spectra Namespace Reference

A namespace providing wrappers for FFTW library. More...

Functions
std::vector< double >	abs (std::vector< fftw_complex > vals)
	Compute the magnitute. More...
std::vector< double >	abs2 (std::vector< fftw_complex > vals)
	Compute the magnitute squared. More...
std::vector< double >	arg (std::vector< fftw_complex > vals)
	Compute the phase in radiants. More...
std::vector< double >	argd (std::vector< fftw_complex > vals)
	Compute the phase in degrees. More...
void	polar (std::vector< fftw_complex > vals, std::vector< double > *mag, std::vector< double > *phase)
	Compute the polar coordinates. More...
void	polard (std::vector< fftw_complex > vals, std::vector< double > *mag, std::vector< double > *phase)
	Compute the polar coordinates. More...
void	bode (std::vector< fftw_complex > vals, std::vector< double > *mag, std::vector< double > *phase)
	Compute the bode coordinates. More...
void	boded (std::vector< fftw_complex > vals, std::vector< double > *mag, std::vector< double > *phase)
	Compute the bode coordinates. More...
std::vector< double >	frequency (size_t size, double fmax=0.5)
	Compute the frequency vector. More...
std::vector< fftw_complex >	fft (std::vector< double > vals)
	Compute the spectra. More...
std::vector< double >	psd (std::vector< double > vals)
	Compute the power-spectra-density. More...

Variables
constexpr int	REAL = 0
	Position of the real part in fftw_complex type. More...
constexpr int	IMAG = 1
	Position of the imag part in fftw_complex type. More...

Detailed Description

A namespace providing wrappers for FFTW library.

Namespace providing wrapper function and utilities for spectral analysis using the FFTW library and the std::vector library.

Author

Stefano Lovato

Date

2022

Function Documentation

abs()

std::vector< double > spectra::abs

(

std::vector< fftw_complex >

vals

)

Compute the magnitute.

Function to compute the magnitude of a complex vector.

Parameters

vals	A std::vector<fftw_complex> used to compute the magnitude.

Returns

A std::vector<double> containing the maginutude.

abs2()

std::vector< double > spectra::abs2

(

std::vector< fftw_complex >

vals

)

Compute the magnitute squared.

Function to compute the magnitude of a complex vector.

Parameters

vals	A std::vector<fftw_complex> used to compute the magnitude squared.

Returns

A std::vector<double> containing the maginutude squared.

arg()

std::vector< double > spectra::arg

(

std::vector< fftw_complex >

vals

)

Compute the phase in radiants.

Function to compute the phase in radiants of a complex vector.

Parameters

vals	A std::vector<fftw_complex> used to compute the phase.

Returns

A std::vector<double> containing the phase in radiants.

argd()

std::vector< double > spectra::argd

(

std::vector< fftw_complex >

vals

)

Compute the phase in degrees.

Function to compute the phase in degrees of a complex vector.

Parameters

vals	A std::vector<fftw_complex> used to compute the phase.

Returns

A std::vector<double> containing the phase in degrees.

bode()

void spectra::bode	(	std::vector< fftw_complex >	vals,
		std::vector< double > *	mag,
		std::vector< double > *	phase
	)

Compute the bode coordinates.

Function to compute the bode coordinates (decibel and phase in radians) of a complex vector.

Parameters

vals	A std::vector<fftw_complex> used to compute the phase.
mag	A pointer to a std::vector<double> to store the computed decibel.
phase	A pointer to a std::vector<double> to store the computed phase (in radians).

boded()

void spectra::boded	(	std::vector< fftw_complex >	vals,
		std::vector< double > *	mag,
		std::vector< double > *	phase
	)

Compute the bode coordinates.

Function to compute the bode coordinates (decibel and phase in degrees) of a complex vector.

Parameters

vals	A std::vector<fftw_complex> used to compute the phase.
mag	A pointer to a std::vector<double> to store the computed decibel.
phase	A pointer to a std::vector<double> to store the computed phase (in degrees).

fft()

std::vector< fftw_complex > spectra::fft

(

std::vector< double >

vals

)

Compute the spectra.

Function to compute the complex spectra of a real signal using the discrete-fourier-transform with the FFTW library.

Parameters

vals	A std::vector<double> containing the values of the signal.

Returns

A std::vector<fftw_complex> containing the complex spectra of the signal.

frequency()

std::vector< double > spectra::frequency	(	size_t	size,
		double	fmax = 0.5
	)

Compute the frequency vector.

Function to compute the frequency vector with given size and maximum frequency.

Parameters

size	The size of the resulting vector.
fmax	The maximum frequency.

Returns

A std::vector<double> containing size frequency from 0 to fmax.

polar()

void spectra::polar	(	std::vector< fftw_complex >	vals,
		std::vector< double > *	mag,
		std::vector< double > *	phase
	)

Compute the polar coordinates.

Function to compute the polar coordinates (magnitude and phase in radians) of a complex vector.

Parameters

vals	A std::vector<fftw_complex> used to compute the phase.
mag	A pointer to a std::vector<double> to store the computed magnitude.
phase	A pointer to a std::vector<double> to store the computed phase (in radians).

polard()

void spectra::polard	(	std::vector< fftw_complex >	vals,
		std::vector< double > *	mag,
		std::vector< double > *	phase
	)

Compute the polar coordinates.

Function to compute the polar coordinates (magnitude and phase in degrees) of a complex vector.

Parameters

vals	A std::vector<fftw_complex> used to compute the phase.
mag	A pointer to a std::vector<double> to store the computed magnitude.
phase	A pointer to a std::vector<double> to store the computed phase (in degrees).

psd()

std::vector< double > spectra::psd

(

std::vector< double >

vals

)

Compute the power-spectra-density.

Function to compute the power-spectra-density of a real signal using the discrete-fourier-transform with the FFTW library.

Parameters

vals	A std::vector<double> containing the values of the signal.

Returns

A A std::vector<double> containing the power-spectra-density of the signal.

Variable Documentation

IMAG

constexpr int spectra::IMAG = 1

constexpr

Position of the imag part in fftw_complex type.

REAL

constexpr int spectra::REAL = 0

constexpr

Position of the real part in fftw_complex type.