org.das2.math.fft.jnt

Class RealDoubleFFT_Even

java.lang.Object

org.das2.math.fft.jnt.RealDoubleFFT

org.das2.math.fft.jnt.RealDoubleFFT_Even

public class RealDoubleFFT_Even
extends RealDoubleFFT

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

Constructor Summary

Constructors

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

Method Summary

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

Methods inherited from class org.das2.math.fft.jnt.RealDoubleFFT

checkData

Methods inherited from class java.lang.Object

clone, equals, finalize, 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(ComplexArray.Double data)

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

Overrides:

transform in class RealDoubleFFT

toWraparoundOrder

public ComplexArray.Double toWraparoundOrder(ComplexArray.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.

See Also:

wraparound format

toWraparoundOrder

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

Return data in wraparound order.

See Also:

wraparound format

backtransform

public void backtransform(ComplexArray.Double data)

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

Overrides:

backtransform in class RealDoubleFFT

transform

public void transform(ComplexArray.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(ComplexArray.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(ComplexArray.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(ComplexArray.Double data)

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

Overrides:

inverse in class RealDoubleFFT