math.fourierTransforms.interleaved
Class RealDoubleFFT_Even

java.lang.Object
  math.fourierTransforms.interleaved.RealDoubleFFT
      math.fourierTransforms.interleaved.RealDoubleFFT_Even

public class RealDoubleFFT_Even
extends RealDoubleFFT

Computes FFT's of real, double precision data when n is even, by computing complex FFT.

Author:

Bruce R. Miller bruce.miller@nist.gov, Derived from Numerical Methods., Contribution of the National Institute of Standards and Technology,, not subject to copyright.

Constructor Summary

RealDoubleFFT_Even(int n)
Create an FFT for transforming n points of real, double precision data.

Method Summary

void	backtransform(double[] data) Compute the (unnomalized) inverse FFT of data, leaving it in place.
void	backtransform(double[] data, int i0, int stride) Compute the (unnomalized) inverse FFT of data, leaving it in place.
void	inverse(double[] data) Compute the (nomalized) inverse FFT of data, leaving it in place.
void	inverse(double[] data, int i0, int stride) Compute the (nomalized) inverse FFT of data, leaving it in place.
double	normalization() Return the normalization factor.
double[]	toWraparoundOrder(double[] data) Return data in wraparound order.
double[]	toWraparoundOrder(double[] data, int i0, int stride) Return data in wraparound order.
void	transform(double[] data) Compute the Fast Fourier Transform of data leaving the result in data.
void	transform(double[] data, int i0, int stride) Compute the Fast Fourier Transform of data leaving the result in data.

Methods inherited from class java.lang.Object

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

Constructor Detail

RealDoubleFFT_Even

public RealDoubleFFT_Even(int n)

Create an FFT for transforming n points of real, double precision data.

Method Detail

transform

public void transform(double[] data)

Compute the Fast Fourier Transform of data leaving the result in data.

Overrides:

transform in class RealDoubleFFT

toWraparoundOrder

public double[] toWraparoundOrder(double[] data)

Return data in wraparound order. i0 and stride are used to traverse data; the new array is in packed (i0=0, stride=1) format.

Specified by:

toWraparoundOrder in class RealDoubleFFT

See Also:

wraparound format

toWraparoundOrder

public double[] toWraparoundOrder(double[] data,
                                  int i0,
                                  int stride)

Return data in wraparound order.

Specified by:

toWraparoundOrder in class RealDoubleFFT

See Also:

wraparound format

backtransform

public void backtransform(double[] data)

Compute the (unnomalized) inverse FFT of data, leaving it in place.

Overrides:

backtransform in class RealDoubleFFT

transform

public void transform(double[] data,
                      int i0,
                      int stride)

Compute the Fast Fourier Transform of data leaving the result in data.

Specified by:

transform in class RealDoubleFFT

backtransform

public void backtransform(double[] data,
                          int i0,
                          int stride)

Compute the (unnomalized) inverse FFT of data, leaving it in place.

Specified by:

backtransform in class RealDoubleFFT

inverse

public void inverse(double[] data,
                    int i0,
                    int stride)

Compute the (nomalized) inverse FFT of data, leaving it in place.

Overrides:

inverse in class RealDoubleFFT

normalization

public double normalization()

Return the normalization factor. Multiply the elements of the backtransform'ed data to get the normalized inverse.

Overrides:

normalization in class RealDoubleFFT

inverse

public void inverse(double[] data)

Compute the (nomalized) inverse FFT of data, leaving it in place.

Overrides:

inverse in class RealDoubleFFT