org.das2.math.fft.GeneralFFT

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.

GeneralFFT( int n, boolean doublePrecision, boolean real )

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

invTransform

invTransform( org.das2.math.fft.ComplexArray.Double data ) → void

perform the inverse transform on the array in situ.

Parameters

data - a ComplexArray.Double

Returns:

void (returns nothing)

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invTransform( org.das2.math.fft.ComplexArray.Float data ) → void

newDoubleFFT

newDoubleFFT( int n ) → org.das2.math.fft.GeneralFFT

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

Parameters

n - an int

Returns:

org.das2.math.fft.GeneralFFT

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newFloatFFT

newFloatFFT( int n ) → org.das2.math.fft.GeneralFFT

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

Parameters

n - an int

Returns:

org.das2.math.fft.GeneralFFT

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size

size( ) → int

return the number of points in the fft.

Returns:

an int

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transform

transform( org.das2.math.fft.ComplexArray.Double data ) → void

perform the forward transform on the array in situ.

Parameters

data - a ComplexArray.Double

Returns:

void (returns nothing)

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transform( org.das2.math.fft.ComplexArray.Float data ) → void