org.das2.math.fft.jnt.RealDoubleFFT_Even

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

RealDoubleFFT_Even( int n )

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

backtransform

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

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

Parameters

data - a ComplexArray.Double

Returns:

void (returns nothing)

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backtransform( org.das2.math.fft.ComplexArray.Double data, int i0, int stride ) → void

inverse

inverse( org.das2.math.fft.ComplexArray.Double data, int i0, int stride ) → void

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

Parameters

data - a ComplexArray.Double
i0 - an int
stride - an int

Returns:

void (returns nothing)

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

normalization

normalization( ) → double

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

Returns:

double

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toWraparoundOrder

toWraparoundOrder( org.das2.math.fft.ComplexArray.Double data ) → org.das2.math.fft.ComplexArray.Double

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

Parameters

data - a ComplexArray.Double

Returns:

org.das2.math.fft.ComplexArray.Double

See Also:

wraparound format


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toWraparoundOrder( org.das2.math.fft.ComplexArray.Double data, int i0, int stride ) → double[]

transform

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

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

Parameters

data - a ComplexArray.Double

Returns:

void (returns nothing)

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transform( org.das2.math.fft.ComplexArray.Double data, int i0, int stride ) → void