fft Class Reference

Wrap and optimize FFTW. More...

#include <FFT.h>

List of all members.

Public Member Functions
bool	Backward (double *aRe_f)
	FFT-backwards a frequency-domain real data vector.
bool	Backward (double *aRe_f, double *aIm_f)
	FFT-backwards a frequency-domain complex data vector.
void	Backward (void)
	FFT-backwards.
bool	Forward (double *aRe_t)
	FFT-forwards a time-domain real data vector.
bool	Forward (double *aRe_t, double *aIm_t)
	FFT-forwards a time-domain complex data vector.
void	Forward (void)
	FFT-forwards.
double *	GetIm_f (const double aNorm=1.0)
	Returns the imaginary part of the frequency-domain data vector.
double	GetIm_f (const int aIndex)
	Returns the imaginary part of a frequency-domain data vector element.
double *	GetIm_t (const double aNorm=1.0)
	Returns the imaginary part of the time-domain data vector.
double	GetIm_t (const int aIndex)
	Returns the imaginary part of a time-domain data vector element.
double *	GetNorm2_f (const double aNorm=1.0)
	Returns the squared norm of the frequency-domain data vector.
double	GetNorm2_f (const int aIndex)
	Returns the squared norm of a frequency-domain data vector element.
double *	GetNorm2_t (const double aNorm=1.0)
	Returns the squared norm of the time-domain data vector.
double	GetNorm2_t (const int aIndex)
	Returns the squared norm of a time-domain data vector element.
double *	GetNorm_f (const double aNorm=1.0)
	Returns the norm of the frequency-domain data vector.
double	GetNorm_f (const int aIndex)
	Returns the norm of a frequency-domain data vector element.
double *	GetNorm_t (const double aNorm=1.0)
	Returns the norm of the time-domain data vector.
double	GetNorm_t (const int aIndex)
	Returns the norm of a time-domain data vector element.
double *	GetPhase_f (void)
	Returns the phase of the frequency-domain data vector.
double	GetPhase_f (const int aIndex)
	Returns the phase of a frequency-domain data vector element.
double *	GetPhase_t (void)
	Returns the phase of the time-domain data vector.
double	GetPhase_t (const int aIndex)
	Returns the phase of a time-domain data vector element.
double *	GetRe_f (const double aNorm=1.0)
	Returns the real part of the frequency-domain data vector.
double	GetRe_f (const int aIndex)
	Returns the real part of a frequency-domain data vector element.
double *	GetRe_t (const double aNorm=1.0)
	Returns the real part of the time-domain data vector.
double	GetRe_t (const int aIndex)
	Returns the real part of a time-domain data vector element.
int	GetSize_f (void)
	Returns the size of the frequency-domain vector.
int	GetSize_t (void)
	Returns the size of the time-domain vector.
void	SetIm_f (const int aIndex, const double aValue)
	Sets a frequency-domain vector element (imaginary part) to a given value.
void	SetIm_t (const int aIndex, const double aValue)
	Sets a time-domain vector element (imaginary part) to a given value.
void	SetRe_f (const int aIndex, const double aValue)
	Sets a frequency-domain vector element (real part) to a given value.
void	SetRe_t (const int aIndex, const double aValue)
	Sets a time-domain vector element (real part) to a given value.
Constructors and destructors
	fft (const int aSize_t, const string aPlan="FFTW_ESTIMATE", const string aType="c2c")
	Constructor of the fft class.
virtual	~fft (void)
	Destructor of the fft class.

---

Detailed Description

Wrap and optimize FFTW.

See FFTW.

Author:

Florent Robinet

---

Constructor & Destructor Documentation

fft::fft	(	const 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 input 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".

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

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

Parameters:

	aSize_t	time-domain vector size: must be even
	aPlan	FFT plan
	aType	FFT type "r2c" or "c2c"

fft::~fft

(

void

)

[virtual]

Destructor of the fft class.

---

Member Function Documentation

bool fft::Backward

(

double *

aRe_f

)

FFT-backwards a frequency-domain real data vector.

The input data vector is copied before being transformed. It must verify the size defined in the constructor.

Parameters:

aRe_f

frequency-domain real data vector

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

FFT-backwards 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. It must verify the size defined in the constructor.

Parameters:

	aRe_f	frequency-domain data vector (real part)
	aIm_f	frequency-domain data vector (imaginary part)

void fft::Backward

(

void

)

[inline]

FFT-backwards.

bool fft::Forward

(

double *

aRe_t

)

FFT-forwards a time-domain real data vector.

The input data vector is copied before being transformed. It must verify the size defined in the constructor.

Parameters:

aRe_t

time-domain real data vector

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

FFT-forwards a time-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. It must verify the size defined in the constructor. This function can only be called in a "c2c" mode.

Parameters:

	aRe_t	time-domain data vector (real part)
	aIm_t	time-domain data vector (imaginary part)

void fft::Forward

(

void

)

[inline]

FFT-forwards.

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:

aNorm

the returned vector is normalized by this parameter

double fft::GetIm_f

(

const int

aIndex

)

[inline]

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

Parameters:

aIndex

vector index

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:

aNorm

the returned vector is normalized by this parameter

double fft::GetIm_t

(

const int

aIndex

)

[inline]

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

Parameters:

aIndex

vector index

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:

aNorm

the returned vector is normalized by this parameter

double fft::GetNorm2_f

(

const int

aIndex

)

[inline]

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

Parameters:

aIndex

vector index

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:

aNorm

the returned vector is normalized by this parameter

double fft::GetNorm2_t

(

const int

aIndex

)

[inline]

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

Parameters:

aIndex

vector index

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:

aNorm

the returned vector is normalized by this parameter

double fft::GetNorm_f

(

const int

aIndex

)

[inline]

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

Parameters:

aIndex

vector index

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:

aNorm

the returned vector is normalized by this parameter

double fft::GetNorm_t

(

const int

aIndex

)

[inline]

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

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

Parameters:

aIndex

vector index

double * fft::GetPhase_f

(

void

)

Returns the phase of the frequency-domain data vector.

The user is in charge of deleting the returned array.

double fft::GetPhase_f

(

const int

aIndex

)

[inline]

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

Parameters:

aIndex

vector index

double * fft::GetPhase_t

(

void

)

Returns the phase of the time-domain data vector.

The user is in charge of deleting the returned array.

double fft::GetPhase_t

(

const int

aIndex

)

[inline]

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

Parameters:

aIndex

vector index

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:

aNorm

the returned vector is normalized by this parameter

double fft::GetRe_f

(

const int

aIndex

)

[inline]

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

Parameters:

aIndex

vector index

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:

aNorm

the returned vector is normalized by this parameter

double fft::GetRe_t

(

const int

aIndex

)

[inline]

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

Parameters:

aIndex

vector index

int fft::GetSize_f

(

void

)

[inline]

Returns the size of the frequency-domain vector.

int fft::GetSize_t

(

void

)

[inline]

Returns the size of the time-domain vector.

void fft::SetIm_f	(	const int	aIndex,
		const double	aValue
	)			[inline]

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

Parameters:

	aIndex	vector index
	aValue	new value

void fft::SetIm_t	(	const int	aIndex,
		const double	aValue
	)			[inline]

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

Parameters:

	aIndex	vector index
	aValue	new value

void fft::SetRe_f	(	const int	aIndex,
		const double	aValue
	)			[inline]

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

Parameters:

	aIndex	vector index
	aValue	new value

void fft::SetRe_t	(	const int	aIndex,
		const double	aValue
	)			[inline]

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

Parameters:

	aIndex	vector index
	aValue	new value

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

• /afs/in2p3.fr/throng/virgo/virgoDev/SoftFlorent/GWOLLUM/v2r2/src/Utils/FFT.h
• /afs/in2p3.fr/throng/virgo/virgoDev/SoftFlorent/GWOLLUM/v2r2/src/Utils/FFT.cc