de.gsi.chart.renderer.datareduction

Class RamanDouglasPeukerDataReducer

java.lang.Object

de.gsi.chart.renderer.datareduction.RamanDouglasPeukerDataReducer

All Implemented Interfaces:

RendererDataReducer

public class RamanDouglasPeukerDataReducer
extends Object
implements RendererDataReducer

Filters data using Ramer-Douglas-Peucker algorithm with specified tolerance N.B. numberical complexity: average O(n log (n)) -> worst-case O(n^2)

Author:

Rzeźnik

See Also:

Ramer-Douglas-Peucker algorithm

Constructor Summary

Constructors

Constructor and Description
RamanDouglasPeukerDataReducer()

Method Summary

Modifier and Type	Method and Description
double[][]	filter(double[][] data)
double	getEpsilon()
protected double[][]	ramerDouglasPeuckerFunction(double[][] points, int startIndex, int endIndex)
int	reducePoints(double[] xValues, double[] yValues, double[] xPointErrorsPos, double[] xPointErrorsNeg, double[] yPointErrorsPos, double[] yPointErrorsNeg, String[] styles, boolean[] pointSelected, int indexMin, int indexMax) Internal function to the ErrorDataSetRenderer arrays are cached copies and operations are assumed to be performed in-place (<-> for performance reasons/minimisation of memory allocation)
void	setEpsilon(double epsilon)

Methods inherited from class java.lang.Object

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

Constructor Detail

RamanDouglasPeukerDataReducer

public RamanDouglasPeukerDataReducer()

Method Detail

filter

public double[][] filter(double[][] data)

getEpsilon

public double getEpsilon()

Returns:

epsilon

ramerDouglasPeuckerFunction

protected double[][] ramerDouglasPeuckerFunction(double[][] points,
                                                 int startIndex,
                                                 int endIndex)

reducePoints

public int reducePoints(double[] xValues,
                        double[] yValues,
                        double[] xPointErrorsPos,
                        double[] xPointErrorsNeg,
                        double[] yPointErrorsPos,
                        double[] yPointErrorsNeg,
                        String[] styles,
                        boolean[] pointSelected,
                        int indexMin,
                        int indexMax)

Description copied from interface: RendererDataReducer

Internal function to the ErrorDataSetRenderer arrays are cached copies and operations are assumed to be performed in-place (<-> for performance reasons/minimisation of memory allocation)

Specified by:

reducePoints in interface RendererDataReducer

Parameters:

xValues - array of x coordinates

yValues - array of y coordinates

xPointErrorsPos - array of coordinates containing x+exp

xPointErrorsNeg - array of coordinates containing x-exn

yPointErrorsPos - array of coordinates containing x+eyp

yPointErrorsNeg - array of coordinates containing x+eyn

styles - point styles

pointSelected - array containing the points that have been specially selected by the user

indexMin - minimum index of those array that shall be considered

indexMax - maximum index of those array that shall be considered

Returns:

effective number of points that remain after the reduction

setEpsilon

public void setEpsilon(double epsilon)

Parameters:

epsilon - maximum distance of a point in data between original curve and simplified curve