Package jahuwaldt.tools.math

Class 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 = dfn(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:
    February 23, 2025
    Author:
    Joseph A. Huwaldt Date: October 7, 1998

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method 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

    • 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 - if there is any problem calculating the derivative.

      • 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()".