rack::dsp::RealFFT Struct Reference

Real-valued FFT context. More...

#include <fft.hpp>

Public Member Functions
	RealFFT (size_t length)
	~RealFFT ()
void	rfftUnordered (const float *input, float *output)
	Performs the real FFT.
void	irfftUnordered (const float *input, float *output)
	Performs the inverse real FFT.
void	rfft (const float *input, float *output)
	Slower than the above methods, but returns results in the "canonical" FFT order as follows.
void	irfft (const float *input, float *output)
void	scale (float *x)
	Scales the RFFT so that scale(IFFT(FFT(x))) = x.

Public Attributes
PFFFT_Setup *	setup
int	length

Detailed Description

Real-valued FFT context.

Wrapper for PFFFT length must be a multiple of 32. Buffers must be aligned to 16-byte boundaries. new[] and malloc() do this for you.

Constructor & Destructor Documentation

RealFFT()

rack::dsp::RealFFT::RealFFT ( size_t length )

inline

~RealFFT()

rack::dsp::RealFFT::~RealFFT ( )

inline

Member Function Documentation

rfftUnordered()

void rack::dsp::RealFFT::rfftUnordered ( const float * input, float * output )

inline

Performs the real FFT.

Input and output must be aligned using the above align*() functions. Input and output arrays may overlap. Input is length elements. Output is 2*length elements. Output is arbitrarily ordered for performance reasons. However, this ordering is consistent, so element-wise multiplication with line up with other results, and the inverse FFT will return a correctly ordered result.

irfftUnordered()

void rack::dsp::RealFFT::irfftUnordered ( const float * input, float * output )

inline

Performs the inverse real FFT.

Input is 2*length elements. Output is length elements. Scaling is such that IRFFT(RFFT(x)) = N*x.

rfft()

void rack::dsp::RealFFT::rfft ( const float * input, float * output )

inline

Slower than the above methods, but returns results in the "canonical" FFT order as follows.

output[0] = F(0) output[1] = F(n/2) output[2] = real(F(1)) output[3] = imag(F(1)) output[4] = real(F(2)) output[5] = imag(F(2)) ... output[length - 2] = real(F(n/2 - 1)) output[length - 1] = imag(F(n/2 - 1))

irfft()

void rack::dsp::RealFFT::irfft ( const float * input, float * output )

inline

scale()

void rack::dsp::RealFFT::scale ( float * x )

inline

Scales the RFFT so that scale(IFFT(FFT(x))) = x.

Member Data Documentation

setup

PFFFT_Setup* rack::dsp::RealFFT::setup

length

int rack::dsp::RealFFT::length

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The documentation for this struct was generated from the following file:

• /home/vortico/src/vcv/Rack2/include/dsp/fft.hpp