| /* |
| * 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.optimization.general; |
| |
| /** |
| * Available choices of update formulas for the β parameter |
| * in {@link NonLinearConjugateGradientOptimizer}. |
| * <p> |
| * The β parameter is used to compute the successive conjugate |
| * search directions. For non-linear conjugate gradients, there are |
| * two formulas to compute β: |
| * <ul> |
| * <li>Fletcher-Reeves formula</li> |
| * <li>Polak-Ribière formula</li> |
| * </ul> |
| * On the one hand, the Fletcher-Reeves formula is guaranteed to converge |
| * if the start point is close enough of the optimum whether the |
| * Polak-Ribière formula may not converge in rare cases. On the |
| * other hand, the Polak-Ribière formula is often faster when it |
| * does converge. Polak-Ribière is often used. |
| * <p> |
| * @see NonLinearConjugateGradientOptimizer |
| * @version $Revision: 758059 $ $Date: 2009-03-24 23:16:21 +0100 (mar. 24 mars 2009) $ |
| * @since 2.0 |
| */ |
| public enum ConjugateGradientFormula { |
| |
| /** Fletcher-Reeves formula. */ |
| FLETCHER_REEVES, |
| |
| /** Polak-Ribière formula. */ |
| POLAK_RIBIERE |
| |
| } |
