org.das2.qds.math.fft

Class GeneralFFT

java.lang.Object

org.das2.qds.math.fft.GeneralFFT

public class GeneralFFT
extends java.lang.Object

Provides forward and reverse FFT methods for any number of elements. The FFTs are implemented using a modified version of the jnt.FFT package from NIST. This version operates on ComplexArray objects that may be backed by das2 data sets avoiding unnecessary copies.

Constructor Summary

Constructors

Constructor and Description
GeneralFFT(int n, boolean doublePrecision, boolean real) Initialize the FFT object by constructing wave tables that can be repeatly used.

Method Summary

Modifier and Type	Method and Description
void	invTransform(ComplexArray.Double data) perform the inverse transform on the array in situ.
void	invTransform(ComplexArray.Float data) perform the inverse transform on the array in situ.
static GeneralFFT	newDoubleFFT(int n) creates an FFT object that operates on a ComplexArray.Double of n elements.
static GeneralFFT	newFloatFFT(int n) creates an FFT object that operates on a ComplexArray.Float of n elements.
int	size() return the number of points in the fft.
void	transform(ComplexArray.Double data) perform the forward transform on the array in situ.
void	transform(ComplexArray.Float data) perform the forward transform on the array in situ.

Methods inherited from class java.lang.Object

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

Constructor Detail

GeneralFFT

public GeneralFFT(int n,
                  boolean doublePrecision,
                  boolean real)

Initialize the FFT object by constructing wave tables that can be repeatly used.

Method Detail

newFloatFFT

public static GeneralFFT newFloatFFT(int n)

creates an FFT object that operates on a ComplexArray.Float of n elements.

newDoubleFFT

public static GeneralFFT newDoubleFFT(int n)

creates an FFT object that operates on a ComplexArray.Double of n elements.

transform

public void transform(ComplexArray.Double data)

perform the forward transform on the array in situ.

transform

public void transform(ComplexArray.Float data)

perform the forward transform on the array in situ.

invTransform

public void invTransform(ComplexArray.Double data)

perform the inverse transform on the array in situ.

invTransform

public void invTransform(ComplexArray.Float data)

perform the inverse transform on the array in situ.

size

public int size()

return the number of points in the fft.

Returns:

the number of points in the fft.