WHT

Performs Walsh-Hadamard transform of a real signal.

Syntax

IppStatus ippgWHT_32f(const Ipp32f* pSrc, Ipp32f* pDst, int order, int flag, Ipp8u* pBuffer);

IppStatus ippgWHT_64f(const Ipp64f* pSrc, Ipp64f* pDst, int order, int flag, Ipp8u* pBuffer);

IppStatus ippgWHT_<order>_32f(const Ipp32f* pSrc, Ipp32f* pDst, int flag, Ipp8u* pBuffer);

IppStatus ippgWHT_<order>_64f(const Ipp64f* pSrc, Ipp64f* pDst, int flag, Ipp8u* pBuffer);

supported value for <order>: integer in the range [1, 13].

Parameters

pSrc

Pointer to the input array.

pDst

Pointer to the output array.

flag

Specifies the result normalization method. The values for the flag argument are described in the section Flag and Hint Arguments.

order

Specifies the number of the samples 2order in the source signal [1, 13].

pBuffer

Pointer to the working buffer.

Description

The function ippgWHT is declared in the ippgen.h file.

The function computes the discrete Walsh-Hadamard transform (WHT) of a real signal for the fixed number of samples 2order. The number of samples can be specified by the parameter order, or by choosing the function flavor designed for the specific length of the signal and containing order in the function name, for example, the function flavor ippgWHT_11_32f performs the WHT of the 211 samples of the source signal. Intel IPP support WHT functions for fixed number of input samples corresponding to the values of order in the range [1, 13].

Caution iconCaution

Data vectors for these functions must be aligned to an appropriate number of bytes that is determined by the SIMD width that is supported by the customer's platform - use ippMalloc function for such alignment.

Optimization Notice

The Intel® Integrated Performance Primitives (Intel® IPP) library contains functions that are more highly optimized for Intel microprocessors than for other microprocessors. While the functions in the Intel® IPP library offer optimizations for both Intel and Intel-compatible microprocessors, depending on your code and other factors, you will likely get extra performance on Intel microprocessors.

While the paragraph above describes the basic optimization approach for the Intel® IPP library as a whole, the library may or may not be optimized to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include Intel® Streaming SIMD Extensions 2 (Intel® SSE2), Intel® Streaming SIMD Extensions 3 (Intel® SSE3), and Supplemental Streaming SIMD Extensions 3 (Intel® 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.

Intel recommends that you evaluate other library products to determine which best meets your requirements.

To avoid listing all the similar prototypes of function flavors of this type, only templates are given here. In the template the <order> modifier in a function name denotes a correspondent value of order.

The normalization method of the result is specified by the parameter flag.

This function requires the working buffer, its size must be computed with the function ippgWHTGetBufferSize beforehand.

The WHT is an involutary transform and the same function can be used both for forward and inverse transforms.

Return Values

ippStsNoErr

Indicates no error.

ippStsNullPtrErr

Indicates an error when one of the specified pointers is NULL.

ippStsFftFlagErr

Indicates an error when the flag value is incorrect.

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