Developer Reference for Intel® Integrated Performance Primitives 2018

DFTInv_PackToR, DFTInv_PermToR, DFTInv_CCSToR

Computes the inverse discrete Fourier transform of a real signal.

Syntax

Case 1: Input data in Pack format

IppStatus ippsDFTInv_PackToR_32f(const Ipp32f* pSrc, Ipp32f* pDst, const IppsDFTSpec_R_32f* pDFTSpec, Ipp8u* pBuffer);

IppStatus ippsDFTInv_PackToR_64f(const Ipp64f* pSrc, Ipp64f* pDst, const IppsDFTSpec_R_64f* pDFTSpec, Ipp8u* pBuffer);

Case 2: Input data in Perm format

IppStatus ippsDFTInv_PermToR_32f(const Ipp32f* pSrc, Ipp32f* pDst, const IppsDFTSpec_R_32f* pDFTSpec, Ipp8u* pBuffer);

IppStatus ippsDFTInv_PermToR_64f(const Ipp64f* pSrc, Ipp64f* pDst, const IppsDFTSpec_R_64f* pDFTSpec, Ipp8u* pBuffer);

Case 3: Input data in CCS format

IppStatus ippsDFTInv_CCSToR_32f(const Ipp32f* pSrc, Ipp32f* pDst, const IppsDFTSpec_R_32f* pDFTSpec, Ipp8u* pBuffer);

IppStatus ippsDFTInv_CCSToR_64f(const Ipp64f* pSrc, Ipp64f* pDst, const IppsDFTSpec_R_64f* pDFTSpec, Ipp8u* pBuffer);

Include Files

16s_Sfs flavors: ipps.h

Domain Dependencies

16s_Sfs:

Headers: ippcore.h, ippvm.h

Libraries: ippcore.lib, ippvm.lib

Parameters

pDFTSpec

Pointer to the DFT specification structure.

pSrc

Pointer to the input array containing packed complex values.

pDst

Pointer to the output array containing real values.

pBuffer

Pointer to the work buffer.

Description

These functions compute the inverse DFT of a real signal. The input data (that is in the frequency-domain) are represented in several possible packed formats: Pack, Perm, or CCS. Tables show how the input data can be represented in the packed formats.

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.

If the external buffer is not specified (pBuffer is set to NULL), then the function itself allocates the memory needed for operation.

ippsDFTInv_PackToR. This function computes the inverse DFT for input data in Pack format.

ippsDFTInv_PermToR. This function computes the inverse DFT for input data in Perm format.

ippsDFTInv_CCSToR. This function computes the inverse DFT for input data in CCS format.

Optimization Notice

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

Return Values

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.