1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.math4.legacy.fitting.leastsquares;
18
19 import org.apache.commons.math4.legacy.fitting.leastsquares.LeastSquaresProblem.Evaluation;
20 import org.apache.commons.math4.legacy.optim.ConvergenceChecker;
21 import org.apache.commons.numbers.core.Precision;
22
23 /**
24 * Check if an optimization has converged based on the change in computed RMS.
25 *
26 * @since 3.4
27 */
28 public class EvaluationRmsChecker implements ConvergenceChecker<Evaluation> {
29
30 /** relative tolerance for comparisons. */
31 private final double relTol;
32 /** absolute tolerance for comparisons. */
33 private final double absTol;
34
35 /**
36 * Create a convergence checker for the RMS with the same relative and absolute
37 * tolerance.
38 *
39 * <p>Convenience constructor for when the relative and absolute tolerances are the
40 * same. Same as {@code new EvaluationRmsChecker(tol, tol)}.
41 *
42 * @param tol the relative and absolute tolerance.
43 * @see #EvaluationRmsChecker(double, double)
44 */
45 public EvaluationRmsChecker(final double tol) {
46 this(tol, tol);
47 }
48
49 /**
50 * Create a convergence checker for the RMS with a relative and absolute tolerance.
51 *
52 * <p>The optimization has converged when the RMS of consecutive evaluations are equal
53 * to within the given relative tolerance or absolute tolerance.
54 *
55 * @param relTol the relative tolerance.
56 * @param absTol the absolute tolerance.
57 * @see Precision#equals(double, double, double)
58 * @see Precision#equalsWithRelativeTolerance(double, double, double)
59 */
60 public EvaluationRmsChecker(final double relTol, final double absTol) {
61 this.relTol = relTol;
62 this.absTol = absTol;
63 }
64
65 /** {@inheritDoc} */
66 @Override
67 public boolean converged(final int iteration,
68 final Evaluation previous,
69 final Evaluation current) {
70 final double prevRms = previous.getRMS();
71 final double currRms = current.getRMS();
72 return Precision.equals(prevRms, currRms, this.absTol) ||
73 Precision.equalsWithRelativeTolerance(prevRms, currRms, this.relTol);
74 }
75 }