Package jsl.utilities.rootfinding

Class IPRootFinder

java.lang.Object

jsl.simulation.IterativeProcess<RootFinderStep>

jsl.utilities.rootfinding.IPRootFinder

All Implemented Interfaces:

ObservableIfc, IterativeProcessIfc, GetNameIfc

Direct Known Subclasses:

IPBisectionRootFinder, StochasticApproximationRootFinder

public abstract class IPRootFinder
extends IterativeProcess<RootFinderStep>

Nested Class Summary

Nested classes/interfaces inherited from class jsl.simulation.IterativeProcess

IterativeProcess.Created, IterativeProcess.Ended, IterativeProcess.Initialized, IterativeProcess.IterativeState, IterativeProcess.ShowElapsedTimeTask, IterativeProcess.StepCompleted

Field Summary

Fields

Modifier and Type	Field	Description
protected FunctionIfc	f	Function for which the zero should be found.
protected double	myInitialPt	The initial point for the search
protected Interval	myInterval	The interval for the search
protected int	myMaxIterations	The maximum number of iterations permitted to find the root The default is 100
protected static int	numIterations	Used in the static methods for finding intervals
protected static double	searchFactor	used in the static methods for finding intervals

Fields inherited from class jsl.simulation.IterativeProcess

COMPLETED_ALL_STEPS, COMPLETED_ALL_STEPS_MSG, EXCEEDED_EXECUTION_TIME, EXCEEDED_EXECUTION_TIME_MSG, MET_STOPPING_CONDITION, MET_STOPPING_CONDITION_MSG, myBeginExecutionTime, myCreatedState, myCurrentStep, myDoneFlag, myEndedState, myEndExecutionTime, myEndingStateIndicator, myId, myInitFlag, myInitializedState, myIPLogReport, myMaxAllowedExecutionTime, myName, myObservableComponent, myRunningFlag, myRunningStepFlag, mySaveStepOption, myState, myStepCompletedState, myStepCounter, mySteps, myTBConsoleUpdates, myTimer, myTimerTask, NO_STEPS_EXECUTED, NO_STEPS_EXECUTED_MSG, UNFINISHED, UNFINISHED_MSG

Constructor Summary

Constructors

Constructor	Description
IPRootFinder(FunctionIfc func, double xLower, double xUpper)	Defines a function and an interval for searching for a root
IPRootFinder(FunctionIfc func, Interval interval)	Defines a function and an interval for searching for a root

Method Summary

Modifier and Type	Method	Description
boolean	contains(double x)	Checks to see if the the supplied point is within the search interval
static boolean	findInterval(FunctionIfc func, Interval interval)	Using the supplied function and the initial interval provided, try to find a bracketing interval by expanding the interval outward
static java.util.List<Interval>	findInterval(FunctionIfc func, Interval interval, int n, int nmax)	Given a function and a starting interval, subdivide the interval into n subintervals and attempt to find nmax bracketing intervals that contain roots
double	getFunctionAtRoot()	Returns the value of the function at the last considered possible root of the function
double	getInitialPoint()	Returns the initial point used for the search
double	getLowerLimit()	The lower limit for the search interval
int	getMaxIterations()
double	getRoot()	Returns the last evaluated value that was considered for the root of the function
double	getUpperLimit()	The upper limit for the search interval
abstract boolean	hasConverged()	Check to see if the result has been attained.
boolean	hasIterations()	Returns true if the number of iterations is < max iterations
boolean	hasRoot(double xLower, double xUpper)	Returns true if the supplied interval contains a root
boolean	hasRoot(Interval interval)	Returns true if the supplied interval contains a root
static boolean	hasRoot(FunctionIfc func, double xLower, double xUpper)	Returns true if the supplied interval contains a root
double	recommendInitialPoint()	Enumerates equally spaced points in the interval and returns the point that has the function value closest to zero
double	recommendInitialPoint(int nmax)	Enumerates nmax equally spaced points in the interval and returns the point that has the function value closest to zero
double	relativePrecision(double epsilon)
double	relativePrecision(double epsilon, double x)
protected void	setFunction(FunctionIfc func)
void	setInitialPoint(double initialPt)	Sets the initial starting point for the search.
void	setInterval(double xLower, double xUpper)	Sets the bracketing interval within which the root should be found.
void	setInterval(Interval interval)	Sets the search interval for the search
void	setInterval(FunctionIfc func, double xLower, double xUpper)	Sets the bracketing interval within which the root should be found.
void	setInterval(FunctionIfc func, Interval interval)	Sets the bracketing interval within which the root should be found.
void	setMaxIterations(int maxIterations)
protected void	setRoot(double x)
java.lang.String	toString()	Returns a String representation of the finder

Methods inherited from class jsl.simulation.IterativeProcess

addObserver, allStepsCompleted, checkStoppingCondition, checkStoppingCondition_, consoleOutput, contains, countObservers, deleteObserver, deleteObservers, end, end, endIterations, executionTimeExceeded, getBeginExecutionTime, getCurrentStateAsString, getCurrentStep, getElapsedExecutionTime, getEndExecutionTime, getEndingStateIndicator, getEndingStateIndicatorAsString, getId, getLogReport, getMaximumAllowedExecutionTime, getName, getNumberStepsCompleted, getSaveStepOption, getStepIterator, getStepList, getStoppingFlag, getStoppingMessage, hasNext, initialize, initializeIterations, isCreated, isDone, isEnded, isExecutionTimeExceeded, isInitialized, isRunning, isRunningStep, isStepCompleted, isUnfinished, next, noStepsExecuted, run, runAll_, runNext, runNext_, runStep, setId, setMaximumExecutionTime, setName, setSaveStepOption, setState, stop, stop, stoppedByCondition, turnOffLogReport, turnOnLogReport, turnOnTimer

Methods inherited from class java.lang.Object

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

Field Detail

f

protected FunctionIfc f

Function for which the zero should be found.

myInterval

protected Interval myInterval

The interval for the search

myInitialPt

protected double myInitialPt

The initial point for the search

myMaxIterations

protected int myMaxIterations

The maximum number of iterations permitted to find the root The default is 100

numIterations

protected static int numIterations

Used in the static methods for finding intervals

searchFactor

protected static double searchFactor

used in the static methods for finding intervals

Constructor Detail

IPRootFinder

public IPRootFinder(FunctionIfc func,
                    Interval interval)

Defines a function and an interval for searching for a root

Parameters:

func - must not be null, must have a root in the interval

interval -

IPRootFinder

public IPRootFinder(FunctionIfc func,
                    double xLower,
                    double xUpper)

Defines a function and an interval for searching for a root

Parameters:

func - must not be null, must have a root in the interval

xLower - must be less than xUpper

xUpper - must be greater than xLower

Method Detail

getRoot

public double getRoot()

Returns the last evaluated value that was considered for the root of the function

getFunctionAtRoot

public double getFunctionAtRoot()

Returns the value of the function at the last considered possible root of the function

Returns:

relativePrecision

public double relativePrecision(double epsilon)

Parameters:

epsilon - double

Returns:

double

relativePrecision

public double relativePrecision(double epsilon,
                                double x)

Parameters:

epsilon - double

x - double

Returns:

double

getMaxIterations

public int getMaxIterations()

Returns:

the maximum number of iterations

setMaxIterations

public void setMaxIterations(int maxIterations)

Parameters:

maxIterations - the maximum number of iterations

hasIterations

public boolean hasIterations()

Returns true if the number of iterations is < max iterations

Returns:

hasRoot

public final boolean hasRoot(Interval interval)

Returns true if the supplied interval contains a root

Parameters:

interval -

Returns:

hasRoot

public boolean hasRoot(double xLower,
                       double xUpper)

Returns true if the supplied interval contains a root

Parameters:

xLower -

xUpper -

Returns:

hasRoot

public static boolean hasRoot(FunctionIfc func,
                              double xLower,
                              double xUpper)

Returns true if the supplied interval contains a root

Parameters:

func -

xLower -

xUpper -

Returns:

findInterval

public static boolean findInterval(FunctionIfc func,
                                   Interval interval)

Using the supplied function and the initial interval provided, try to find a bracketing interval by expanding the interval outward

Parameters:

func -

interval -

Returns:

findInterval

public static java.util.List<Interval> findInterval(FunctionIfc func,
                                                    Interval interval,
                                                    int n,
                                                    int nmax)

Given a function and a starting interval, subdivide the interval into n subintervals and attempt to find nmax bracketing intervals that contain roots

Parameters:

func -

interval -

n -

nmax -

Returns:

The list of bracketing intervals

setInterval

public final void setInterval(Interval interval)

Sets the search interval for the search

Parameters:

interval -

setInterval

public void setInterval(double xLower,
                        double xUpper)

Sets the bracketing interval within which the root should be found. Throws IllegalArgumentExceptons if the lower limit is > upper limit and if the function does not cross the axis within the provided interval.

Parameters:

xLower -

xUpper -

getInitialPoint

public double getInitialPoint()

Returns the initial point used for the search

Returns:

setInitialPoint

public void setInitialPoint(double initialPt)

Sets the initial starting point for the search. The starting point must be in the interval defined for the search or an IllegalArgumentException will be thrown.

Parameters:

initialPt -

recommendInitialPoint

public double recommendInitialPoint()

Enumerates equally spaced points in the interval and returns the point that has the function value closest to zero

Returns:

recommendInitialPoint

public double recommendInitialPoint(int nmax)

Enumerates nmax equally spaced points in the interval and returns the point that has the function value closest to zero

Parameters:

nmax -

Returns:

contains

public final boolean contains(double x)

Checks to see if the the supplied point is within the search interval

Parameters:

x -

Returns:

getLowerLimit

public final double getLowerLimit()

The lower limit for the search interval

Returns:

getUpperLimit

public final double getUpperLimit()

The upper limit for the search interval

Returns:

setInterval

public final void setInterval(FunctionIfc func,
                              Interval interval)

Sets the bracketing interval within which the root should be found. Throws IllegalArgumentExceptons if the lower limit is > upper limit and if the function does not cross the axis within the provided interval.

Parameters:

func -

interval -

setInterval

public final void setInterval(FunctionIfc func,
                              double xLower,
                              double xUpper)

Sets the bracketing interval within which the root should be found. Throws IllegalArgumentExceptons if the lower limit is > upper limit and if the function does not cross the axis within the provided interval.

Parameters:

func - Sets the function to be evaluated, must not be null

xLower -

xUpper -

toString

public java.lang.String toString()

Returns a String representation of the finder

Overrides:

toString in class IterativeProcess<RootFinderStep>

Returns:

A String with basic results

setFunction

protected void setFunction(FunctionIfc func)

Parameters:

func - OneVariableFunction

setRoot

protected void setRoot(double x)

hasConverged

public abstract boolean hasConverged()

Check to see if the result has been attained.

Returns:

boolean