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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.analysis.solvers;
+
+import org.apache.commons.math.FunctionEvaluationException;
+import org.apache.commons.math.MaxIterationsExceededException;
+import org.apache.commons.math.analysis.UnivariateRealFunction;
+import org.apache.commons.math.util.FastMath;
+
+/**
+ * Implements the <a href="http://mathworld.wolfram.com/Bisection.html">
+ * bisection algorithm</a> for finding zeros of univariate real functions.
+ * <p>
+ * The function should be continuous but not necessarily smooth.</p>
+ *
+ * @version $Revision: 1070725 $ $Date: 2011-02-15 02:31:12 +0100 (mar. 15 févr. 2011) $
+ */
+public class BisectionSolver extends UnivariateRealSolverImpl {
+
+ /**
+ * Construct a solver for the given function.
+ *
+ * @param f function to solve.
+ * @deprecated as of 2.0 the function to solve is passed as an argument
+ * to the {@link #solve(UnivariateRealFunction, double, double)} or
+ * {@link UnivariateRealSolverImpl#solve(UnivariateRealFunction, double, double, double)}
+ * method.
+ */
+ @Deprecated
+ public BisectionSolver(UnivariateRealFunction f) {
+ super(f, 100, 1E-6);
+ }
+
+ /**
+ * Construct a solver.
+ *
+ */
+ public BisectionSolver() {
+ super(100, 1E-6);
+ }
+
+ /** {@inheritDoc} */
+ @Deprecated
+ public double solve(double min, double max, double initial)
+ throws MaxIterationsExceededException, FunctionEvaluationException {
+ return solve(f, min, max);
+ }
+
+ /** {@inheritDoc} */
+ @Deprecated
+ public double solve(double min, double max)
+ throws MaxIterationsExceededException, FunctionEvaluationException {
+ return solve(f, min, max);
+ }
+
+ /**
+ * {@inheritDoc}
+ * @deprecated in 2.2 (to be removed in 3.0).
+ */
+ @Deprecated
+ public double solve(final UnivariateRealFunction f, double min, double max, double initial)
+ throws MaxIterationsExceededException, FunctionEvaluationException {
+ return solve(f, min, max);
+ }
+
+ /** {@inheritDoc} */
+ @Override
+ public double solve(int maxEval, final UnivariateRealFunction f, double min, double max, double initial)
+ throws MaxIterationsExceededException, FunctionEvaluationException {
+ return solve(maxEval, f, min, max);
+ }
+
+ /** {@inheritDoc} */
+ @Override
+ public double solve(int maxEval, final UnivariateRealFunction f, double min, double max)
+ throws MaxIterationsExceededException, FunctionEvaluationException {
+ setMaximalIterationCount(maxEval);
+ return solve(f, min, max);
+ }
+
+ /**
+ * {@inheritDoc}
+ * @deprecated in 2.2 (to be removed in 3.0).
+ */
+ @Deprecated
+ public double solve(final UnivariateRealFunction f, double min, double max)
+ throws MaxIterationsExceededException, FunctionEvaluationException {
+
+ clearResult();
+ verifyInterval(min,max);
+ double m;
+ double fm;
+ double fmin;
+
+ int i = 0;
+ while (i < maximalIterationCount) {
+ m = UnivariateRealSolverUtils.midpoint(min, max);
+ fmin = f.value(min);
+ fm = f.value(m);
+
+ if (fm * fmin > 0.0) {
+ // max and m bracket the root.
+ min = m;
+ } else {
+ // min and m bracket the root.
+ max = m;
+ }
+
+ if (FastMath.abs(max - min) <= absoluteAccuracy) {
+ m = UnivariateRealSolverUtils.midpoint(min, max);
+ setResult(m, i);
+ return m;
+ }
+ ++i;
+ }
+
+ throw new MaxIterationsExceededException(maximalIterationCount);
+ }
+}