jahuwaldt.tools.math

Class AbstractEvaluatable1D

java.lang.Object

jahuwaldt.tools.math.AbstractEvaluatable1D

All Implemented Interfaces:

Evaluatable1D

public abstract class AbstractEvaluatable1D
extends java.lang.Object
implements Evaluatable1D

A class that defines a 1D function y = fn(x) (named "function") that can be called by math tools such as root finders. Also defines the derivative of the function. dy/dx = d fn(x)/dx (oddly enough, named "derivative"). An optional capability of setting an initial function value is also provided. This aides the calculating of some functions and is a common enough problem that I've included it in the basic Evaluatable1D class definition.

Modified by: Joseph A. Huwaldt

Version:

September 16, 2012

Author:

Joseph A. Huwaldt Date: October 7, 1998

Constructor Summary

Constructors

Constructor and Description
AbstractEvaluatable1D()

Method Summary

Modifier and Type	Method and Description
double	derivative(double x) Calculates the derivative of the function dy/dx = d fn(x)/dx.
double	getInitialValue() Returns the initial function value set with "setInitialValue()".
void	setInitialValue(double initialValue) Used to set an initial function value (or any other initial value the user wants to use).

Methods inherited from class java.lang.Object

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

Methods inherited from interface jahuwaldt.tools.math.Evaluatable1D

function

Constructor Detail

AbstractEvaluatable1D

public AbstractEvaluatable1D()

Method Detail

derivative

public double derivative(double x)
                  throws RootException

Calculates the derivative of the function dy/dx = d fn(x)/dx. Classes wanting to return the derivative of the function at x should override this function. If the method using this class doesn't require the derivative, do nothing and Double.NaN is returned.

Specified by:

derivative in interface Evaluatable1D

Parameters:

x - Independent parameter to the function.

Returns:

The function value at x or Double.NaN if the derivative is not defined.

Throws:

RootException

setInitialValue

public void setInitialValue(double initialValue)

Used to set an initial function value (or any other initial value the user wants to use). This function is provided as an optional service. The programmer may use this to aide in solving problems where you want to find the point where f(x) - f0 = 0. Use this function to set f0 and use "getInitialValue()" to retrieve f0 and calculate f(x) - f0 in your "function()" definition.

Parameters:

initialValue - Initial function value, f0.

getInitialValue

public final double getInitialValue()

Returns the initial function value set with "setInitialValue()".

Returns:

The initial value set with "setInitialValue()".