Developer Reference for Intel® Integrated Performance Primitives 2019
Computes the inverse discrete Fourier transform of a complex signal.
Case 1: Operation on real data type
IppStatus ippsDFTInv_CToC_32f(const Ipp32f* pSrcRe, const Ipp32f* pSrcIm, Ipp32f* pDstRe, Ipp32f* pDstIm, const IppsDFTSpec_C_32f* pDFTSpec, Ipp8u* pBuffer);
IppStatus ippsDFTInv_CToC_64f(const Ipp64f* pSrcRe, const Ipp64f* pSrcIm, Ipp64f* pDstRe, Ipp64f* pDstIm, const IppsDFTSpec_C_64f* pDFTSpec, Ipp8u* pBuffer);
Case 2: Operation on complex data type
IppStatus ippsDFTInv_CToC_32fc(const Ipp32fc* pSrc, Ipp32fc* pDst, const IppsDFTSpec_C_32fc* pDFTSpec, Ipp8u* pBuffer);
IppStatus ippsDFTInv_CToC_64fc(const Ipp64fc* pSrc, Ipp64fc* pDst, const IppsDFTSpec_C_64fc* pDFTSpec, Ipp8u* pBuffer);
ipps.h
Flavors declared in ipps.h:
Headers: ippcore.h, ippvm.h
Libraries: ippcore.lib, ippvm.lib
pDFTSpec |
Pointer to the DFT specification structure. |
pSrc |
Pointer to the input array containing complex values. |
pDst |
Pointer to the output array containing complex values. |
pSrcRe |
Pointer to the input array containing real parts of the signal. |
pSrcIm |
Pointer to the input array containing imaginary parts of the signal. |
pDstRe |
Pointer to the output array containing real parts of the signal. |
pDstIm |
Pointer to the output array containing imaginary parts of the signal. |
pBuffer |
Pointer to the work buffer. |
These functions compute the inverse DFT according to the pDFTSpec specification parameters: the transform len, the normalization flag, and the specific code hint.
The functions using the complex data type, for example with 32fc suffixes, process the input complex array pSrc and store the result in pDst.
The functions using the real data type and processing complex signals represented by separate real pSrcRe and imaginary pSrcIm parts, for example with 32f suffixes, store the result separately in pDstRe and pDstIm, respectively.
The function can be used with the external work buffer pBuffer to avoid memory allocation within the functions. Once the work buffer is allocated, it can be used for all following calls to the functions computing DFT. As internal allocation of memory is too expensive operation and depends on operating system and/or runtime libraries used - the use of an external buffer improves performance significantly, especially for the small size transforms.
Required buffer size must be computed by the corresponding function ippsDFTGet BufSize_C prior to using DFT computation functions.
If the external buffer is not specified (pBuffer is set to NULL), then the function itself allocates the memory needed for operation.
Optimization Notice |
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Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice. Notice revision #20110804 |
ippStsNoErr |
Indicates no error. |
ippStsNullPtrErr |
Indicates an error when one of the specified pointers with exception of pBuffer is NULL. |
ippStsContextMatchErr |
Indicates an error when the specification identifier pDFTSpec is incorrect. |
ippStsMemAllocErr |
Indicates an error when no memory is allocated. |
ippStsFftFlagErr |
Indicates an error when the flag value is incorrect. |