PowerSpectrumGetter Class Reference

Much faster that FFT.h's PowerSpectrum, at least in Short-Time Fourier Transform-like situations, where many power spectra of the same size are needed. Currently only power spectrum, but may be generalized to other uses. More...

#include <PowerSpectrumGetter.h>

Collaboration diagram for PowerSpectrumGetter:

Public Member Functions
	PowerSpectrumGetter (int fftSize)
	~PowerSpectrumGetter ()
void	operator() (PffftFloats alignedBuffer, PffftFloats alignedOutput)
	Computes the power spectrum of buffer into output. More...

Private Attributes
const int	mFftSize
PffftSetupHolder	mSetup
PffftFloatVector	mWork

Detailed Description

Much faster that FFT.h's PowerSpectrum, at least in Short-Time Fourier Transform-like situations, where many power spectra of the same size are needed. Currently only power spectrum, but may be generalized to other uses.

Definition at line 208 of file PowerSpectrumGetter.h.

Constructor & Destructor Documentation

PowerSpectrumGetter()

PowerSpectrumGetter::PowerSpectrumGetter ( int  fftSize )

explicit

Definition at line 41 of file PowerSpectrumGetter.cpp.

    : mFftSize { fftSize }
    , mSetup { pffft_new_setup(fftSize, PFFFT_REAL) }
    , mWork(fftSize)
{
}

~PowerSpectrumGetter()

PowerSpectrumGetter::~PowerSpectrumGetter

(

)

Definition at line 48 of file PowerSpectrumGetter.cpp.

{
}

Member Function Documentation

operator()()

void PowerSpectrumGetter::operator()	(	PffftFloats	alignedBuffer,
		PffftFloats	alignedOutput
	)

Computes the power spectrum of buffer into output.

Parameters

buffer	Input samples of size fftSize. Also gets used as placeholder and gets overwritten, so copy your data elsewhere if you need it again afterwards.
output	fftSize / 2 + 1 samples.

Definition at line 52 of file PowerSpectrumGetter.cpp.

{
   const auto buffer = alignedBuffer.get();
   const auto output = alignedOutput.get();
   pffft_transform_ordered(mSetup.get(),
      buffer, buffer, mWork.data(), PFFFT_FORWARD);
   output[0] = buffer[0] * buffer[0];
   for (auto i = 1; i < mFftSize / 2; ++i)
      output[i] =
         buffer[i * 2] * buffer[i * 2] + buffer[i * 2 + 1] * buffer[i * 2 + 1];
   output[mFftSize / 2] = buffer[1] * buffer[1];
}

References PffftFloats::get(), mFftSize, mSetup, and mWork.

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Member Data Documentation

mFftSize

const int PowerSpectrumGetter::mFftSize

private

Definition at line 224 of file PowerSpectrumGetter.h.

Referenced by operator()().

mSetup

PffftSetupHolder PowerSpectrumGetter::mSetup

private

Definition at line 225 of file PowerSpectrumGetter.h.

Referenced by operator()().

mWork

PffftFloatVector PowerSpectrumGetter::mWork

private

Definition at line 226 of file PowerSpectrumGetter.h.

Referenced by operator()().

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The documentation for this class was generated from the following files:

• PowerSpectrumGetter.h
• PowerSpectrumGetter.cpp