## org.das2.qds.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.qds.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)
[search for examples] [view on GitHub] [view on old javadoc] [view source]

## backtransform

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

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

### Parameters

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

### Returns:

void (returns nothing)
[search for examples] [view on GitHub] [view on old javadoc] [view source]

## inverse

inverse( org.das2.qds.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)
[search for examples] [view on GitHub] [view on old javadoc] [view source]

## inverse

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

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

### Parameters

data - a ComplexArray.Double

### Returns:

void (returns nothing)
[search for examples] [view on GitHub] [view on old javadoc] [view source]

## normalization

normalization( ) → double

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

### Returns:

double
[search for examples] [view on GitHub] [view on old javadoc] [view source]

## toWraparoundOrder

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

### See Also:

[search for examples] [view on GitHub] [view on old javadoc] [view source]

## toWraparoundOrder

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

Return data in wraparound order.

### Parameters

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

### Returns:

double[]

### See Also:

[search for examples] [view on GitHub] [view on old javadoc] [view source]

## transform

transform( org.das2.qds.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)
[search for examples] [view on GitHub] [view on old javadoc] [view source]

## transform

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

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

### Parameters

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

### Returns:

void (returns nothing)
[search for examples] [view on GitHub] [view on old javadoc] [view source]