Data Structures
class	spFFTRec
	A class to handle FFT execution. More...

Macros
#define	spFFTSpeed spComputeSpeed

#define	SP_FFT_HIGHEST_PRECISION SP_HIGHEST_PRECISION

#define	SP_FFT_HIGH_DOUBLE_PRECISION SP_HIGH_DOUBLE_PRECISION

#define	SP_FFT_DOUBLE_PRECISION SP_DOUBLE_PRECISION

#define	SP_FFT_LOW_DOUBLE_PRECISION SP_LOW_DOUBLE_PRECISION

#define	SP_FFT_HIGH_FLOAT_PRECISION SP_HIGH_FLOAT_PRECISION

#define	SP_FFT_FLOAT_PRECISION SP_FLOAT_PRECISION

#define	SP_FFT_LOW_FLOAT_PRECISION SP_LOW_FLOAT_PRECISION

#define	SP_FFT_32BIT_PRECISION SP_32BIT_PRECISION

#define	SP_FFT_24BIT_PRECISION SP_24BIT_PRECISION

#define	SP_FFT_16BIT_PRECISION SP_16BIT_PRECISION

#define	SP_FFT_IGNORE_PRECISION SP_IGNORE_PRECISION

#define	SP_FFT_UNKNOWN_PRECISION SP_UNKNOWN_PRECISION

#define	SP_FFT_DEFAULT_PRECISION SP_FFT_FLOAT_PRECISION

#define	SP_FFT_SPEED_EXTREMELY_FAST SP_COMPUTE_SPEED_EXTREMELY_FAST

#define	SP_FFT_SPEED_VERY_FAST SP_COMPUTE_SPEED_VERY_FAST

#define	SP_FFT_SPEED_FASTER SP_COMPUTE_SPEED_FASTER

#define	SP_FFT_SPEED_FAST SP_COMPUTE_SPEED_FAST

#define	SP_FFT_SPEED_NORMAL SP_COMPUTE_SPEED_NORMAL

#define	SP_FFT_SPEED_SLOW SP_COMPUTE_SPEED_SLOW

#define	SP_FFT_SPEED_SLOWER SP_COMPUTE_SPEED_SLOWER

#define	SP_FFT_SPEED_VERY_SLOW SP_COMPUTE_SPEED_VERY_SLOW

#define	SP_FFT_SPEED_EXTREMELY_SLOW SP_COMPUTE_SPEED_EXTREMELY_SLOW

#define	SP_FFT_SPEED_UNKNOWN SP_COMPUTE_SPEED_UNKNOWN

Typedefs
typedef struct _spFFTRec *	spFFTRec

FFT Execution (<sp/fft.h>)
int	spfftf (float xRe, float xIm, long fftl, int inv)

int	spfft (double xRe, double xIm, long fftl, int inv)

int	sprfftf (float *data, long fftl, int inv)

int	sprfft (double *data, long fftl, int inv)

Data Shift for FFT (<sp/fft.h>)
void	datashifts (short *data, long length, long shift)

void	datashiftl (long *data, long length, long shift)

void	datashiftf (float *data, long length, long shift)

void	datashift (double *data, long length, long shift)

void	ridatashifts (short real, short imag, long length, long shift)

void	ridatashiftl (long real, long imag, long length, long shift)

void	ridatashiftf (float real, float imag, long length, long shift)

void	ridatashift (double real, double imag, long length, long shift)

void	circshifts (short *data, long length, long shift)

void	circshiftl (long *data, long length, long shift)

void	circshiftf (float *data, long length, long shift)

void	circshift (double *data, long length, long shift)

void	ricircshifts (short real, short imag, long length, long shift)

void	ricircshiftl (long real, long imag, long length, long shift)

void	ricircshiftf (float real, float imag, long length, long shift)

void	ricircshift (double real, double imag, long length, long shift)

void	fftturnf (float xRe, float xIm, long fftl)

void	fftturn (double xRe, double xIm, long fftl)

void	fftshiftf (float xRe, float xIm, long fftl)

void	fftshift (double xRe, double xIm, long fftl)

FFT Execution with FFT Plugin (<sp/fft.h>)
int	spGetNumFFTPlugin (void)

char *	xspSearchFFTPluginFile (int *index)

spBool	spSetDefaultFFTPlugin (const char *name)

spBool	spIsFFTPlugin (spPlugin *plugin)

spPlugin *	spLoadFFTPlugin (const char *name)

spBool	spFreeFFTPlugin (spPlugin *plugin)

spFFTSpeed	spGetFFTSpeed (spFFTPrecision precision)

spFFTRec	spInitBatchedFFTByPlugin (spPlugin *plugin, long order, long batch, spFFTPrecision precision)

spFFTRec	spInitBatchedFFT (long order, long batch, spFFTPrecision precision)

spFFTRec	spInitFFTByPlugin (spPlugin *plugin, long order, spFFTPrecision precision)

spFFTRec	spInitFFT (long order, spFFTPrecision precision)

spBool	spFreeFFT (spFFTRec fftrec)

spBool	spResetFFTOrder (spFFTRec fftrec, long order)

long	spGetFFTOrder (spFFTRec fftrec)

long	spGetFFTLength (spFFTRec fftrec)

long	spGetFFTBatch (spFFTRec fftrec)

spBool	spExecFFTF (spFFTRec fftrec, float real, float imag, int inv)

spBool	spExecFFT (spFFTRec fftrec, double real, double imag, int inv)

spBool	spExecRealFFTF (spFFTRec fftrec, float *data, int inv)

spBool	spExecRealFFT (spFFTRec fftrec, double *data, int inv)

spBool	spExecFFTPowerF (spFFTRec fftrec, float *data, float exponent)

spBool	spExecFFTPower (spFFTRec fftrec, double *data, double exponent)

Detailed Description

#include <sp/fft.h>

fft.h

Macro Definition Documentation

◆ spFFTSpeed

#define spFFTSpeed spComputeSpeed

Indicates speed of FFT computation.

◆ SP_FFT_HIGHEST_PRECISION

#define SP_FFT_HIGHEST_PRECISION SP_HIGHEST_PRECISION

Highest precision.

◆ SP_FFT_HIGH_DOUBLE_PRECISION

#define SP_FFT_HIGH_DOUBLE_PRECISION SP_HIGH_DOUBLE_PRECISION

Double type precision higher than normal double type.

◆ SP_FFT_DOUBLE_PRECISION

#define SP_FFT_DOUBLE_PRECISION SP_DOUBLE_PRECISION

double type precision.

Examples: lpctest.c.

◆ SP_FFT_LOW_DOUBLE_PRECISION

#define SP_FFT_LOW_DOUBLE_PRECISION SP_LOW_DOUBLE_PRECISION

double type precision lower than normal double type

◆ SP_FFT_HIGH_FLOAT_PRECISION

#define SP_FFT_HIGH_FLOAT_PRECISION SP_HIGH_FLOAT_PRECISION

float type precision higher than normal double type.

◆ SP_FFT_FLOAT_PRECISION

#define SP_FFT_FLOAT_PRECISION SP_FLOAT_PRECISION

float type precision.

◆ SP_FFT_LOW_FLOAT_PRECISION

#define SP_FFT_LOW_FLOAT_PRECISION SP_LOW_FLOAT_PRECISION

float type precision lower than normal float type

◆ SP_FFT_32BIT_PRECISION

#define SP_FFT_32BIT_PRECISION SP_32BIT_PRECISION

32-bit integer precision.

◆ SP_FFT_24BIT_PRECISION

#define SP_FFT_24BIT_PRECISION SP_24BIT_PRECISION

24-bit integer precision.

◆ SP_FFT_16BIT_PRECISION

#define SP_FFT_16BIT_PRECISION SP_16BIT_PRECISION

16-bit integer precision.

◆ SP_FFT_IGNORE_PRECISION

#define SP_FFT_IGNORE_PRECISION SP_IGNORE_PRECISION

Indicates that precision is ignored.

◆ SP_FFT_UNKNOWN_PRECISION

#define SP_FFT_UNKNOWN_PRECISION SP_UNKNOWN_PRECISION

Unknown precision.

◆ SP_FFT_DEFAULT_PRECISION

#define SP_FFT_DEFAULT_PRECISION SP_FFT_FLOAT_PRECISION

Default precision.

Examples: fftvec.c, simple_fft.c, and simple_rfft.c.

◆ SP_FFT_SPEED_EXTREMELY_FAST

#define SP_FFT_SPEED_EXTREMELY_FAST SP_COMPUTE_SPEED_EXTREMELY_FAST

Extremely fast speed.

◆ SP_FFT_SPEED_VERY_FAST

#define SP_FFT_SPEED_VERY_FAST SP_COMPUTE_SPEED_VERY_FAST

Very fast speed.

◆ SP_FFT_SPEED_FASTER

#define SP_FFT_SPEED_FASTER SP_COMPUTE_SPEED_FASTER

Faster speed.

◆ SP_FFT_SPEED_FAST

#define SP_FFT_SPEED_FAST SP_COMPUTE_SPEED_FAST

Fast speed.

◆ SP_FFT_SPEED_NORMAL

#define SP_FFT_SPEED_NORMAL SP_COMPUTE_SPEED_NORMAL

Normal speed.

◆ SP_FFT_SPEED_SLOW

#define SP_FFT_SPEED_SLOW SP_COMPUTE_SPEED_SLOW

Slow speed.

◆ SP_FFT_SPEED_SLOWER

#define SP_FFT_SPEED_SLOWER SP_COMPUTE_SPEED_SLOWER

Slower speed.

◆ SP_FFT_SPEED_VERY_SLOW

#define SP_FFT_SPEED_VERY_SLOW SP_COMPUTE_SPEED_VERY_SLOW

Very slow speed.

◆ SP_FFT_SPEED_EXTREMELY_SLOW

#define SP_FFT_SPEED_EXTREMELY_SLOW SP_COMPUTE_SPEED_EXTREMELY_SLOW

Extremely slow speed.

◆ SP_FFT_SPEED_UNKNOWN

#define SP_FFT_SPEED_UNKNOWN SP_COMPUTE_SPEED_UNKNOWN

Unknown speed.

Typedef Documentation

◆ spFFTRec

typedef struct _spFFTRec* spFFTRec

Definition of spFFTRec.

Function Documentation

◆ spfftf()

int spfftf	(	float *	xRe,
		float *	xIm,
		long	fftl,
		int	inv )

extern

Executes FFT of input data.

Parameters

[in]	xRe	The real part buffer of the data. The size of this buffer must be larger than `fftl` .
[in]	xIm	The imaginary part buffer of the data. The size of this buffer must be larger than `fftl` .
[in]	fftl	The number of FFT points.
[in]	inv	Nonzero value enables execution of the inverse FFT.

Return values

SP_SUCCESS	Success
SP_FAILURE	Failure

◆ spfft()

int spfft	(	double *	xRe,
		double *	xIm,
		long	fftl,
		int	inv )

extern

Executes FFT of input data.

Parameters

[in]	xRe	The real part buffer of the data. The size of this buffer must be larger than `fftl` .
[in]	xIm	The imaginary part buffer of the data. The size of this buffer must be larger than `fftl` .
[in]	fftl	The number of FFT points.
[in]	inv	Nonzero value enables execution of the inverse FFT.

Return values

SP_SUCCESS	Success
SP_FAILURE	Failure

Examples: simple_fft.c.

◆ sprfftf()

int sprfftf	(	float *	data,
		long	fftl,
		int	inv )

extern

Executes FFT of input real data.

Parameters

[in]	data	The buffer of the data. The size of this buffer must be larger than `fftl` . After FFT execution, `data` holds `data[0]=Re(X[0])`, `data[1]=Re(X[fftl/2])`, `data[2n]=Re(X[n])`, and `data[2n+1]=Im(X[n])` (n > 0, n < fftl/2), where `X[n]` is the complex spectrum. In other words, even elements except the index 0 and odd elements except the index 1 hold the real part and the imaginary part of the complex spectrum, respectively.
[in]	fftl	The number of FFT points.
[in]	inv	Nonzero value enables execution of the inverse FFT.

Return values

SP_SUCCESS	Success
SP_FAILURE	Failure

◆ sprfft()

int sprfft	(	double *	data,
		long	fftl,
		int	inv )

extern

Executes FFT of input real data.

Parameters

[in]	data	The buffer of the data. The size of this buffer must be larger than `fftl` . After FFT execution, `data` holds `data[0]=Re(X[0])`, `data[1]=Re(X[fftl/2])`, `data[2n]=Re(X[n])`, and `data[2n+1]=Im(X[n])` (n > 0, n < fftl/2), where `X[n]` is the complex spectrum. In other words, even elements except the index 0 and odd elements except the index 1 hold the real part and the imaginary part of the complex spectrum, respectively.
[in]	fftl	The number of FFT points.
[in]	inv	Nonzero value enables execution of the inverse FFT.

Return values

SP_SUCCESS	Success
SP_FAILURE	Failure

Examples: simple_rfft.c.

◆ datashifts()

void datashifts	(	short *	data,
		long	length,
		long	shift )

extern

Shifts input data. The pushed out data by shifting is discarded.

Parameters

[in]	data	The buffer containing input data. The input data is replaced with shifted data.
[in]	length	The size of `data` .
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ datashiftl()

void datashiftl	(	long *	data,
		long	length,
		long	shift )

extern

Shifts input data. The pushed out data by shifting is discarded.

Parameters

[in]	data	The buffer containing input data. The input data is replaced with shifted data.
[in]	length	The size of `data` .
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ datashiftf()

void datashiftf	(	float *	data,
		long	length,
		long	shift )

extern

Shifts input data. The pushed out data by shifting is discarded.

Parameters

[in]	data	The buffer containing input data. The input data is replaced with shifted data.
[in]	length	The size of `data` .
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ datashift()

void datashift	(	double *	data,
		long	length,
		long	shift )

extern

Shifts input data. The pushed out data by shifting is discarded.

Parameters

[in]	data	The buffer containing input data. The input data is replaced with shifted data.
[in]	length	The size of `data` .
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ ridatashifts()

void ridatashifts	(	short *	real,
		short *	imag,
		long	length,
		long	shift )

extern

Shifts input complex data. The pushed out data by shifting is discarded.

Parameters

[in]	real	The buffer containing input real data. The input data is replaced with shifted data.
[in]	imag	The buffer containing input imaginary data. The input data is replaced with shifted data.
[in]	length	The size of input data.
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ ridatashiftl()

void ridatashiftl	(	long *	real,
		long *	imag,
		long	length,
		long	shift )

extern

Shifts input complex data. The pushed out data by shifting is discarded.

Parameters

[in]	real	The buffer containing input real data. The input data is replaced with shifted data.
[in]	imag	The buffer containing input imaginary data. The input data is replaced with shifted data.
[in]	length	The size of input data.
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ ridatashiftf()

void ridatashiftf	(	float *	real,
		float *	imag,
		long	length,
		long	shift )

extern

Shifts input complex data. The pushed out data by shifting is discarded.

Parameters

[in]	real	The buffer containing input real data. The input data is replaced with shifted data.
[in]	imag	The buffer containing input imaginary data. The input data is replaced with shifted data.
[in]	length	The size of input data.
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ ridatashift()

void ridatashift	(	double *	real,
		double *	imag,
		long	length,
		long	shift )

extern

Shifts input complex data. The pushed out data by shifting is discarded.

Parameters

[in]	real	The buffer containing input real data. The input data is replaced with shifted data.
[in]	imag	The buffer containing input imaginary data. The input data is replaced with shifted data.
[in]	length	The size of input data.
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ circshifts()

void circshifts	(	short *	data,
		long	length,
		long	shift )

extern

Circular-shifts input data.

Parameters

[in]	data	The buffer containing input data. The input data is replaced with shifted data.
[in]	length	The size of input data.
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ circshiftl()

void circshiftl	(	long *	data,
		long	length,
		long	shift )

extern

Circular-shifts input data.

Parameters

[in]	data	The buffer containing input data. The input data is replaced with shifted data.
[in]	length	The size of input data.
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ circshiftf()

void circshiftf	(	float *	data,
		long	length,
		long	shift )

extern

Circular-shifts input data.

Parameters

[in]	data	The buffer containing input data. The input data is replaced with shifted data.
[in]	length	The size of input data.
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ circshift()

void circshift	(	double *	data,
		long	length,
		long	shift )

extern

Circular-shifts input data.

Parameters

[in]	data	The buffer containing input data. The input data is replaced with shifted data.
[in]	length	The size of input data.
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ ricircshifts()

void ricircshifts	(	short *	real,
		short *	imag,
		long	length,
		long	shift )

extern

Circular-shifts input complex data.

Parameters

[in]	real	The buffer containing input real data. The input data is replaced with shifted data.
[in]	imag	The buffer containing input imaginary data. The input data is replaced with shifted data.
[in]	length	The size of input data.
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ ricircshiftl()

void ricircshiftl	(	long *	real,
		long *	imag,
		long	length,
		long	shift )

extern

Circular-shifts input complex data.

Parameters

[in]	real	The buffer containing input real data. The input data is replaced with shifted data.
[in]	imag	The buffer containing input imaginary data. The input data is replaced with shifted data.
[in]	length	The size of input data.
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ ricircshiftf()

void ricircshiftf	(	float *	real,
		float *	imag,
		long	length,
		long	shift )

extern

Circular-shifts input complex data.

Parameters

[in]	real	The buffer containing input real data. The input data is replaced with shifted data.
[in]	imag	The buffer containing input imaginary data. The input data is replaced with shifted data.
[in]	length	The size of input data.
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ ricircshift()

void ricircshift	(	double *	real,
		double *	imag,
		long	length,
		long	shift )

extern

Circular-shifts input complex data.

Parameters

[in]	real	The buffer containing input real data. The input data is replaced with shifted data.
[in]	imag	The buffer containing input imaginary data. The input data is replaced with shifted data.
[in]	length	The size of input data.
[in]	shift	The shift length. Positive and negative values indicate shift to left and right respectively.

◆ fftturnf()

void fftturnf	(	float *	xRe,
		float *	xIm,
		long	fftl )

extern

Makes the real part of the spectrum reflection symmetric and the imaginary part rotational symmetric with respect to the index fftl/2. The right half data is not used for computation.

Parameters

[in]	xRe	The buffer of the real part of input data. The right half data is overwritten.
[in]	xIm	The buffer of the imaginary part of input data. The right half data is overwritten. If you don't use the immaginary part, NULL can be specified.
[in]	fftl	The number of FFT points. The buffer size must be larger than this value.

◆ fftturn()

void fftturn	(	double *	xRe,
		double *	xIm,
		long	fftl )

extern

Makes the real part of the spectrum reflection symmetric and the imaginary part rotational symmetric with respect to the index fftl/2. The right half data is not used for computation.

Parameters

[in]	xRe	The buffer of the real part of input data. The right half data is overwritten.
[in]	xIm	The buffer of the imaginary part of input data. The right half data is overwritten. If you don't use the immaginary part, NULL can be specified.
[in]	fftl	The number of FFT points. The buffer size must be larger than this value.

◆ fftshiftf()

void fftshiftf	(	float *	xRe,
		float *	xIm,
		long	fftl )

extern

Circular-shifts input data so that the index fftl/2 of the buffer moves to the index 0 .

Parameters

[in]	xRe	The buffer of the real part of input data. The input data is replaced with shifted data.
[in]	xIm	The buffer of the imaginary part of input data. The input data is replaced with shifted data.
[in]	fftl	The number of FFT points. The buffer size must be larger than this value.

◆ fftshift()

void fftshift	(	double *	xRe,
		double *	xIm,
		long	fftl )

extern

Circular-shifts input data so that the index fftl/2 of the buffer moves to the index 0 .

Parameters

[in]	xRe	The buffer of the real part of input data. The input data is replaced with shifted data.
[in]	xIm	The buffer of the imaginary part of input data. The input data is replaced with shifted data.
[in]	fftl	The number of FFT points. The buffer size must be larger than this value.

◆ spGetNumFFTPlugin()

int spGetNumFFTPlugin ( void )

extern

Gets the number of FFT plugins available.

Returns: The number of FFT plugins available.

◆ xspSearchFFTPluginFile()

char * xspSearchFFTPluginFile ( int * index )

extern

Finds the name of an FFT plugin registered.

Parameters

[in] index The address of a variable which holds the index to find. The index of the first call must be 0. After the function call, the value of the variable will be the index of the FFT plugin obtained.

Returns: A null-terminated string indicating the file name of the FFT plugin. You have to deallocate the memory by calling xspFree() . NULL will be returned if error occurs or no plugin is found anymore.

◆ spSetDefaultFFTPlugin()

spBool spSetDefaultFFTPlugin ( const char * name )

extern

Sets the specified FFT plugin default.

Parameters

[in] name A null-terminated string of the name of an FFT plugin.

Return values

SP_TRUE	Success
SP_FALSE	Failure

◆ spIsFFTPlugin()

spBool spIsFFTPlugin ( spPlugin * plugin )

extern

Checks if the plugin is an FFT plugin.

Parameters

[in] plugin spPlugin type pointer to check.

Return values

SP_TRUE	Success
SP_FALSE	Failure

◆ spLoadFFTPlugin()

spPlugin * spLoadFFTPlugin ( const char * name )

extern

Loads an FFT plugin.

Parameters

[in] name The name of the FFT plugin.

Returns: The loaded FFT plugin if successful or NULL if failure.

Examples: simple_fft.c, and simple_rfft.c.

◆ spFreeFFTPlugin()

spBool spFreeFFTPlugin ( spPlugin * plugin )

extern

Unloads the FFT plugin.

Parameters

[in] plugin The loaded FFT plugin obtained by spLoadFFTPlugin() .

Return values

SP_TRUE	Success
SP_FALSE	Failure

◆ spGetFFTSpeed()

spFFTSpeed spGetFFTSpeed ( spFFTPrecision precision )

extern

Gets speed of the default FFT engine. This function doesn't get speed of the plugin-based FFT engine if the plugin-based FFT is set to default.

Parameters

[in] precision The precision of the FFT engine to get speed in spFFTPrecision type.

Returns: The speed of the FFT engine in spFFTSpeed type.

◆ spInitBatchedFFTByPlugin()

spFFTRec spInitBatchedFFTByPlugin	(	spPlugin *	plugin,
		long	order,
		long	batch,
		spFFTPrecision	precision )

extern

Initializes resources for plugin-based FFT inside spFFTRec. The return value can be used for FFT-related functions such as spExecFFT() and spExecRealFFT() . The difference from spInitFFTByPlugin() is that a single FFT call executes multiple FFTs of the batch count in parallel. The buffer for spExecFFT() or spExecRealFFT() contains a series of vectors of the batch count.

Parameters

[in]	plugin	The FFT plugin used as FFT engine.
[in]	order	The order (the power of 2) of FFT points. For example, 8 for the FFT points of 256.
[in]	batch	The batch count.
[in]	precision	The precision of FFT engine such as SP_FFT_DEFAULT_PRECISION , SP_FFT_DOUBLE_PRECISION , SP_FFT_FLOAT_PRECISION and so on. Normally, SP_FFT_DEFAULT_PRECISION is recommended. Higher precision can make FFT execution slow on some environments.

Returns: The memory-allocated spFFTRec type variable including resources for FFT execution if successful or NULL if failure. You have to call spFreeFFT() to free the resources.

◆ spInitBatchedFFT()

spFFTRec spInitBatchedFFT	(	long	order,
		long	batch,
		spFFTPrecision	precision )

extern

Initializes resources for FFT inside spFFTRec. The return value can be used for FFT-related functions such as spExecFFT() and spExecRealFFT() . The difference from spInitFFT() is that a single FFT call executes multiple FFTs of the batch count in parallel. The buffer for spExecFFT() or spExecRealFFT() contains a series of vectors of the batch count.

Parameters

[in]	order	The order (the power of 2) of FFT points. For example, 8 for the FFT points of 256.
[in]	batch	The batch count.
[in]	precision	The precision of FFT engine such as SP_FFT_DEFAULT_PRECISION , SP_FFT_DOUBLE_PRECISION , SP_FFT_FLOAT_PRECISION and so on. Normally, SP_FFT_DEFAULT_PRECISION is recommended. Higher precision can make FFT execution slow on some environments.

Returns: The memory-allocated spFFTRec type variable including resources for FFT execution if successful or NULL if failure. You have to call spFreeFFT() to free the resources.

◆ spInitFFTByPlugin()

spFFTRec spInitFFTByPlugin	(	spPlugin *	plugin,
		long	order,
		spFFTPrecision	precision )

extern

Initializes resources for plugin-based FFT inside spFFTRec. The return value can be used for FFT-related functions such as spExecFFT() and spExecRealFFT() .

Parameters

[in]	plugin	The FFT plugin used as FFT engine.
[in]	order	The order (the power of 2) of FFT points. For example, 8 for the FFT points of 256.
[in]	precision	The precision of FFT engine such as SP_FFT_DEFAULT_PRECISION , SP_FFT_DOUBLE_PRECISION , SP_FFT_FLOAT_PRECISION and so on. Normally, SP_FFT_DEFAULT_PRECISION is recommended. Higher precision can make FFT execution slow on some environments.

Returns: The memory-allocated spFFTRec type variable including resources for FFT execution if successful or NULL if failure. You have to call spFreeFFT() to free the resources.

Examples: simple_fft.c, and simple_rfft.c.

◆ spInitFFT()

spFFTRec spInitFFT	(	long	order,
		spFFTPrecision	precision )

extern

Initializes resources for FFT inside spFFTRec. The return value can be used for FFT-related functions such as spExecFFT() and spExecRealFFT() .

Parameters

[in]	order	The order (the power of 2) of FFT points. For example, 8 for the FFT points of 256.
[in]	precision	The precision of FFT engine such as SP_FFT_DEFAULT_PRECISION , SP_FFT_DOUBLE_PRECISION , SP_FFT_FLOAT_PRECISION and so on. Normally, SP_FFT_DEFAULT_PRECISION is recommended. Higher precision can make FFT execution slow on some environments.

Returns: The memory-allocated spFFTRec type variable including resources for FFT execution if successful or NULL if failure. You have to call spFreeFFT() to free the resources.

Examples: fftvec.c, and lpctest.c.

◆ spFreeFFT()

spBool spFreeFFT ( spFFTRec fftrec )

extern

Frees the resources inside spFFTRec for FFT execution.

Parameters

[in] fftrec spFFTRec type variable obtained by spInitFFT() or similar functions.

Return values

SP_TRUE	Success
SP_FALSE	Failure

Examples: fftvec.c, lpctest.c, simple_fft.c, and simple_rfft.c.

◆ spResetFFTOrder()

spBool spResetFFTOrder	(	spFFTRec	fftrec,
		long	order )

extern

Resets the order of FFT. The buffer length must be larger than the length of 2 to the order-th power.

Parameters

[in]	fftrec	spFFTRec type variable obtained by spInitFFT() or similar functions.
[in]	order	The order (the power of 2) of FFT points. For example, 8 for the FFT points of 256.

Return values

SP_TRUE	Success
SP_FALSE	Failure

◆ spGetFFTOrder()

long spGetFFTOrder ( spFFTRec fftrec )

extern

Gets the order (the power of 2) of FFT points.

Parameters

[in] fftrec spFFTRec type variable obtained by spInitFFT() or similar functions.

Returns: The order of FFT points.

◆ spGetFFTLength()

long spGetFFTLength ( spFFTRec fftrec )

extern

Gets the number of FFT points.

Parameters

[in] fftrec spFFTRec type variable obtained by spInitFFT() or similar functions.

Returns: The number of FFT points.

Examples: fftvec.c, lpctest.c, simple_fft.c, and simple_rfft.c.

◆ spGetFFTBatch()

long spGetFFTBatch ( spFFTRec fftrec )

extern

Gets the batch size.

Parameters

[in] fftrec spFFTRec type variable obtained by spInitBatchedFFT() or spInitBatchedFFTByPlugin() .

Returns: The batch size.

◆ spExecFFTF()

spBool spExecFFTF	(	spFFTRec	fftrec,
		float *	real,
		float *	imag,
		int	inv )

extern

Executes FFT of input data with an FFT plugin.

Parameters

[in]	fftrec	spFFTRec type variable obtained by spInitFFT() or similar functions.
[in]	real	The real part buffer of the data. The size of this buffer must be larger than the number of FFT points.
[in]	imag	The imaginary part buffer of the data. The size of this buffer must be larger than the number of FFT points.
[in]	inv	Nonzero value enables execution of the inverse FFT.

Return values

SP_TRUE	Success
SP_FALSE	Failure

◆ spExecFFT()

spBool spExecFFT	(	spFFTRec	fftrec,
		double *	real,
		double *	imag,
		int	inv )

extern

Executes FFT of input data with an FFT plugin.

Parameters

[in]	fftrec	spFFTRec type variable obtained by spInitFFT() or similar functions.
[in]	real	The real part buffer of the data. The size of this buffer must be larger than the number of FFT points.
[in]	imag	The imaginary part buffer of the data. The size of this buffer must be larger than the number of FFT points.
[in]	inv	Nonzero value enables execution of the inverse FFT.

Return values

SP_TRUE	Success
SP_FALSE	Failure

Examples: simple_fft.c.

◆ spExecRealFFTF()

spBool spExecRealFFTF	(	spFFTRec	fftrec,
		float *	data,
		int	inv )

extern

Executes FFT of input real data with an FFT plugin.

Parameters

[in]	fftrec	spFFTRec type variable obtained by spInitFFT() or similar functions.
[in]	data	The buffer of the data. The size of this buffer must be larger than the number of FFT points. After FFT execution, `data` holds `data[0]=Re(X[0])`, `data[1]=Re(X[fftl/2])`, `data[2n]=Re(X[n])`, and `data[2n+1]=Im(X[n])` (n > 0, n < fftl/2), where `X[n]` is the complex spectrum. In other words, even elements except the index 0 and odd elements except the index 1 hold the real part and the imaginary part of the complex spectrum, respectively.
[in]	inv	Nonzero value enables execution of the inverse FFT.

Return values

SP_TRUE	Success
SP_FALSE	Failure

◆ spExecRealFFT()

spBool spExecRealFFT	(	spFFTRec	fftrec,
		double *	data,
		int	inv )

extern

Executes FFT of input real data with an FFT plugin.

Parameters

[in]	fftrec	spFFTRec type variable obtained by spInitFFT() or similar functions.
[in]	data	The buffer of the data. The size of this buffer must be larger than the number of FFT points. After FFT execution, `data` holds `data[0]=Re(X[0])`, `data[1]=Re(X[fftl/2])`, `data[2n]=Re(X[n])`, and `data[2n+1]=Im(X[n])` (n > 0, n < fftl/2), where `X[n]` is the complex spectrum. In other words, even elements except the index 0 and odd elements except the index 1 hold the real part and the imaginary part of the complex spectrum, respectively.
[in]	inv	Nonzero value enables execution of the inverse FFT.

Return values

SP_TRUE	Success
SP_FALSE	Failure

Examples: simple_rfft.c.

◆ spExecFFTPowerF()

spBool spExecFFTPowerF	(	spFFTRec	fftrec,
		float *	data,
		float	exponent )

extern

Calculates a power spectrum of input data with an FFT plugin.

Parameters

[in]	fftrec	spFFTRec type variable obtained by spInitFFT() or similar functions.
[in]	data	The buffer containing input data. The size of this buffer must be larger than the number of FFT points. After the function call, the buffer is replaced by the power spectrum calculated.
[in]	exponent	The exponent value to a power spectrum. For example, 1.0 and 0.5 correspond to the power spectrum and the amplitude spectrum, respectively.

Return values

SP_TRUE	Success
SP_FALSE	Failure

◆ spExecFFTPower()

spBool spExecFFTPower	(	spFFTRec	fftrec,
		double *	data,
		double	exponent )

extern

Calculates a power spectrum of input data with an FFT plugin.

Parameters

[in]	fftrec	spFFTRec type variable obtained by spInitFFT() or similar functions.
[in]	data	The buffer containing input data. The size of this buffer must be larger than the number of FFT points. After the function call, the buffer is replaced by the power spectrum calculated.
[in]	exponent	The exponent value to a power spectrum. For example, 1.0 and 0.5 correspond to the power spectrum and the amplitude spectrum, respectively.

Return values

SP_TRUE	Success
SP_FALSE	Failure

Data Structures

Macros

Typedefs

FFT Execution (<sp/fft.h>)

Data Shift for FFT (<sp/fft.h>)

FFT Execution with FFT Plugin (<sp/fft.h>)

Detailed Description

Macro Definition Documentation

◆ spFFTSpeed

◆ SP_FFT_HIGHEST_PRECISION

◆ SP_FFT_HIGH_DOUBLE_PRECISION

◆ SP_FFT_DOUBLE_PRECISION

◆ SP_FFT_LOW_DOUBLE_PRECISION

◆ SP_FFT_HIGH_FLOAT_PRECISION

◆ SP_FFT_FLOAT_PRECISION

◆ SP_FFT_LOW_FLOAT_PRECISION

◆ SP_FFT_32BIT_PRECISION

◆ SP_FFT_24BIT_PRECISION

◆ SP_FFT_16BIT_PRECISION

◆ SP_FFT_IGNORE_PRECISION

◆ SP_FFT_UNKNOWN_PRECISION

◆ SP_FFT_DEFAULT_PRECISION

◆ SP_FFT_SPEED_EXTREMELY_FAST

◆ SP_FFT_SPEED_VERY_FAST

◆ SP_FFT_SPEED_FASTER

◆ SP_FFT_SPEED_FAST

◆ SP_FFT_SPEED_NORMAL

◆ SP_FFT_SPEED_SLOW

◆ SP_FFT_SPEED_SLOWER

◆ SP_FFT_SPEED_VERY_SLOW

◆ SP_FFT_SPEED_EXTREMELY_SLOW

◆ SP_FFT_SPEED_UNKNOWN

Typedef Documentation

◆ spFFTRec

Function Documentation

◆ spfftf()

◆ spfft()

◆ sprfftf()

◆ sprfft()

◆ datashifts()

◆ datashiftl()

◆ datashiftf()

◆ datashift()

◆ ridatashifts()

◆ ridatashiftl()

◆ ridatashiftf()

◆ ridatashift()

◆ circshifts()

◆ circshiftl()

◆ circshiftf()

◆ circshift()

◆ ricircshifts()

◆ ricircshiftl()

◆ ricircshiftf()

◆ ricircshift()

◆ fftturnf()

◆ fftturn()

◆ fftshiftf()

◆ fftshift()

◆ spGetNumFFTPlugin()

◆ xspSearchFFTPluginFile()

◆ spSetDefaultFFTPlugin()

◆ spIsFFTPlugin()

◆ spLoadFFTPlugin()

◆ spFreeFFTPlugin()

◆ spGetFFTSpeed()

◆ spInitBatchedFFTByPlugin()

◆ spInitBatchedFFT()

◆ spInitFFTByPlugin()

◆ spInitFFT()

◆ spFreeFFT()

◆ spResetFFTOrder()

◆ spGetFFTOrder()

◆ spGetFFTLength()

◆ spGetFFTBatch()

◆ spExecFFTF()

◆ spExecFFT()

◆ spExecRealFFTF()

◆ spExecRealFFT()

◆ spExecFFTPowerF()