Intel® Integrated Performance Primitives Developer Reference

Developer Reference

  • 2021
  • 01/15/2021
  • Public Content
Contents

AutoCorrNorm

Calculates normal, biased, and unbiased auto-correlation of a vector.

Syntax

IppStatus ippsAutoCorrNorm_32f (const Ipp32f*
pSrc
, int
srcLen
, Ipp32f*
pDst
, int
dstLen
, IppEnum
algType
, Ipp8u*
pBuffer
);
IppStatus ippsAutoCorrNorm_64f (const Ipp64f*
pSrc
, int
srcLen
, Ipp64f*
pDst
, int
dstLen
, IppEnum
algType
, Ipp8u*
pBuffer
);
IppStatus ippsAutoCorrNorm_32fc (const Ipp32fc*
pSrc
, int
srcLen
, Ipp32fc*
pDst
, int
dstLen
, IppEnum
algType
, Ipp8u*
pBuffer
);
IppStatus ippsAutoCorrNorm_64fc (const Ipp64fc*
pSrc
, int
srcLen
, Ipp64fc*
pDst
, int
dstLen
, IppEnum
algType
, Ipp8u*
pBuffer
);
Include Files
ipps.h
Parameters
pSrc
Pointer to the source vector.
srcLen
Number of elements in the source vector.
pDst
Pointer to the destination vector. This vector stores the calculated auto-correlation of the source vector.
dstLen
Number of elements in the destination vector (length of auto-correlation).
algType
Bit-field mask for the algorithm type definition. Possible values are the results of composition of the
IppAlgType
 and
IppsNormOp
 values.
pBuffer
Pointer to the buffer for internal calculations.
Description
Before using these functions, you need to compute the size of the work buffer using the
ippsAutoCorrNormGetBufferSize
 function.
These functions calculate the normalized auto-correlation of the
pSrc
 vector of
srcLen
 length and store the results in the
pDst
 vector of
dstLen
 length. The result vector
pDst
 is calculated by the following equations:
where
The auto-correlation is computed for positive lags only. Auto-correlation for a negative lag is a complex conjugate of the auto-correlation for the equivalent positive lag.
Return Values
ippStsNoErr
Indicates no error.
ippStsNullPtrErr
Indicates an error when any of the specified pointers is
NULL
.
ippStsSizeErr
Indicates an error when
srcLen
 or
dstLen
 is less than, or equal to zero.
ippStsAlgTypeErr
Indicates an error when:
  • the result of the bitwise AND operation between the
    algType
     and
    ippAlgMask
     differs from the
    ippAlgAuto
    ,
    ippAlgDirect
    , or
    ippAlgFFT
     values;
  • the result of the bitwise AND operation between the
    algType
     and
    ippsNormMask
     differs from the
    ippsNormNone
    ,
    ippsNormA
    , or
    ippsNormB
     values.

Example

The code example below demonstrates how to use the
ippsAutoCorrNormGetBufferSize
 and
ippsAutoCorrNorm
 functions.
IppStatus AutoCorrNormExample (void) {
   IppStatus status;
   const int srcLen = 5, dstLen = 10;
   Ipp32f pSrc[srcLen] = {0.2f, 3.1f, 2.0f, 1.2f, -1.1f}, pDst[dstLen];
   IppEnum funCfg = (IppEnum)(ippAlgAuto|ippsNormB);
   int bufSize = 0;
   Ipp8u *pBuffer;

   status = ippsAutoCorrNormGetBufferSize(srcLen, dstLen, ipp32f, funCfg, &bufSize);

   if ( status != ippStsNoErr )
      return status;

   pBuffer = ippsMalloc_8u( bufSize );

   status = ippsAutoCorrNorm_32f(pSrc, srcLen, pDst, dstLen, funCfg, pBuffer);

   printf_32f("pDst", pDst, dstLen);

   ippsFree( pBuffer );
   return status;
}
The result is as follows:
pDst -> 3.3 2.0 0.6 -1.6 -0.2 0.0 0.0 0.0 0.0 0.0

Product and Performance Information

1

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