org.apache.commons.math.analysis.solvers.BisectionSolver Maven / Gradle / Ivy
/*
* 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
* bisection algorithm for finding zeros of univariate real functions.
*
* The function should be continuous but not necessarily smooth.
*
* @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);
}
}