Developer Reference

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

FFTInv_PackToR
,
FFTInv_PermToR
,
FFTInv_CCSToR

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

Syntax

Case 1: Not-in-place operation on input data in
Pack
format
IppStatus ippsFFTInv_PackToR_32f(const Ipp32f*
pSrc
, Ipp32f*
pDst
, const IppsFFTSpec_R_32f*
pFFTSpec
, Ipp8u*
pBuffer
);
IppStatus ippsFFTInv_PackToR_64f(const Ipp64f*
pSrc
, Ipp64f*
pDst
, const IppsFFTSpec_R_64f*
pFFTSpec
, Ipp8u*
pBuffer
);
Case 2: In-place operation on input data in
Pack
format
IppStatus ippsFFTInv_PackToR_32f_I(Ipp32f*
pSrcDst
, const IppsFFTSpec_R_32f*
pFFTSpec
, Ipp8u*
pBuffer
);
IppStatus ippsFFTInv_PackToR_64f_I(Ipp64f*
pSrcDst
, const IppsFFTSpec_R_64f*
pFFTSpec
, Ipp8u*
pBuffer
);
Case 3: Not-in-place operation on input data in
Perm
format
IppStatus ippsFFTInv_PermToR_32f(const Ipp32f*
pSrc
, Ipp32f*
pDst
, const IppsFFTSpec_R_32f*
pFFTSpec
, Ipp8u*
pBuffer
);
IppStatus ippsFFTInv_PermToR_64f(const Ipp64f*
pSrc
, Ipp64f*
pDst
, const IppsFFTSpec_R_64f*
pFFTSpec
, Ipp8u*
pBuffer
);
Case 4: In-place operation on input data in
Perm
format
IppStatus ippsFFTInv_PermToR_32f_I(Ipp32f*
pSrcDst
, const IppsFFTSpec_R_32f*
pFFTSpec
, Ipp8u*
pBuffer
);
IppStatus ippsFFTInv_PermToR_64f_I(Ipp64f*
pSrcDst
, const IppsFFTSpec_R_64f*
pFFTSpec
, Ipp8u*
pBuffer
);
Case 5 Not-in-place operation on input data in
CCS
format
IppStatus ippsFFTInv_CCSToR_32f(const Ipp32f*
pSrc
, Ipp32f*
pDst
, const IppsFFTSpec_R_32f*
pFFTSpec
, Ipp8u*
pBuffer
);
IppStatus ippsFFTInv_CCSToR_64f(const Ipp64f*
pSrc
, Ipp64f*
pDst
, const IppsFFTSpec_R_64f*
pFFTSpec
, Ipp8u*
pBuffer
);
Case 6: In-place operation on input data in
CCS
format
IppStatus ippsFFTInv_CCSToR_32f_I(Ipp32f*
pSrcDst
, const IppsFFTSpec_R_32f*
pFFTSpec
, Ipp8u*
pBuffer
);
IppStatus ippsFFTInv_CCSToR_64f_I(Ipp64f*
pSrcDst
, const IppsFFTSpec_R_64f*
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.
pDst
Pointer to the output array containing real values.
pSrcDst
Pointer to the input and output for the in-place operation.
pBuffer
Pointer to the external work buffer.
Description
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 function
ippsFFTGetSize_R
.
If the external buffer is not specified (
pBuffer
is set to
NULL
), then the function itself allocates the memory needed for operation.
ippsFFTInv_PackToR
. This function computes the inverse FFT of input data in
Pack
format.
ippsFFTInv_PermToR
. This function computes the inverse FFT of input data in
Perm
format.
ippsFFTInv_CCSToR
. This function computes the inverse FFT of input data in
CCS
format.
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

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