org.apache.commons.math.analysis
Class UnivariateRealSolverImpl

java.lang.Object
  org.apache.commons.math.analysis.UnivariateRealSolverImpl

All Implemented Interfaces:

Serializable, UnivariateRealSolver

Direct Known Subclasses:

BisectionSolver, BrentSolver, NewtonSolver, SecantSolver

public abstract class UnivariateRealSolverImpl

extends Object

implements UnivariateRealSolver, Serializable

Provide a default implementation for several functions useful to generic solvers.

Version:

$Revision: 1.15 $ $Date: 2004/07/17 21:19:39 $

See Also:

Serialized Form

Field Summary

protected double	absoluteAccuracy Maximum absolute error.
protected double	defaultAbsoluteAccuracy Default maximum absolute error.
protected double	defaultFunctionValueAccuracy Default maximum error of function.
protected int	defaultMaximalIterationCount Default maximum number of iterations.
protected double	defaultRelativeAccuracy Default maximum relative error.
protected UnivariateRealFunction	f The function to solve.
protected double	functionValueAccuracy Maximum error of function.
protected int	iterationCount The last iteration count.
protected int	maximalIterationCount Maximum number of iterations.
protected double	relativeAccuracy Maximum relative error.
protected double	result The last computed root.
protected boolean	resultComputed Indicates where a root has been computed.
(package private) static long	serialVersionUID Serializable version identifier

Constructor Summary

protected

UnivariateRealSolverImpl(UnivariateRealFunction f, int defaultMaximalIterationCount, double defaultAbsoluteAccuracy) Construct a solver with given iteration count and accuracy.

Method Summary

protected void	clearResult() Convenience function for implementations.
double	getAbsoluteAccuracy() Get the actual absolute accuracy.
double	getFunctionValueAccuracy() Get the actual function value accuracy.
int	getIterationCount() Access the last iteration count.
int	getMaximalIterationCount() Get the upper limit for the number of iterations.
double	getRelativeAccuracy() Get the actual relative accuracy.
double	getResult() Access the last computed root.
protected boolean	isBracketing(double lower, double upper, UnivariateRealFunction f) Returns true iff the function takes opposite signs at the endpoints.
protected boolean	isSequence(double start, double mid, double end) Returns true if the arguments form a (strictly) increasing sequence
void	resetAbsoluteAccuracy() Reset the absolute accuracy to the default.
void	resetFunctionValueAccuracy() Reset the actual function accuracy to the default.
void	resetMaximalIterationCount() Reset the upper limit for the number of iterations to the default.
void	resetRelativeAccuracy() Reset the relative accuracy to the default.
void	setAbsoluteAccuracy(double accuracy) Set the absolute accuracy.
void	setFunctionValueAccuracy(double accuracy) Set the function value accuracy.
void	setMaximalIterationCount(int count) Set the upper limit for the number of iterations.
void	setRelativeAccuracy(double accuracy) Set the relative accuracy.
protected void	setResult(double result, int iterationCount) Convenience function for implementations.
protected void	verifyBracketing(double lower, double upper, UnivariateRealFunction f) Verifies that the endpoints specify an interval and the function takes opposite signs at the enpoints, throws IllegalArgumentException if not
protected void	verifyInterval(double lower, double upper) Verifies that the endpoints specify an interval, throws IllegalArgumentException if not
protected void	verifySequence(double lower, double initial, double upper) Verifies that lower < initial < upper throws IllegalArgumentException if not

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.commons.math.analysis.UnivariateRealSolver

solve, solve

Field Detail

serialVersionUID

static final long serialVersionUID

Serializable version identifier

See Also:

Constant Field Values

absoluteAccuracy

protected double absoluteAccuracy

Maximum absolute error.

relativeAccuracy

protected double relativeAccuracy

Maximum relative error.

functionValueAccuracy

protected double functionValueAccuracy

Maximum error of function.

maximalIterationCount

protected int maximalIterationCount

Maximum number of iterations.

defaultAbsoluteAccuracy

protected double defaultAbsoluteAccuracy

Default maximum absolute error.

defaultRelativeAccuracy

protected double defaultRelativeAccuracy

Default maximum relative error.

defaultFunctionValueAccuracy

protected double defaultFunctionValueAccuracy

Default maximum error of function.

defaultMaximalIterationCount

protected int defaultMaximalIterationCount

Default maximum number of iterations.

resultComputed

protected boolean resultComputed

Indicates where a root has been computed.

result

protected double result

The last computed root.

iterationCount

protected int iterationCount

The last iteration count.

f

protected UnivariateRealFunction f

The function to solve.

Constructor Detail

UnivariateRealSolverImpl

protected UnivariateRealSolverImpl(UnivariateRealFunction f,
                                   int defaultMaximalIterationCount,
                                   double defaultAbsoluteAccuracy)

Construct a solver with given iteration count and accuracy.

Parameters:

f - the function to solve.

defaultAbsoluteAccuracy - maximum absolute error

defaultMaximalIterationCount - maximum number of iterations

Throws:

IllegalArgumentException - if f is null or the defaultAbsoluteAccuracy is not valid

Method Detail

getResult

public double getResult()

Access the last computed root.

Specified by:

getResult in interface UnivariateRealSolver

Returns:

the last computed root

Throws:

IllegalStateException - if no root has been computed

getIterationCount

public int getIterationCount()

Access the last iteration count.

Specified by:

getIterationCount in interface UnivariateRealSolver

Returns:

the last iteration count

Throws:

IllegalStateException - if no root has been computed

setResult

protected final void setResult(double result,
                               int iterationCount)

Convenience function for implementations.

Parameters:

result - the result to set

iterationCount - the iteration count to set

clearResult

protected final void clearResult()

Convenience function for implementations.

setAbsoluteAccuracy

public void setAbsoluteAccuracy(double accuracy)

Set the absolute accuracy.

Specified by:

setAbsoluteAccuracy in interface UnivariateRealSolver

Parameters:

accuracy - the accuracy.

Throws:

IllegalArgumentException - if the accuracy can't be achieved by the solver or is otherwise deemed unreasonable.

getAbsoluteAccuracy

public double getAbsoluteAccuracy()

Get the actual absolute accuracy.

Specified by:

getAbsoluteAccuracy in interface UnivariateRealSolver

Returns:

the accuracy

resetAbsoluteAccuracy

public void resetAbsoluteAccuracy()

Reset the absolute accuracy to the default.

Specified by:

resetAbsoluteAccuracy in interface UnivariateRealSolver

setMaximalIterationCount

public void setMaximalIterationCount(int count)

Set the upper limit for the number of iterations.

Specified by:

setMaximalIterationCount in interface UnivariateRealSolver

Parameters:

count - maximum number of iterations

getMaximalIterationCount

public int getMaximalIterationCount()

Get the upper limit for the number of iterations.

Specified by:

getMaximalIterationCount in interface UnivariateRealSolver

Returns:

the actual upper limit

resetMaximalIterationCount

public void resetMaximalIterationCount()

Reset the upper limit for the number of iterations to the default.

Specified by:

resetMaximalIterationCount in interface UnivariateRealSolver

See Also:

UnivariateRealSolver.setMaximalIterationCount(int)

setRelativeAccuracy

public void setRelativeAccuracy(double accuracy)

Set the relative accuracy.

Specified by:

setRelativeAccuracy in interface UnivariateRealSolver

Parameters:

accuracy - the relative accuracy.

Throws:

IllegalArgumentException - if the accuracy can't be achieved by the solver or is otherwise deemed unreasonable.

getRelativeAccuracy

public double getRelativeAccuracy()

Get the actual relative accuracy.

Specified by:

getRelativeAccuracy in interface UnivariateRealSolver

Returns:

the accuracy

resetRelativeAccuracy

public void resetRelativeAccuracy()

Reset the relative accuracy to the default.

Specified by:

resetRelativeAccuracy in interface UnivariateRealSolver

setFunctionValueAccuracy

public void setFunctionValueAccuracy(double accuracy)

Set the function value accuracy.

Specified by:

setFunctionValueAccuracy in interface UnivariateRealSolver

Parameters:

accuracy - the accuracy.

Throws:

IllegalArgumentException - if the accuracy can't be achieved by the solver or is otherwise deemed unreasonable.

getFunctionValueAccuracy

public double getFunctionValueAccuracy()

Get the actual function value accuracy.

Specified by:

getFunctionValueAccuracy in interface UnivariateRealSolver

Returns:

the accuracy

resetFunctionValueAccuracy

public void resetFunctionValueAccuracy()

Reset the actual function accuracy to the default.

Specified by:

resetFunctionValueAccuracy in interface UnivariateRealSolver

isBracketing

protected boolean isBracketing(double lower,
                               double upper,
                               UnivariateRealFunction f)
                        throws FunctionEvaluationException

Returns true iff the function takes opposite signs at the endpoints.

Parameters:

lower - the lower endpoint

upper - the upper endpoint

f - the function

Returns:

true if f(lower) * f(upper) < 0

Throws:

FunctionEvaluationException - if an error occurs evaluating the function at the endpoints

isSequence

protected boolean isSequence(double start,
                             double mid,
                             double end)

Returns true if the arguments form a (strictly) increasing sequence

Parameters:

start - first number

mid - second number

end - third number

Returns:

true if the arguments form an increasing sequence

verifyInterval

protected void verifyInterval(double lower,
                              double upper)

Verifies that the endpoints specify an interval, throws IllegalArgumentException if not

Parameters:

lower - lower endpoint

upper - upper endpoint

Throws:

IllegalArgumentException

verifySequence

protected void verifySequence(double lower,
                              double initial,
                              double upper)

Verifies that lower < initial < upper throws IllegalArgumentException if not

Parameters:

lower - lower endpoint

initial - initial value

upper - upper endpoint

Throws:

IllegalArgumentException

verifyBracketing

protected void verifyBracketing(double lower,
                                double upper,
                                UnivariateRealFunction f)
                         throws FunctionEvaluationException

Verifies that the endpoints specify an interval and the function takes opposite signs at the enpoints, throws IllegalArgumentException if not

Parameters:

lower - lower endpoint

upper - upper endpoint

f - function

Throws:

IllegalArgumentException

FunctionEvaluationException - if an error occurs evaluating the function at the endpoints