Visible to Intel only — GUID: GUID-964F0942-5A2E-4132-A769-24BA9DBC6B8D
Visible to Intel only — GUID: GUID-964F0942-5A2E-4132-A769-24BA9DBC6B8D
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 is N= 2order. |
flag |
Specifies the result normalization method. The values for the flag argument are described in the section Flag and Hint Arguments. |
hint |
This parameter is deprecated. Set the value to ippAlgHintNone. |
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 transform order. This parameter defines the transform length. Input and output signals are arrays of 2 order length.
the normalization flag
the specific code hint
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 is NULL. |
ippStsFftOrderErr |
Indicates an error when the order value is incorrect. |
ippStsFftFlagErr |
Indicates an error when the flag value is incorrect. |