/* * 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.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 * @deprecated As of 3.1 (to be removed in 4.0). * @since 2.0 */ @Deprecated public enum ConjugateGradientFormula { /** Fletcher-Reeves formula. */ FLETCHER_REEVES, /** Polak-Ribière formula. */ POLAK_RIBIERE }