Fft Class Reference

Perform forward FFT's on real time data. Computes single-sided spectra, equivalent to Numpy's rfft and irfft functions. But then faster as it can use a fast FFT backend, such as FFTW. More...

#include <lasp_fft.h>

Public Member Functions
	Fft (const us nfft)
	Initialize FFT.
	~Fft ()
	Fft (const Fft &)=delete
Fft &	operator= (const Fft &)=delete
us	nfft () const
	Return nfft.
vc	fft (const vd &timedata)
cmat	fft (const dmat &timedata)
vd	ifft (const vc &freqdata)
dmat	ifft (const cmat &freqdata)

Static Public Member Functions
static void	load_fft_wisdom (const std::string &wisdom)
	Load FFT wisdom from a wisdom string. Function does nothing if FFT backend is not FFTW.
static std::string	store_fft_wisdom ()
	Return a string containing FFT wisdom storage. String is empty for backend != FFTW.

Detailed Description

Perform forward FFT's on real time data. Computes single-sided spectra, equivalent to Numpy's rfft and irfft functions. But then faster as it can use a fast FFT backend, such as FFTW.

Definition at line 24 of file lasp_fft.h.

Constructor & Destructor Documentation

Fft() [1/2]

Fft::Fft

(

const us

nfft

)

Initialize FFT.

Parameters

nfft	The length of nfft

Definition at line 108 of file lasp_fft.cpp.

~Fft()

Fft::~Fft

(

)

Definition at line 119 of file lasp_fft.cpp.

Fft() [2/2]

Fft::Fft ( const Fft &  )

delete

Member Function Documentation

fft() [1/2]

cmat Fft::fft

(

const dmat &

timedata

)

Compute the fft of the data matrix, first axis is assumed to be the time axis.

Parameters

[in]

timedata

Input time data, should have size nfft. First axis is time, second axis is channel

Returns

Result complex array

• WARNING *. This was source of a serious bug. It is not possible to run FFT's and IFFT's on the same _impl, as it overwrites the same memory. Uncommenting the line below results in faulty results.

Definition at line 131 of file lasp_fft.cpp.

fft() [2/2]

vc Fft::fft

(

const vd &

timedata

)

Compute the fft for a single channel of data.

Parameters

[in]

timedata

Input time data, should have size nfft

Returns

Result complex vector

Definition at line 126 of file lasp_fft.cpp.

ifft() [1/2]

dmat Fft::ifft

(

const cmat &

freqdata

)

Perform inverse FFT

Parameters

freqdata

Frequency domain data

Returns

timedata Time domain result

• WARNING *. This was source of a serious bug. It is not possible to run FFT's and IFFT's on the same _impl, as it overwrites the same memory. Uncommenting the line below results in faulty results.

Definition at line 150 of file lasp_fft.cpp.

ifft() [2/2]

vd Fft::ifft

(

const vc &

freqdata

)

Perform inverse fft on a single channel.

Parameters

[in]

freqdata

Frequency domain input data, to be iFft'th. Should have size nfft/2+1

Returns

timedata: iFft't data, size nfft.

Definition at line 145 of file lasp_fft.cpp.

load_fft_wisdom()

void Fft::load_fft_wisdom ( const std::string &  wisdom )

static

Load FFT wisdom from a wisdom string. Function does nothing if FFT backend is not FFTW.

Parameters

wisdom

Wisdom string content.

Definition at line 163 of file lasp_fft.cpp.

nfft()

us Fft::nfft

(

)

const

Return nfft.

Returns

nfft NFFT (lenght of the DFT transform)

Definition at line 121 of file lasp_fft.cpp.

operator=()

Fft & Fft::operator= ( const Fft &  )

delete

store_fft_wisdom()

std::string Fft::store_fft_wisdom ( )

static

Return a string containing FFT wisdom storage. String is empty for backend != FFTW.

Returns

FFT wisdom string

Definition at line 175 of file lasp_fft.cpp.

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

• src/lasp/dsp/lasp_fft.h
• src/lasp/dsp/lasp_fft.cpp