Intel® Integrated Performance Primitives Developer Guide and Reference

ID 790148
Date 11/07/2023
Public

A newer version of this document is available. Customers should click here to go to the newest version.

Document Table of Contents

DFTFwd_RToPack, DFTFwd_RToPerm, DFTFwd_RToCCS

Computes the forward discrete Fourier transform of a real signal.

Syntax

Case 1: Result in Pack format

IppStatus ippsDFTFwd_RToPack_32f(const Ipp32f* pSrc, Ipp32f* pDst, const IppsDFTSpec_R_32f* pDFTSpec, Ipp8u* pBuffer);

IppStatus ippsDFTFwd_RToPack_64f(const Ipp64f* pSrc, Ipp64f* pDst, const IppsDFTSpec_R_64f* pDFTSpec, Ipp8u* pBuffer);

supported value for <len>: integer in the range [2, 64].

Case 2: Result in Perm format

IppStatus ippsDFTFwd_RToPerm_32f(const Ipp32f* pSrc, Ipp32f* pDst, const IppsDFTSpec_R_32f* pDFTSpec, Ipp8u* pBuffer);

IppStatus ippsDFTFwd_RToPerm_64f(const Ipp64f* pSrc, Ipp64f* pDst, const IppsDFTSpec_R_64f* pDFTSpec, Ipp8u* pBuffer);

Case 3: Result in CCS format

IppStatus ippsDFTFwd_RToCCS_32f(const Ipp32f* pSrc, Ipp32f* pDst, const IppsDFTSpec_R_32f* pDFTSpec, Ipp8u* pBuffer);

IppStatus ippsDFTFwd_RToCCS_64f(const Ipp64f* pSrc, Ipp64f* pDst, const IppsDFTSpec_R_64f* pDFTSpec, Ipp8u* pBuffer);

Include Files

ipps.h

Domain Dependencies

Flavors declared in ipps.h:

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 real values .

pDst

Pointer to the output array containing packed complex values.

pBuffer

Pointer to the work buffer.

Description

These functions compute the forward DFT of a real signal. The result of the forward transform (that is in the frequency-domain) of real signals is represented in several possible packed formats: Pack, Perm, or CCS. The data can be packed due to the symmetry property of the DFT transform of a real signal. Tables show how the output results are arranged in the packed formats.

These functions compute the forward DFT according to the pDFTSpec specification parameters: the transform len, the normalization flag, and the specific code hint.

Use these functions with the external work buffer pBuffer. Once the work buffer is allocated, it can be used for all following calls to the functions computing DFT. The use of an external buffer improves performance significantly, especially for the small size transforms.

ippsDFTFwd_RToPack. These functions compute the forward DFT and stores the result in Pack format.

ippsDFTFwd_RToPerm. These functions compute the forward DFT and stores the result in Perm format.

ippsDFTFwd_RToCCS. These functions compute the forward DFT and stores the result in CCS format.

Product and Performance Information

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.

Notice revision #20201201

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.