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 */ 17package org.apache.commons.math; 18 19 20/** 21 * Interface for algorithms handling convergence settings. 22 * <p> 23 * This interface only deals with convergence parameters setting, not 24 * execution of the algorithms per se. 25 * </p> 26 * @see ConvergenceException 27 * @version $Revision: 1042336 $ $Date: 2010-12-05 13:40:48 +0100 (dim. 05 déc. 2010) $ 28 * @since 2.0 29 * @deprecated in 2.2 (to be removed in 3.0). The concept of "iteration" will 30 * be moved to a new {@code IterativeAlgorithm}. The concept of "accuracy" is 31 * currently is also contained in {@link org.apache.commons.math.optimization.SimpleRealPointChecker} 32 * and similar classes. 33 */ 34@Deprecated 35public interface ConvergingAlgorithm { 36 37 /** 38 * Set the upper limit for the number of iterations. 39 * <p> 40 * Usually a high iteration count indicates convergence problems. However, 41 * the "reasonable value" varies widely for different algorithms. Users are 42 * advised to use the default value supplied by the algorithm.</p> 43 * <p> 44 * A {@link ConvergenceException} will be thrown if this number 45 * is exceeded.</p> 46 * 47 * @param count maximum number of iterations 48 */ 49 void setMaximalIterationCount(int count); 50 51 /** 52 * Get the upper limit for the number of iterations. 53 * 54 * @return the actual upper limit 55 */ 56 int getMaximalIterationCount(); 57 58 /** 59 * Reset the upper limit for the number of iterations to the default. 60 * <p> 61 * The default value is supplied by the algorithm implementation.</p> 62 * 63 * @see #setMaximalIterationCount(int) 64 */ 65 void resetMaximalIterationCount(); 66 67 /** 68 * Set the absolute accuracy. 69 * <p> 70 * The default is usually chosen so that results in the interval 71 * -10..-0.1 and +0.1..+10 can be found with a reasonable accuracy. If the 72 * expected absolute value of your results is of much smaller magnitude, set 73 * this to a smaller value.</p> 74 * <p> 75 * Algorithms are advised to do a plausibility check with the relative 76 * accuracy, but clients should not rely on this.</p> 77 * 78 * @param accuracy the accuracy. 79 * @throws IllegalArgumentException if the accuracy can't be achieved by 80 * the solver or is otherwise deemed unreasonable. 81 */ 82 void setAbsoluteAccuracy(double accuracy); 83 84 /** 85 * Get the actual absolute accuracy. 86 * 87 * @return the accuracy 88 */ 89 double getAbsoluteAccuracy(); 90 91 /** 92 * Reset the absolute accuracy to the default. 93 * <p> 94 * The default value is provided by the algorithm implementation.</p> 95 */ 96 void resetAbsoluteAccuracy(); 97 98 /** 99 * Set the relative accuracy. 100 * <p> 101 * This is used to stop iterations if the absolute accuracy can't be 102 * achieved due to large values or short mantissa length.</p> 103 * <p> 104 * If this should be the primary criterion for convergence rather then a 105 * safety measure, set the absolute accuracy to a ridiculously small value, 106 * like {@link org.apache.commons.math.util.MathUtils#SAFE_MIN MathUtils.SAFE_MIN}.</p> 107 * 108 * @param accuracy the relative accuracy. 109 * @throws IllegalArgumentException if the accuracy can't be achieved by 110 * the algorithm or is otherwise deemed unreasonable. 111 */ 112 void setRelativeAccuracy(double accuracy); 113 114 /** 115 * Get the actual relative accuracy. 116 * @return the accuracy 117 */ 118 double getRelativeAccuracy(); 119 120 /** 121 * Reset the relative accuracy to the default. 122 * The default value is provided by the algorithm implementation. 123 */ 124 void resetRelativeAccuracy(); 125 126 /** 127 * Get the number of iterations in the last run of the algorithm. 128 * <p> 129 * This is mainly meant for testing purposes. It may occasionally 130 * help track down performance problems: if the iteration count 131 * is notoriously high, check whether the problem is evaluated 132 * properly, and whether another algorithm is more amenable to the 133 * problem.</p> 134 * 135 * @return the last iteration count. 136 * @throws IllegalStateException if there is no result available, either 137 * because no result was yet computed or the last attempt failed. 138 */ 139 int getIterationCount(); 140 141} 142