FFTInit_R, FFTInit_C
FFTInit_R
, FFTInit_C
Initializes the FFT specification structure for real and complex signals.
Syntax
Case 1: Operation on real signal
IppStatus ippsFFTInit_R_32f(IppsFFTSpec_R_32f**
ppFFTSpec
, int
order
, int
flag
, IppHintAlgorithm
hint
, Ipp8u*
pSpec
, Ipp8u*
pSpecBuffer
);
IppStatus ippsFFTInit_R_64f(IppsFFTSpec_R_64f**
ppFFTSpec
, int
order
, int
flag
, IppHintAlgorithm
hint
, Ipp8u*
pSpec
, Ipp8u*
pSpecBuffer
);
Case 2: Operation on complex signal
IppStatus ippsFFTInit_C_32f(IppsFFTSpec_C_32f**
ppFFTSpec
, int
order
, int
flag
, IppHintAlgorithm
hint
, Ipp8u*
pSpec
, Ipp8u*
pSpecBuffer
);
IppStatus ippsFFTInit_C_64f(IppsFFTSpec_C_64f**
ppFFTSpec
, int
order
, int
flag
, IppHintAlgorithm
hint
, Ipp8u*
pSpec
, Ipp8u*
pSpecBuffer
);
IppStatus ippsFFTInit_C_32fc(IppsFFTSpec_C_32fc**
ppFFTSpec
, int
order
, int
flag
, IppHintAlgorithm
hint
, Ipp8u*
pSpec
, Ipp8u*
pSpecBuffer
);
IppStatus ippsFFTInit_C_64fc(IppsFFTSpec_C_64fc**
ppFFTSpec
, int
order
, int
flag
, IppHintAlgorithm
hint
, Ipp8u*
pSpec
, Ipp8u*
pSpecBuffer
);
Include Files
ipps.h
Domain Dependencies
Headers:
ippcore.h
,
ippvm.h
Libraries:
ippcore.lib
,
ippvm.lib
Parameters
- order
- FFT order. The input signal length isN= 2.order
- flag
- Specifies the result normalization method. The values for theflagargument are described in the section Flag and Hint Arguments.
- hint
- This parameter is deprecated. Set the value toippAlgHintNone.
- ppFFTSpec
- Double pointer to the FFT specification structure to be created.
- pSpec
- Pointer to the area for the FFT specification structure.
- pSpecBuffer
- Pointer to the work buffer.
Description
These functions initialize the FFT specification structure
ppFFTSpec
with the following parameters:- the transformorder. This parameter defines the transform length. Input and output signals are arrays of 2length.order
- the normalizationflag
- the specific codehint
Before calling these functions, you need to compute the size of the specification structure and the work buffer (if it is required) using the
ippsFFTGetSize_R
and ippsFFTGetSize_C
functions.If
pSpecBufferSize
returned by the ippsFFTGetSize
function is equal to zero, the parameter pSpecBuffer
can be NULL
. The suffix after the function name indicates the flavors of the FFT functions:
ippsFFTInit_C
is for complex flavors and ippsFFTInit_R
is for real flavors.Application Notes
The maximum values for signal length are:
Function Flavor | Max Length |
---|---|
C_32fc | 268435456 (2^28) |
C_64fc | 67108864 (2^27) |
Return Values
- ippStsNoErr
- Indicates no error.
- ippStsNullPtrErr
- Indicates an error when one of the specified pointers isNULL.
- ippStsFftOrderErr
- Indicates an error when theordervalue is incorrect.
- ippStsFftFlagErr
- Indicates an error when theflagvalue is incorrect.