Package etomica.math.numerical

Class FastFourierTransform

java.lang.Object

etomica.math.numerical.FastFourierTransform

All Implemented Interfaces:

java.io.Serializable

public class FastFourierTransform
extends java.lang.Object
implements java.io.Serializable

This utility receives a set of data points, either Real, Imaginary or Both and performs a Discrete Fourier Transform on them using the Fast Fourier Transform algorithm. The class modifies the passed arrays directly, however they can use replicate copies instead using the BACKUP toggle. The class also maintains an array of the frequency indexes of the respective datum. This index can be used for graphing purposes (it would be the x axis, while the y axis is the real and/or imaginary transformed values.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
int	length

Constructor Summary

Constructors

Constructor	Description
FastFourierTransform()	Constructors accepting: nothing; all reals; both real and imaginary
FastFourierTransform(double[] dataReal)
FastFourierTransform(double[] dataReal, double[] dataImaginary)

Method Summary

Modifier and Type	Method	Description
double[]	getImaginary()
double[]	getReal()	array value calls
void	invert()	Reverse Transformation of discrete data sets
static void	main(java.lang.String[] arg)
static double	round(double x)
void	setData(double[] data)	For passing only one set of data - assumes passing all reals
void	setData(double[] data, boolean real)	For passing only all reals (true) or all imaginaries (false)
void	setData(double[] dataReal, double[] dataImaginary)	Saves the two passed arrays of doubles into this class, real and imaginary in order to transform.
void	transform()	Forward Transformation of discrete data sets

Methods inherited from class java.lang.Object

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

Field Detail

length

public int length

Constructor Detail

FastFourierTransform

public FastFourierTransform()

Constructors accepting: nothing; all reals; both real and imaginary

FastFourierTransform

public FastFourierTransform(double[] dataReal)

FastFourierTransform

public FastFourierTransform(double[] dataReal,
                            double[] dataImaginary)

Method Detail

setData

public void setData(double[] dataReal,
                    double[] dataImaginary)

Saves the two passed arrays of doubles into this class, real and imaginary in order to transform. Performs additional checks and indexes the array.

setData

public void setData(double[] data,
                    boolean real)

For passing only all reals (true) or all imaginaries (false)

setData

public void setData(double[] data)

For passing only one set of data - assumes passing all reals

transform

public void transform()

Forward Transformation of discrete data sets

invert

public void invert()

Reverse Transformation of discrete data sets

getReal

public double[] getReal()

array value calls

getImaginary

public double[] getImaginary()

main

public static void main(java.lang.String[] arg)

round

public static double round(double x)