Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||
UnivariateRealSolver |
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| 1.0;1 |
1 | /* |
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2 | * Copyright 2003-2004 The Apache Software Foundation. |
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3 | * |
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4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
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5 | * you may not use this file except in compliance with the License. |
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6 | * You may obtain a copy of the License at |
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7 | * |
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8 | * http://www.apache.org/licenses/LICENSE-2.0 |
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9 | * |
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10 | * Unless required by applicable law or agreed to in writing, software |
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11 | * distributed under the License is distributed on an "AS IS" BASIS, |
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12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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13 | * See the License for the specific language governing permissions and |
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14 | * limitations under the License. |
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15 | */ |
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16 | package org.apache.commons.math.analysis; |
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17 | ||
18 | import org.apache.commons.math.ConvergenceException; |
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19 | import org.apache.commons.math.FunctionEvaluationException; |
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20 | ||
21 | ||
22 | /** |
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23 | * Interface for (univariate real) rootfinding algorithms. |
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24 | * <p> |
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25 | * Implementations will search for only one zero in the given interval. |
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26 | * |
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27 | * @version $Revision$ $Date: 2005-02-26 05:11:52 -0800 (Sat, 26 Feb 2005) $ |
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28 | */ |
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29 | public interface UnivariateRealSolver { |
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30 | ||
31 | /** |
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32 | * Set the upper limit for the number of iterations. |
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33 | * <p> |
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34 | * Usually a high iteration count indicates convergence problems. However, |
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35 | * the "reasonable value" varies widely for different solvers. Users are |
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36 | * advised to use the default value supplied by the solver. |
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37 | * <p> |
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38 | * A <code>ConvergenceException</code> will be thrown if this number |
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39 | * is exceeded. |
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40 | * |
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41 | * @param count maximum number of iterations |
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42 | */ |
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43 | void setMaximalIterationCount(int count); |
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44 | ||
45 | /** |
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46 | * Get the upper limit for the number of iterations. |
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47 | * |
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48 | * @return the actual upper limit |
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49 | */ |
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50 | int getMaximalIterationCount(); |
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51 | ||
52 | /** |
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53 | * Reset the upper limit for the number of iterations to the default. |
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54 | * <p> |
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55 | * The default value is supplied by the solver implementation. |
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56 | * |
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57 | * @see #setMaximalIterationCount(int) |
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58 | */ |
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59 | void resetMaximalIterationCount(); |
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60 | ||
61 | /** |
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62 | * Set the absolute accuracy. |
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63 | * <p> |
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64 | * The default is usually choosen so that roots in the interval |
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65 | * -10..-0.1 and +0.1..+10 can be found with a reasonable accuracy. If the |
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66 | * expected absolute value of your roots is of much smaller magnitude, set |
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67 | * this to a smaller value. |
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68 | * <p> |
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69 | * Solvers are advised to do a plausibility check with the relative |
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70 | * accuracy, but clients should not rely on this. |
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71 | * |
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72 | * @param accuracy the accuracy. |
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73 | * @throws IllegalArgumentException if the accuracy can't be achieved by |
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74 | * the solver or is otherwise deemed unreasonable. |
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75 | */ |
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76 | void setAbsoluteAccuracy(double accuracy); |
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77 | ||
78 | /** |
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79 | * Get the actual absolute accuracy. |
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80 | * |
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81 | * @return the accuracy |
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82 | */ |
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83 | double getAbsoluteAccuracy(); |
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84 | ||
85 | /** |
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86 | * Reset the absolute accuracy to the default. |
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87 | * <p> |
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88 | * The default value is provided by the solver implementation. |
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89 | */ |
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90 | void resetAbsoluteAccuracy(); |
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91 | ||
92 | /** |
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93 | * Set the relative accuracy. |
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94 | * <p> |
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95 | * This is used to stop iterations if the absolute accuracy can't be |
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96 | * achieved due to large values or short mantissa length. |
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97 | * <p> |
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98 | * If this should be the primary criterion for convergence rather then a |
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99 | * safety measure, set the absolute accuracy to a ridiculously small value, |
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100 | * like 1E-1000. |
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101 | * |
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102 | * @param accuracy the relative accuracy. |
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103 | * @throws IllegalArgumentException if the accuracy can't be achieved by |
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104 | * the solver or is otherwise deemed unreasonable. |
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105 | */ |
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106 | void setRelativeAccuracy(double accuracy); |
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107 | ||
108 | /** |
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109 | * Get the actual relative accuracy. |
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110 | * @return the accuracy |
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111 | */ |
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112 | double getRelativeAccuracy(); |
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113 | ||
114 | /** |
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115 | * Reset the relative accuracy to the default. |
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116 | * The default value is provided by the solver implementation. |
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117 | */ |
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118 | void resetRelativeAccuracy(); |
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119 | ||
120 | /** |
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121 | * Set the function value accuracy. |
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122 | * <p> |
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123 | * This is used to determine whan an evaluated function value or some other |
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124 | * value which is used as divisor is zero. |
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125 | * <p> |
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126 | * This is a safety guard and it shouldn't be necesary to change this in |
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127 | * general. |
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128 | * |
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129 | * @param accuracy the accuracy. |
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130 | * @throws IllegalArgumentException if the accuracy can't be achieved by |
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131 | * the solver or is otherwise deemed unreasonable. |
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132 | */ |
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133 | void setFunctionValueAccuracy(double accuracy); |
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134 | ||
135 | /** |
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136 | * Get the actual function value accuracy. |
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137 | * @return the accuracy |
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138 | */ |
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139 | double getFunctionValueAccuracy(); |
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140 | ||
141 | /** |
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142 | * Reset the actual function accuracy to the default. |
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143 | * The default value is provided by the solver implementation. |
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144 | */ |
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145 | void resetFunctionValueAccuracy(); |
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146 | ||
147 | /** |
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148 | * Solve for a zero root in the given interval. |
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149 | * A solver may require that the interval brackets a single zero root. |
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150 | * |
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151 | * @param min the lower bound for the interval. |
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152 | * @param max the upper bound for the interval. |
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153 | * @return a value where the function is zero |
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154 | * @throws ConvergenceException if the maximum iteration count is exceeded |
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155 | * or the solver detects convergence problems otherwise. |
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156 | * @throws FunctionEvaluationException if an error occurs evaluating the |
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157 | * function |
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158 | * @throws IllegalArgumentException if min > max or the endpoints do not |
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159 | * satisfy the requirements specified by the solver |
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160 | */ |
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161 | double solve(double min, double max) throws ConvergenceException, |
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162 | FunctionEvaluationException; |
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163 | ||
164 | /** |
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165 | * Solve for a zero in the given interval, start at startValue. |
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166 | * A solver may require that the interval brackets a single zero root. |
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167 | * |
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168 | * @param min the lower bound for the interval. |
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169 | * @param max the upper bound for the interval. |
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170 | * @param startValue the start value to use |
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171 | * @return a value where the function is zero |
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172 | * @throws ConvergenceException if the maximum iteration count is exceeded |
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173 | * or the solver detects convergence problems otherwise. |
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174 | * @throws FunctionEvaluationException if an error occurs evaluating the |
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175 | * function |
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176 | * @throws IllegalArgumentException if min > max or the arguments do not |
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177 | * satisfy the requirements specified by the solver |
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178 | */ |
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179 | double solve(double min, double max, double startValue) |
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180 | throws ConvergenceException, FunctionEvaluationException; |
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181 | ||
182 | /** |
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183 | * Get the result of the last run of the solver. |
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184 | * |
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185 | * @return the last result. |
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186 | * @throws IllegalStateException if there is no result available, either |
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187 | * because no result was yet computed or the last attempt failed. |
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188 | */ |
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189 | double getResult(); |
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190 | ||
191 | /** |
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192 | * Get the number of iterations in the last run of the solver. |
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193 | * <p> |
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194 | * This is mainly meant for testing purposes. It may occasionally |
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195 | * help track down performance problems: if the iteration count |
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196 | * is notoriously high, check whether the function is evaluated |
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197 | * properly, and whether another solver is more amenable to the |
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198 | * problem. |
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199 | * |
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200 | * @return the last iteration count. |
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201 | * @throws IllegalStateException if there is no result available, either |
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202 | * because no result was yet computed or the last attempt failed. |
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203 | */ |
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204 | int getIterationCount(); |
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205 | } |