Developer Reference

  • 2020
  • 10/21/2020
  • Public Content
Contents

FFTInv_CToC

Computes the inverse fast Fourier transform (FFT) of a complex signal.

Syntax

Case 1: Not-in-place operation on real data type
IppStatus ippsFFTInv_CToC_32f(const Ipp32f*
pSrcRe
, const Ipp32f*
pSrcIm
, Ipp32f*
pDstRe
, Ipp32f*
pDstIm
, const IppsFFTSpec_C_32f*
pFFTSpec
, Ipp8u*
pBuffer
);
IppStatus ippsFFTInv_CToC_64f(const Ipp64f*
pSrcRe
, const Ipp64f*
pSrcIm
, Ipp64f*
pDstRe
, Ipp64f*
pDstIm
, const IppsFFTSpec_C_64f*
pFFTSpec
, Ipp8u*
pBuffer
);
Case 2: Not-in-place operation on complex data type
IppStatus ippsFFTInv_CToC_32fc(const Ipp32fc*
pSrc
, Ipp32fc*
pDst
, const IppsFFTSpec_C_32fc*
pFFTSpec
, Ipp8u*
pBuffer
);
IppStatus ippsFFTInv_CToC_64fc(const Ipp64fc*
pSrc
, Ipp64fc*
pDst
, const IppsFFTSpec_C_64fc*
pFFTSpec
, Ipp8u*
pBuffer
);
Case 3: In-place operation on real data type
IppStatus ippsFFTInv_CToC_32f_I(Ipp32f*
pSrcDstRe
, Ipp32f*
pSrcDstIm
, const IppsFFTSpec_C_32f*
pFFTSpec
, Ipp8u*
pBuffer
);
IppStatus ippsFFTInv_CToC_64f_I(Ipp64f*
pSrcDstRe
, Ipp64f*
pSrcDstIm
, const IppsFFTSpec_C_64f*
pFFTSpec
, Ipp8u*
pBuffer
);
Case 4: In-place operation on complex data type
IppStatus ippsFFTInv_CToC_32fc_I(Ipp32fc*
pSrcDst
, const IppsFFTSpec_C_32fc*
pFFTSpec
, Ipp8u*
pBuffer
);
IppStatus ippsFFTInv_CToC_64fc_I(Ipp64fc*
pSrcDst
, const IppsFFTSpec_C_64fc*
pFFTSpec
, Ipp8u*
pBuffer
);
Include Files
ipps.h
Domain Dependencies
Headers:
ippcore.h
,
ippvm.h
Libraries:
ippcore.lib
,
ippvm.lib
Parameters
pFFTSpec
Pointer to the FFT 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.
pSrcDst
Pointer to the input and output array containing complex values (for the in-place operation).
pSrcDstRe
Pointer to the input and output array containing real parts of the signal(for the in-place operation).
pSrcDstIm
Pointer to the input and output array containing imaginary parts of the signal(for the in-place operation).
pBuffer
Pointer to the external work buffer.
Description
This function computes the inverse FFT of a complex signal according to the
pFFTSpec
specification parameters: the transform
order
, the normalization
flag
, and the specific code
hint
. The FFT specification structure must be initialized by the
ippsFFTInit_C
function beforehand.
The function flavors using the complex data type, for example with the
32fc
suffixes, process the input complex array
pSrc
and store the result in
pDst
. Their in-place flavors use the complex array
pSrcDst
.
The function flavors using the real data type and processing complex signals represented by separate real
pSrcRe
and imaginary
pSrcIm
parts, for example with the
32f
suffixes, store the result separately in
pDstRe
and
pDstIm
, respectively. Their in-place flavors uses separate real and imaginary arrays
pSrcDstRe
and
pSrcDstIm
, respectively.
The function may 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 FFT. 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.
The size of the external buffer must be previously computed by the
ippsFFTGetSize_C
function.
If the external buffer is not specified (
pBuffer
is set to
NULL
), then the function itself allocates the memory needed for operation.
The length of the FFT must be a power of 2.
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
pFFTSpec
is incorrect.
ippStsMemAllocErr
Indicates an error when no memory is allocated.

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