Developer Reference

  • 2020
  • 07/15/2020
  • Public Content
Contents

DFTInv_CToC

Computes the inverse discrete Fourier transform of a complex signal.

Syntax

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
);
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 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.
Description
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
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.

Product and Performance Information

1

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