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+/*
+ * 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;
+
+
+/**
+ * Interface for algorithms handling convergence settings.
+ * <p>
+ * This interface only deals with convergence parameters setting, not
+ * execution of the algorithms per se.
+ * </p>
+ * @see ConvergenceException
+ * @version $Revision: 1042336 $ $Date: 2010-12-05 13:40:48 +0100 (dim. 05 déc. 2010) $
+ * @since 2.0
+ * @deprecated in 2.2 (to be removed in 3.0). The concept of "iteration" will
+ * be moved to a new {@code IterativeAlgorithm}. The concept of "accuracy" is
+ * currently is also contained in {@link org.apache.commons.math.optimization.SimpleRealPointChecker}
+ * and similar classes.
+ */
+@Deprecated
+public interface ConvergingAlgorithm {
+
+    /**
+     * Set the upper limit for the number of iterations.
+     * <p>
+     * Usually a high iteration count indicates convergence problems. However,
+     * the "reasonable value" varies widely for different algorithms. Users are
+     * advised to use the default value supplied by the algorithm.</p>
+     * <p>
+     * A {@link ConvergenceException} will be thrown if this number
+     * is exceeded.</p>
+     *
+     * @param count maximum number of iterations
+     */
+    void setMaximalIterationCount(int count);
+
+    /**
+     * Get the upper limit for the number of iterations.
+     *
+     * @return the actual upper limit
+     */
+    int getMaximalIterationCount();
+
+    /**
+     * Reset the upper limit for the number of iterations to the default.
+     * <p>
+     * The default value is supplied by the algorithm implementation.</p>
+     *
+     * @see #setMaximalIterationCount(int)
+     */
+    void resetMaximalIterationCount();
+
+    /**
+     * Set the absolute accuracy.
+     * <p>
+     * The default is usually chosen so that results in the interval
+     * -10..-0.1 and +0.1..+10 can be found with a reasonable accuracy. If the
+     * expected absolute value of your results is of much smaller magnitude, set
+     * this to a smaller value.</p>
+     * <p>
+     * Algorithms are advised to do a plausibility check with the relative
+     * accuracy, but clients should not rely on this.</p>
+     *
+     * @param accuracy the accuracy.
+     * @throws IllegalArgumentException if the accuracy can't be achieved by
+     * the solver or is otherwise deemed unreasonable.
+     */
+    void setAbsoluteAccuracy(double accuracy);
+
+    /**
+     * Get the actual absolute accuracy.
+     *
+     * @return the accuracy
+     */
+    double getAbsoluteAccuracy();
+
+    /**
+     * Reset the absolute accuracy to the default.
+     * <p>
+     * The default value is provided by the algorithm implementation.</p>
+     */
+    void resetAbsoluteAccuracy();
+
+    /**
+     * Set the relative accuracy.
+     * <p>
+     * This is used to stop iterations if the absolute accuracy can't be
+     * achieved due to large values or short mantissa length.</p>
+     * <p>
+     * If this should be the primary criterion for convergence rather then a
+     * safety measure, set the absolute accuracy to a ridiculously small value,
+     * like {@link org.apache.commons.math.util.MathUtils#SAFE_MIN MathUtils.SAFE_MIN}.</p>
+     *
+     * @param accuracy the relative accuracy.
+     * @throws IllegalArgumentException if the accuracy can't be achieved by
+     *  the algorithm or is otherwise deemed unreasonable.
+     */
+    void setRelativeAccuracy(double accuracy);
+
+    /**
+     * Get the actual relative accuracy.
+     * @return the accuracy
+     */
+    double getRelativeAccuracy();
+
+    /**
+     * Reset the relative accuracy to the default.
+     * The default value is provided by the algorithm implementation.
+     */
+    void resetRelativeAccuracy();
+
+    /**
+     * Get the number of iterations in the last run of the algorithm.
+     * <p>
+     * This is mainly meant for testing purposes. It may occasionally
+     * help track down performance problems: if the iteration count
+     * is notoriously high, check whether the problem is evaluated
+     * properly, and whether another algorithm is more amenable to the
+     * problem.</p>
+     *
+     * @return the last iteration count.
+     * @throws IllegalStateException if there is no result available, either
+     * because no result was yet computed or the last attempt failed.
+     */
+    int getIterationCount();
+
+}