| /* |
| * 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; |
| |
| /** This interface specifies how to check if an {@link MultivariateRealOptimizer optimization |
| * algorithm} has converged. |
| * |
| * <p>Deciding if convergence has been reached is a problem-dependent issue. The |
| * user should provide a class implementing this interface to allow the optimization |
| * algorithm to stop its search according to the problem at hand.</p> |
| * <p>For convenience, two implementations that fit simple needs are already provided: |
| * {@link SimpleScalarValueChecker} and {@link SimpleRealPointChecker}. The first |
| * one considers convergence is reached when the objective function value does not |
| * change much anymore, it does not use the point set at all. The second one |
| * considers convergence is reached when the input point set does not change |
| * much anymore, it does not use objective function value at all.</p> |
| * |
| * @version $Revision: 799857 $ $Date: 2009-08-01 15:07:12 +0200 (sam. 01 août 2009) $ |
| * @since 2.0 |
| */ |
| |
| public interface RealConvergenceChecker { |
| |
| /** Check if the optimization algorithm has converged considering the last points. |
| * <p> |
| * This method may be called several time from the same algorithm iteration with |
| * different points. This can be detected by checking the iteration number at each |
| * call if needed. Each time this method is called, the previous and current point |
| * correspond to points with the same role at each iteration, so they can be |
| * compared. As an example, simplex-based algorithms call this method for all |
| * points of the simplex, not only for the best or worst ones. |
| * </p> |
| * @param iteration index of current iteration |
| * @param previous point from previous iteration |
| * @param current point from current iteration |
| * @return true if the algorithm is considered to have converged |
| */ |
| boolean converged(int iteration, RealPointValuePair previous, RealPointValuePair current); |
| |
| } |
