lti::fft Namespace Reference

Namespace with all FFT and inverse FFT routines based on code by Takuya Ooura with kind permission ooura@kurims.kyoto-u.ac.jp or ooura@mmm.t.u-tokyo.ac.jp). More...

Functions
template<class T >
T *	alloc_1d (const int &n1)
template<class T >
void	free_1d (T *i)
template<class T >
T **	alloc_2d (const int &n1, const int &n2)
template<class T >
void	free_2d (T **ii)
template<class T >
void	vrdft (int n, int isgn, vector< T > &a, int *ip, T *w)
template<class T >
void	rdft (int n, int isgn, T *a, int *ip, T *w)
template<class T >
void	cdft (int n, int isgn, T *a, int *ip, T *w)

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Detailed Description

Namespace with all FFT and inverse FFT routines based on code by Takuya Ooura with kind permission ooura@kurims.kyoto-u.ac.jp or ooura@mmm.t.u-tokyo.ac.jp).

The code has been adapted to use C++ and LTI-lib conventions. This functions will be used by the functors lti::realFFT and lti::realInvFFT

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Function Documentation

template<class T >

T* lti::fft::alloc_1d

(

const int &

n1

)

[inline]

reserve memory for a n-dimensional vector of elements with type T

Parameters:

n1

dimension of the vector

Returns:

pointer to the elements of the vector

template<class T >

T** lti::fft::alloc_2d	(	const int &	n1,
		const int &	n2
	)			[inline]

reserve memory for a n1xn2-matrix of elementes of type T

Parameters:

	n1	number of rows
	n2	number of columns

Returns:

pointer to the elements of the vector

template<class T >

void lti::fft::cdft	(	int	n,
		int	isgn,
		T *	a,
		int *	ip,
		T *	w
	)			[inline]

complex direct fourier transform

Parameters:

	n	data length (must be power of 2)
	isgn	transform direction: +1 for transform and -1 for inverse.
	a	the input/output data. In the frecuency domain the real parts will be stored in the even locations and the imaginary parts in the odd locations. a[1] = real[n/2]
	ip	work area for bit reversal. ip[0] and ip[1] are pointers to cos/sin table
	w	cos/sin table.

w[] and ip[] will be initialized if ip[0] == 0

template<class T >

void lti::fft::free_1d

(

T *

i

)

[inline]

free memory of 1d array of elements with type T

template<class T >

void lti::fft::free_2d

(

T **

ii

)

[inline]

free memory of 2d array of elements with type T

template<class T >

void lti::fft::rdft	(	int	n,
		int	isgn,
		T *	a,
		int *	ip,
		T *	w
	)			[inline]

real discrete fourier transform

Parameters:

	n	data length (must be power of 2)
	isgn	transform direction: +1 for transform and -1 for inverse.
	a	the input/output data. In the frecuency domain the real parts will be stored in the even locations and the imaginary parts in the odd locations. a[1] = real[n/2]
	ip	work area for bit reversal. ip[0] and ip[1] are pointers to cos/sin table
	w	cos/sin table.

w[] and ip[] will be initialized if ip[0] == 0

template<class T >

void lti::fft::vrdft	(	int	n,
		int	isgn,
		vector< T > &	a,
		int *	ip,
		T *	w
	)			[inline]

real discrete fourier transform for lti::vectors

Parameters:

	n	data length (must be power of 2)
	isgn	transform direction: +1 for transform and -1 for inverse.
	a	the input/output data. In the frecuency domain the real parts will be stored in the even locations and the imaginary parts in the odd locations. a[1] = real[n/2]
	ip	work area for bit reversal. ip[0] and ip[1] are pointers to cos/sin table
	w	cos/sin table. 3 w[] and ip[] will be initialized if ip[0] == 0