Wrap and optimize FFTW. More...

#include <FFT.h>

Public Member Functions
bool	Backward (double *aRe_f)
	Performs the backward FFT of a frequency-domain purely real data vector. More...

bool	Backward (double aRe_f, double aIm_f)
	Performs the backward FFT of a frequency-domain complex data vector. More...

void	Backward (void)
	Performs the backward FFT. More...

bool	Forward (double *aRe_t)
	Performs the forward FFT of a time-domain purely real data vector. More...

bool	Forward (double aRe_t, double aIm_t)
	Performs the forward FFT of a time-domain complex data vector. More...

void	Forward (void)
	Performs the forward FFT. More...

double *	GetIm_f (const double aNorm=1.0)
	Returns the imaginary part of the frequency-domain data vector. More...

double	GetIm_f (const unsigned int aIndex)
	Returns the imaginary part of a frequency-domain data vector element. More...

double *	GetIm_t (const double aNorm=1.0)
	Returns the imaginary part of the time-domain data vector. More...

double	GetIm_t (const unsigned int aIndex)
	Returns the imaginary part of a time-domain data vector element. More...

double *	GetNorm2_f (const double aNorm=1.0)
	Returns the squared norm of the frequency-domain data vector. More...

double	GetNorm2_f (const unsigned int aIndex)
	Returns the squared norm of a frequency-domain data vector element. More...

double *	GetNorm2_t (const double aNorm=1.0)
	Returns the squared norm of the time-domain data vector. More...

double	GetNorm2_t (const unsigned int aIndex)
	Returns the squared norm of a time-domain data vector element. More...

double *	GetNorm_f (const double aNorm=1.0)
	Returns the norm of the frequency-domain data vector. More...

double	GetNorm_f (const unsigned int aIndex)
	Returns the norm of a frequency-domain data vector element. More...

double *	GetNorm_t (const double aNorm=1.0)
	Returns the norm of the time-domain data vector. More...

double	GetNorm_t (const unsigned int aIndex)
	Returns the norm of a time-domain data vector element. More...

double	GetPhase_f (const unsigned int aIndex)
	Returns the phase of a frequency-domain data vector element. More...

double *	GetPhase_f (void)
	Returns the phase of the frequency-domain data vector. More...

double	GetPhase_t (const unsigned int aIndex)
	Returns the phase of a time-domain data vector element. More...

double *	GetPhase_t (void)
	Returns the phase of the time-domain data vector. More...

double *	GetRe_f (const double aNorm=1.0)
	Returns the real part of the frequency-domain data vector. More...

double	GetRe_f (const unsigned int aIndex)
	Returns the real part of a frequency-domain data vector element. More...

double *	GetRe_t (const double aNorm=1.0)
	Returns the real part of the time-domain data vector. More...

double	GetRe_t (const unsigned int aIndex)
	Returns the real part of a time-domain data vector element. More...

unsigned int	GetSize_f (void)
	Returns the size of the frequency-domain vector. More...

unsigned int	GetSize_t (void)
	Returns the size of the time-domain vector. More...

void	SetIm_f (const unsigned int aIndex, const double aValue)
	Sets a frequency-domain vector element (imaginary part) to a given value. More...

void	SetIm_t (const unsigned int aIndex, const double aValue)
	Sets a time-domain vector element (imaginary part) to a given value. More...

void	SetRe_f (const unsigned int aIndex, const double aValue)
	Sets a frequency-domain vector element (real part) to a given value. More...

void	SetRe_t (const unsigned int aIndex, const double aValue)
	Sets a time-domain vector element (real part) to a given value. More...

Constructors and destructors
	fft (const unsigned int aSize_t, const string aPlan="FFTW_ESTIMATE", const string aType="c2c")
	Constructor of the fft class. More...

virtual	~fft (void)
	Destructor of the fft class. More...

Private Attributes
fftw_plan	FFT_Backward
	Backward plan. More...

fftw_plan	FFT_Forward
	Forward plan. More...

string	fPlan
	FFTW plan. More...

unsigned int	fSize_f
	Frequency-domain vector size. More...

unsigned int	fSize_t
	Time-domain vector size. More...

bool	fType
	FFT type true=c2c, false=r2c. More...

fftw_complex *	x_f
	Frequency-domain data. More...

fftw_complex *	xc_t
	Time-domain data - complex. More...

double *	xr_t
	Time-domain data - real. More...

Detailed Description

Wrap and optimize FFTW.

See also: FFTW.

Author: Florent Robinet

Constructor & Destructor Documentation

◆ fft()

fft::fft	(	const unsigned int	aSize_t,
		const string	aPlan = `"FFTW_ESTIMATE"`,
		const string	aType = `"c2c"`
	)

Constructor of the fft class.

A FFT plan is contructed for a given time-domain vector size. The input size must be an even number or else it will be forced as such.

A FFT type must be provided. The default "c2c" type provides a complex-to-complex FFT. In this case, the time-domain and the frequency domain vectors are both complex and have the same size. If a "r2c" type is selected, the time-domain vector is purely real. The frequency-domain vector is complex and its size is "aSize_t/2+1".

Warning: When using the "r2c" type, the backward transform will alter the frequency-domain vector. Do not use it after the transform.

Several FFTW plans are supported: "FFTW_ESTIMATE", "FFTW_MEASURE" and "FFTW_PATIENT".

Parameters

[in]	aSize_t	Time-domain vector size: must be an even number.
[in]	aPlan	FFT plan.
[in]	aType	FFT type "r2c" or "c2c".

◆ ~fft()

fft::~fft ( void )

virtual

Destructor of the fft class.

Member Function Documentation

◆ Backward() [1/3]

bool fft::Backward ( double * aRe_f )

Performs the backward FFT of a frequency-domain purely real data vector.

The input data vector is copied before being transformed.

Parameters

[in] aRe_f Frequency-domain real data vector.

◆ Backward() [2/3]

bool fft::Backward	(	double *	aRe_f,
		double *	aIm_f
	)

Performs the backward FFT of a frequency-domain complex data vector.

The input data vector is defined by 2 arrays for the real and imaginary parts. The input data vector is copied before being transformed.

Parameters

[in]	aRe_f	Frequency-domain data vector (real part).
[in]	aIm_f	Frequency-domain data vector (imaginary part).

Precondition: The input pointers must point to arrays the size of which must match the definition given in the constructor.

◆ Backward() [3/3]

void fft::Backward ( void )

inline

Performs the backward FFT.

◆ Forward() [1/3]

bool fft::Forward ( double * aRe_t )

Performs the forward FFT of a time-domain purely real data vector.

The input data vector is copied before being transformed.

Note: This function can be called both in a "c2c" and a "r2c" mode. In a "c2c" mode, the imaginary part is set to 0.

Parameters

[in] aRe_t Time-domain real data vector.

Precondition: The input pointer must point to an array the size of which must match the definition given in the constructor.

◆ Forward() [2/3]

bool fft::Forward	(	double *	aRe_t,
		double *	aIm_t
	)

Performs the forward FFT of a time-domain complex data vector.

The input data vector is defined by 2 arrays; the real and imaginary parts. The input data vector is copied before being transformed.

Note: This function can only be called in a "c2c" mode.

Returns: false if the "c2c" mode was not selected in the constructor; true if success.

Parameters

[in]	aRe_t	Time-domain data vector (real part).
[in]	aIm_t	Time-domain data vector (imaginary part).

Precondition: The input pointers must point to arrays the size of which must match the definition given in the constructor.

◆ Forward() [3/3]

void fft::Forward ( void )

inline

Performs the forward FFT.

◆ GetIm_f() [1/2]

double * fft::GetIm_f ( const double aNorm = 1.0 )

Returns the imaginary part of the frequency-domain data vector.

The user is in charge of deleting the returned array.

Parameters

[in] aNorm The returned vector is normalized by this parameter.

◆ GetIm_f() [2/2]

double fft::GetIm_f ( const unsigned int aIndex )

inline

Returns the imaginary part of a frequency-domain data vector element.

Parameters

[in] aIndex Vector index.

◆ GetIm_t() [1/2]

double * fft::GetIm_t ( const double aNorm = 1.0 )

Returns the imaginary part of the time-domain data vector.

The user is in charge of deleting the returned array.

Parameters

[in] aNorm The returned vector is normalized by this parameter.

◆ GetIm_t() [2/2]

double fft::GetIm_t ( const unsigned int aIndex )

inline

Returns the imaginary part of a time-domain data vector element.

Parameters

[in] aIndex vector index

◆ GetNorm2_f() [1/2]

double * fft::GetNorm2_f ( const double aNorm = 1.0 )

Returns the squared norm of the frequency-domain data vector.

The user is in charge of deleting the returned array.

Parameters

[in] aNorm The returned vector is normalized by this parameter.

◆ GetNorm2_f() [2/2]

double fft::GetNorm2_f ( const unsigned int aIndex )

inline

Returns the squared norm of a frequency-domain data vector element.

Parameters

[in] aIndex Vector index.

◆ GetNorm2_t() [1/2]

double * fft::GetNorm2_t ( const double aNorm = 1.0 )

Returns the squared norm of the time-domain data vector.

The user is in charge of deleting the returned array.

Parameters

[in] aNorm The returned vector is normalized by this parameter.

◆ GetNorm2_t() [2/2]

double fft::GetNorm2_t ( const unsigned int aIndex )

inline

Returns the squared norm of a time-domain data vector element.

Parameters

[in] aIndex Vector index.

◆ GetNorm_f() [1/2]

double * fft::GetNorm_f ( const double aNorm = 1.0 )

Returns the norm of the frequency-domain data vector.

The user is in charge of deleting the returned array.

Parameters

[in] aNorm The returned vector is normalized by this parameter.

◆ GetNorm_f() [2/2]

double fft::GetNorm_f ( const unsigned int aIndex )

inline

Returns the norm of a frequency-domain data vector element.

Parameters

[in] aIndex Vector index.

◆ GetNorm_t() [1/2]

double * fft::GetNorm_t ( const double aNorm = 1.0 )

Returns the norm of the time-domain data vector.

The user is in charge of deleting the returned array.

Parameters

[in] aNorm The returned vector is normalized by this parameter.

◆ GetNorm_t() [2/2]

double fft::GetNorm_t ( const unsigned int aIndex )

inline

Returns the norm of a time-domain data vector element.

Note: For "r2c", prefer the use of GetRe_t() (faster).

Parameters

[in] aIndex Vector index.

◆ GetPhase_f() [1/2]

double fft::GetPhase_f ( const unsigned int aIndex )

inline

Returns the phase of a frequency-domain data vector element.

The returned phase is between \(-\pi\) and \(-\pi\).

Parameters

[in] aIndex Vector index.

◆ GetPhase_f() [2/2]

double * fft::GetPhase_f ( void )

Returns the phase of the frequency-domain data vector.

The user is in charge of deleting the returned array.

◆ GetPhase_t() [1/2]

double fft::GetPhase_t ( const unsigned int aIndex )

inline

Returns the phase of a time-domain data vector element.

The returned phase is between \(-\pi\) and \(-\pi\).

Parameters

[in] aIndex vector index

◆ GetPhase_t() [2/2]

double * fft::GetPhase_t ( void )

Returns the phase of the time-domain data vector.

The user is in charge of deleting the returned array.

◆ GetRe_f() [1/2]

double * fft::GetRe_f ( const double aNorm = 1.0 )

Returns the real part of the frequency-domain data vector.

The user is in charge of deleting the returned array.

Parameters

[in] aNorm The returned vector is normalized by this parameter.

◆ GetRe_f() [2/2]

double fft::GetRe_f ( const unsigned int aIndex )

inline

Returns the real part of a frequency-domain data vector element.

Parameters

[in] aIndex Vector index.

◆ GetRe_t() [1/2]

double * fft::GetRe_t ( const double aNorm = 1.0 )

Returns the real part of the time-domain data vector.

The user is in charge of deleting the returned array.

Parameters

[in] aNorm The returned vector is normalized by this parameter.

◆ GetRe_t() [2/2]

double fft::GetRe_t ( const unsigned int aIndex )

inline

Returns the real part of a time-domain data vector element.

Parameters

[in] aIndex Vector index.

◆ GetSize_f()

unsigned int fft::GetSize_f ( void )

inline

Returns the size of the frequency-domain vector.

◆ GetSize_t()

unsigned int fft::GetSize_t ( void )

inline

Returns the size of the time-domain vector.

◆ SetIm_f()

void fft::SetIm_f	(	const unsigned int	aIndex,
		const double	aValue
	)

inline

Sets a frequency-domain vector element (imaginary part) to a given value.

Parameters

[in]	aIndex	Vector index.
[in]	aValue	New value.

◆ SetIm_t()

void fft::SetIm_t	(	const unsigned int	aIndex,
		const double	aValue
	)

inline

Sets a time-domain vector element (imaginary part) to a given value.

Parameters

[in]	aIndex	Vector index.
[in]	aValue	New value.

◆ SetRe_f()

void fft::SetRe_f	(	const unsigned int	aIndex,
		const double	aValue
	)

inline

Sets a frequency-domain vector element (real part) to a given value.

Parameters

[in]	aIndex	Vector index.
[in]	aValue	New value.

◆ SetRe_t()

void fft::SetRe_t	(	const unsigned int	aIndex,
		const double	aValue
	)

inline

Sets a time-domain vector element (real part) to a given value.

Parameters

[in]	aIndex	Vector index.
[in]	aValue	New value.

Member Data Documentation

◆ FFT_Backward

fftw_plan fft::FFT_Backward

private

Backward plan.

◆ FFT_Forward

fftw_plan fft::FFT_Forward

private

Forward plan.

◆ fPlan

string fft::fPlan

private

FFTW plan.

◆ fSize_f

unsigned int fft::fSize_f

private

Frequency-domain vector size.

◆ fSize_t

unsigned int fft::fSize_t

private

Time-domain vector size.

◆ fType

bool fft::fType

private

FFT type true=c2c, false=r2c.

◆ x_f

fftw_complex* fft::x_f

private

Frequency-domain data.

◆ xc_t

fftw_complex* fft::xc_t

private

Time-domain data - complex.

◆ xr_t

double* fft::xr_t

private

Time-domain data - real.

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

src/Utils/FFT.h
src/Utils/FFT.cc

Public Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ fft()

◆ ~fft()

Member Function Documentation

◆ Backward() [1/3]

◆ Backward() [2/3]

◆ Backward() [3/3]

◆ Forward() [1/3]

◆ Forward() [2/3]

◆ Forward() [3/3]

◆ GetIm_f() [1/2]

◆ GetIm_f() [2/2]

◆ GetIm_t() [1/2]

◆ GetIm_t() [2/2]

◆ GetNorm2_f() [1/2]

◆ GetNorm2_f() [2/2]

◆ GetNorm2_t() [1/2]

◆ GetNorm2_t() [2/2]

◆ GetNorm_f() [1/2]

◆ GetNorm_f() [2/2]

◆ GetNorm_t() [1/2]

◆ GetNorm_t() [2/2]

◆ GetPhase_f() [1/2]

◆ GetPhase_f() [2/2]

◆ GetPhase_t() [1/2]

◆ GetPhase_t() [2/2]

◆ GetRe_f() [1/2]

◆ GetRe_f() [2/2]

◆ GetRe_t() [1/2]

◆ GetRe_t() [2/2]

◆ GetSize_f()

◆ GetSize_t()

◆ SetIm_f()

◆ SetIm_t()

◆ SetRe_f()

◆ SetRe_t()

Member Data Documentation

◆ FFT_Backward

◆ FFT_Forward

◆ fPlan

◆ fSize_f

◆ fSize_t

◆ fType

◆ x_f

◆ xc_t

◆ xr_t