vec_math
Interface Differentiator

All Known Implementing Classes:

SimpleDifferentiator

public interface Differentiator

This interface defines calculus of a differentiator. It may be used in different ways. Either you can set a list of x/y values using the setData(double[], double[]) method, or you can add values during the life-time of the differentiator using the add(double, double) method. Calling getDerivative() returns the first derivative at the cusp of the data points, i.e. at the highest x-value.
For performance issues, the differentiator uses primitive data types instead of Double objects.

Method Summary

void	add(double y) Adds a new point to the data set, stating only a y value for an equally-spaced data set.
void	add(double x, double y) Adds a new point to the data set, stating both, the x and y value.
double	getDerivative() Calculates the first derivative at the highest x-value or at the most recently added y-value in equal-sized data sets.
double	getDerivative(double x) Calculates the first derivative at the stated x-value.
void	setData(double[] y) Sets an equally-spaced y-data set.
void	setData(double[] x, double[] y) Sets an entire list of x/y data points.

Method Detail

setData

void setData(double[] x,
             double[] y)

Sets an entire list of x/y data points. If the x-list is null, y is expected to be an equally-spaced data set. Note that not necessarily all differntiator must implement both, methods, i.e. the equally-spaced and the x/y independently settable. It is mandatory that the x-array is sorted for ascending x-values.

Parameters:

x - A double-array representing the x-axis values.

y - A double-array representing the y-axis values.

setData

void setData(double[] y)

Sets an equally-spaced y-data set. Differentiation here assumes a step-size in x equal to one. Note that not necessarily all differntiator must implement both, methods, i.e. the equally-spaced and the x/y independently settable.

Parameters:

y - A double-array representing the y-axis values.

add

void add(double x,
         double y)

Adds a new point to the data set, stating both, the x and y value. The newly added x-value must be higher than any previously added or set x-value. Note that not necessarily all differntiator must implement both, methods, i.e. the equally-spaced and the x/y independently settable.

Parameters:

x - A newly added x-value.

y - A newly added y-value.

add

void add(double y)

Adds a new point to the data set, stating only a y value for an equally-spaced data set. Note that not necessarily all differntiator must implement both, methods, i.e. the equally-spaced and the x/y independently settable.

Parameters:

y - A newly added y-value.

getDerivative

double getDerivative()

Calculates the first derivative at the highest x-value or at the most recently added y-value in equal-sized data sets. Note that not necessarily all differntiator must implement both derivative methods.

getDerivative

double getDerivative(double x)

Calculates the first derivative at the stated x-value. Note that not necessarily all differntiator must implement both derivative methods.