Intel® Integrated Performance Primitives Developer Reference

Developer Reference

  • 2021
  • 01/15/2021
  • Public Content
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
.
These functions 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.
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.

Product and Performance Information

1

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