View Javadoc
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  
18  package org.apache.commons.math3.optimization.general;
19  
20  /**
21   * Available choices of update formulas for the β parameter
22   * in {@link NonLinearConjugateGradientOptimizer}.
23   * <p>
24   * The &beta; parameter is used to compute the successive conjugate
25   * search directions. For non-linear conjugate gradients, there are
26   * two formulas to compute &beta;:
27   * <ul>
28   *   <li>Fletcher-Reeves formula</li>
29   *   <li>Polak-Ribi&egrave;re formula</li>
30   * </ul>
31   * On the one hand, the Fletcher-Reeves formula is guaranteed to converge
32   * if the start point is close enough of the optimum whether the
33   * Polak-Ribi&egrave;re formula may not converge in rare cases. On the
34   * other hand, the Polak-Ribi&egrave;re formula is often faster when it
35   * does converge. Polak-Ribi&egrave;re is often used.
36   * <p>
37   * @see NonLinearConjugateGradientOptimizer
38   * @deprecated As of 3.1 (to be removed in 4.0).
39   * @since 2.0
40   */
41  @Deprecated
42  public enum ConjugateGradientFormula {
43  
44      /** Fletcher-Reeves formula. */
45      FLETCHER_REEVES,
46  
47      /** Polak-Ribi&egrave;re formula. */
48      POLAK_RIBIERE
49  
50  }