0, 3.0 },
                             new EstimatedParameter[] { p[0], p[1] },
                             5.0)
    });

    GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
    estimator.estimate(problem);
    assertEquals(0, estimator.getRMS(problem), 1.0e-10);
    EstimatedParameter[] all = problem.getAllParameters();
    for (int i = 0; i < all.length; ++i) {
        assertEquals(all[i].getName().equals("p0") ? 2.0 : 1.0,
                     all[i].getEstimate(), 1.0e-10);
    }

  }

  public void testInconsistentEquations() throws EstimationException {
    EstimatedParameter[] p = {
      new EstimatedParameter("p0", 1),
      new EstimatedParameter("p1", 1)
    };
    LinearProblem problem = new LinearProblem(new LinearMeasurement[] {
      new LinearMeasurement(new double[] { 1.0, 1.0 },
                            new EstimatedParameter[] { p[0], p[1] },
                            3.0),
      new LinearMeasurement(new double[] { 1.0, -1.0 },
                            new EstimatedParameter[] { p[0], p[1] },
                            1.0),
      new LinearMeasurement(new double[] { 1.0, 3.0 },
                            new EstimatedParameter[] { p[0], p[1] },
                            4.0)
    });

    GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
    estimator.estimate(problem);
    assertTrue(estimator.getRMS(problem) > 0.1);

  }

  public void testBoundParameters() throws EstimationException {
      EstimatedParameter[] p = {
        new EstimatedParameter("unbound0", 2, false),
        new EstimatedParameter("unbound1", 2, false),
        new EstimatedParameter("bound",    2, true)
      };
      LinearProblem problem = new LinearProblem(new LinearMeasurement[] {
        new LinearMeasurement(new double[] { 1.0, 1.0, 1.0 },
                              new EstimatedParameter[] { p[0], p[1], p[2] },
                              3.0),
        new LinearMeasurement(new double[] { 1.0, -1.0, 1.0 },
                              new EstimatedParameter[] { p[0], p[1], p[2] },
                              1.0),
        new LinearMeasurement(new double[] { 1.0, 3.0, 2.0 },
                              new EstimatedParameter[] { p[0], p[1], p[2] },
                              7.0)
      });

      GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
      estimator.estimate(problem);
      assertTrue(estimator.getRMS(problem) < 1.0e-10);
      double[][] covariances = estimator.getCovariances(problem);
      int i0 = 0, i1 = 1;
      if (problem.getUnboundParameters()[0].getName().endsWith("1")) {
          i0 = 1;
          i1 = 0;
      }
      assertEquals(11.0 / 24, covariances[i0][i0], 1.0e-10);
      assertEquals(-3.0 / 24, covariances[i0][i1], 1.0e-10);
      assertEquals(-3.0 / 24, covariances[i1][i0], 1.0e-10);
      assertEquals( 3.0 / 24, covariances[i1][i1], 1.0e-10);

      double[] errors = estimator.guessParametersErrors(problem);
      assertEquals(0, errors[i0], 1.0e-10);
      assertEquals(0, errors[i1], 1.0e-10);

  }

  public void testMaxIterations() {
      Circle circle = new Circle(98.680, 47.345);
      circle.addPoint( 30.0,  68.0);
      circle.addPoint( 50.0,  -6.0);
      circle.addPoint(110.0, -20.0);
      circle.addPoint( 35.0,  15.0);
      circle.addPoint( 45.0,  97.0);
      try {
        GaussNewtonEstimator estimator = new GaussNewtonEstimator(4, 1.0e-14, 1.0e-14);
        estimator.estimate(circle);
        fail("an exception should have been caught");
      } catch (EstimationException ee) {
        // expected behavior
      }
    }

  public void testCircleFitting() throws EstimationException {
      Circle circle = new Circle(98.680, 47.345);
      circle.addPoint( 30.0,  68.0);
      circle.addPoint( 50.0,  -6.0);
      circle.addPoint(110.0, -20.0);
      circle.addPoint( 35.0,  15.0);
      circle.addPoint( 45.0,  97.0);
      GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-10, 1.0e-10);
      estimator.estimate(circle);
      double rms = estimator.getRMS(circle);
      assertEquals(1.768262623567235,  FastMath.sqrt(circle.getM()) * rms,  1.0e-10);
      assertEquals(69.96016176931406, circle.getRadius(), 1.0e-10);
      assertEquals(96.07590211815305, circle.getX(),      1.0e-10);
      assertEquals(48.13516790438953, circle.getY(),      1.0e-10);
    }

  public void testCircleFittingBadInit() {
    Circle circle = new Circle(-12, -12);
    double[][] points = new double[][] {
      {-0.312967,  0.072366}, {-0.339248,  0.132965}, {-0.379780,  0.202724},
      {-0.390426,  0.260487}, {-0.361212,  0.328325}, {-0.346039,  0.392619},
      {-0.280579,  0.444306}, {-0.216035,  0.470009}, {-0.149127,  0.493832},
      {-0.075133,  0.483271}, {-0.007759,  0.452680}, { 0.060071,  0.410235},
      { 0.103037,  0.341076}, { 0.118438,  0.273884}, { 0.131293,  0.192201},
      { 0.115869,  0.129797}, { 0.072223,  0.058396}, { 0.022884,  0.000718},
      {-0.053355, -0.020405}, {-0.123584, -0.032451}, {-0.216248, -0.032862},
      {-0.278592, -0.005008}, {-0.337655,  0.056658}, {-0.385899,  0.112526},
      {-0.405517,  0.186957}, {-0.415374,  0.262071}, {-0.387482,  0.343398},
      {-0.347322,  0.397943}, {-0.287623,  0.458425}, {-0.223502,  0.475513},
      {-0.135352,  0.478186}, {-0.061221,  0.483371}, { 0.003711,  0.422737},
      { 0.065054,  0.375830}, { 0.108108,  0.297099}, { 0.123882,  0.222850},
      { 0.117729,  0.134382}, { 0.085195,  0.056820}, { 0.029800, -0.019138},
      {-0.027520, -0.072374}, {-0.102268, -0.091555}, {-0.200299, -0.106578},
      {-0.292731, -0.091473}, {-0.356288, -0.051108}, {-0.420561,  0.014926},
      {-0.471036,  0.074716}, {-0.488638,  0.182508}, {-0.485990,  0.254068},
      {-0.463943,  0.338438}, {-0.406453,  0.404704}, {-0.334287,  0.466119},
      {-0.254244,  0.503188}, {-0.161548,  0.495769}, {-0.075733,  0.495560},
      { 0.001375,  0.434937}, { 0.082787,  0.385806}, { 0.115490,  0.323807},
      { 0.141089,  0.223450}, { 0.138693,  0.131703}, { 0.126415,  0.049174},
      { 0.066518, -0.010217}, {-0.005184, -0.070647}, {-0.080985, -0.103635},
      {-0.177377, -0.116887}, {-0.260628, -0.100258}, {-0.335756, -0.056251},
      {-0.405195, -0.000895}, {-0.444937,  0.085456}, {-0.484357,  0.175597},
      {-0.472453,  0.248681}, {-0.438580,  0.347463}, {-0.402304,  0.422428},
      {-0.326777,  0.479438}, {-0.247797,  0.505581}, {-0.152676,  0.519380},
      {-0.071754,  0.516264}, { 0.015942,  0.472802}, { 0.076608,  0.419077},
      { 0.127673,  0.330264}, { 0.159951,  0.262150}, { 0.153530,  0.172681},
      { 0.140653,  0.089229}, { 0.078666,  0.024981}, { 0.023807, -0.037022},
      {-0.048837, -0.077056}, {-0.127729, -0.075338}, {-0.221271, -0.067526}
    };
    for (int i = 0; i < points.length; ++i) {
      circle.addPoint(points[i][0], points[i][1]);
    }
    GaussNewtonEstimator estimator = new GaussNewtonEstimator(100, 1.0e-6, 1.0e-6);
    try {
        estimator.estimate(circle);
        fail("an exception should have been caught");
    } catch (EstimationException ee) {
        // expected behavior
    }
}

  private static class LinearProblem extends SimpleEstimationProblem {

    public LinearProblem(LinearMeasurement[] measurements) {
      HashSet<EstimatedParameter> set = new HashSet<EstimatedParameter>();
      for (int i = 0; i < measurements.length; ++i) {
        addMeasurement(measurements[i]);
        EstimatedParameter[] parameters = measurements[i].getParameters();
        for (int j = 0; j < parameters.length; ++j) {
          set.add(parameters[j]);
        }
      }
      for (EstimatedParameter p : set) {
        addParameter(p);
      }
    }

  }

  private static class LinearMeasurement extends WeightedMeasurement {

    public LinearMeasurement(double[] factors, EstimatedParameter[] parameters,
                             double setPoint) {
      super(1.0, setPoint, true);
      this.factors = factors;
      this.parameters = parameters;
      setIgnored(false);
    }

    @Override
    public double getTheoreticalValue() {
      double v = 0;
      for (int i = 0; i < factors.length; ++i) {
        v += factors[i] * parameters[i].getEstimate();
      }
      return v;
    }

    @Override
    public double getPartial(EstimatedParameter parameter) {
      for (int i = 0; i < parameters.length; ++i) {
        if (parameters[i] == parameter) {
          return factors[i];
        }
      }
      return 0;
    }

    public EstimatedParameter[] getParameters() {
      return parameters;
    }

    private double[] factors;
    private EstimatedParameter[] parameters;
    private static final long serialVersionUID = -3922448707008868580L;

  }

  private static class Circle implements EstimationProblem {

    public Circle(double cx, double cy) {
      this.cx = new EstimatedParameter("cx", cx);
      this.cy = new EstimatedParameter(new EstimatedParameter("cy", cy));
      points  = new ArrayList<PointModel>();
    }

    public void addPoint(double px, double py) {
      points.add(new PointModel(this, px, py));
    }

    public int getM() {
      return points.size();
    }

    public WeightedMeasurement[] getMeasurements() {
      return points.toArray(new PointModel[points.size()]);
    }

    public EstimatedParameter[] getAllParameters() {
      return new EstimatedParameter[] { cx, cy };
    }

    public EstimatedParameter[] getUnboundParameters() {
      return new EstimatedParameter[] { cx, cy };
    }

    public double getPartialRadiusX() {
      double dRdX = 0;
      for (PointModel point : points) {
        dRdX += point.getPartialDiX();
      }
      return dRdX / points.size();
    }

    public double getPartialRadiusY() {
      double dRdY = 0;
      for (PointModel point : points) {
        dRdY += point.getPartialDiY();
      }
      return dRdY / points.size();
    }

   public double getRadius() {
      double r = 0;
      for (PointModel point : points) {
        r += point.getCenterDistance();
      }
      return r / points.size();
    }

    public double getX() {
      return cx.getEstimate();
    }

    public double getY() {
      return cy.getEstimate();
    }

    private static class PointModel extends WeightedMeasurement {

      public PointModel(Circle circle, double px, double py) {
        super(1.0, 0.0);
        this.px = px;
        this.py = py;
        this.circle = circle;
      }

      @Override
      public double getPartial(EstimatedParameter parameter) {
        if (parameter == circle.cx) {
          return getPartialDiX() - circle.getPartialRadiusX();
        } else if (parameter == circle.cy) {
          return getPartialDiY() - circle.getPartialRadiusY();
        }
        return 0;
      }

      public double getCenterDistance() {
        double dx = px - circle.cx.getEstimate();
        double dy = py - circle.cy.getEstimate();
        return FastMath.sqrt(dx * dx + dy * dy);
      }

      public double getPartialDiX() {
        return (circle.cx.getEstimate() - px) / getCenterDistance();
      }

      public double getPartialDiY() {
        return (circle.cy.getEstimate() - py) / getCenterDistance();
      }

      @Override
      public double getTheoreticalValue() {
        return getCenterDistance() - circle.getRadius();
      }

      private double px;
      private double py;
      private transient final Circle circle;
      private static final long serialVersionUID = 1L;

    }

    private EstimatedParameter cx;
    private EstimatedParameter cy;
    private ArrayList<PointModel> points;

  }

}
