Visible to Intel only — GUID: GUID-2BFA533C-DCA2-4DF6-96CF-587E65FF18EF
Visible to Intel only — GUID: GUID-2BFA533C-DCA2-4DF6-96CF-587E65FF18EF
TopK
Returns maximum K values of an array.
Syntax
IppStatus ippsTopK_32f(const Ipp32f* pSrc, Ipp64s srcIndex, Ipp64s srcStride, Ipp64s srcLen, Ipp32f* pDstValue, Ipp64s* pDstIndex, Ipp64s dstLen, IppTopKMode hint, Ipp8u* pBuffer);
IppStatus ippsTopK_32s(const Ipp32s* pSrc, Ipp64s srcIndex, Ipp64s srcStride, Ipp64s srcLen, Ipp32s* pDstValue, Ipp64s* pDstIndex, Ipp64s dstLen, IppTopKMode hint, Ipp8u* pBuffer);
Include Files
ipps.h
Domain Dependencies
Headers: ippcore.h, ippvm.h
Libraries: ippcore.lib, ippvm.lib
Parameters
pSrc |
Pointer to the source vector. |
srcIndex |
Index of the pSrc[0] element, index of pSrc[n] is equal to srcIndex+n. |
srcStride |
The stride between elements in a source array. The unit of srcStride is Byte. |
srcLen |
Number of elements in the source vector. |
pDstValue |
Maximum values found by the function. |
dstIndex |
Indexes of maximum values. |
dstLen |
Number of K values to be returned, the function returns min(K, dstLen) elements. |
hint |
Parameter to choose the optimization that is most suitable for the srcLen+dstlen(K) combination, supported values: ippTopKAuto/ ippTopKDirect/ ippTopKRadix. |
pBuffer |
Pointer to the work buffer. |
Description
This function searches for dstLen maximum values and their indexes in an input vector. The function is designed to process large input vectors by small blocks, it takes into account results of previous blocks processing getting maximum values of pSrc and pDstValue and then combining the final results into pDstValue.
The srcIndex parameter stores the index of the first element pSrc[0] of each new block, thus supporting the continuous numbering of elements. Before calling the ippsTopK function, compute the required buffer size and initialize pDstValue and pDstIndex using the ippsTopKGetBufferSize and ippsTopKInit_32s functions, respectively.
Return Values
ippStsNoErr |
Indicates no error. |
ippStsNullPtrErr |
Indicates an error when at least one of the pointers is NULL. |
ippStsSizeErr |
Indicates an error when at least one of the srcLen or dstLen values is less than, or equal to zero. |
ippStsBadArgErr |
Indicates an error when the hint value is not supported. |
Example
/******************************************************************************* * Copyright (C) 2023 Intel Corporation. * * This software and the related documents are Intel copyrighted materials, and your use of them is governed by * the express license under which they were provided to you ('License'). Unless the License provides otherwise, * you may not use, modify, copy, publish, distribute, disclose or transmit this software or the related * documents without Intel's prior written permission. * This software and the related documents are provided as is, with no express or implied warranties, other than * those that are expressly stated in the License. * *******************************************************************************/ #include <stdio.h> #include "ipp.h" /* Next two defines are created to simplify code reading and understanding */ #define EXIT_MAIN exitLine: /* Label for Exit */ #define check_sts(st) if((st) != ippStsNoErr) goto exitLine; /* Go to Exit if Intel(R) Integrated Primitives (Intel(R) IPP) function returned status different from ippStsNoErr */ /* Results of ippMalloc() are not validated because Intel(R) IPP functions perform bad arguments check and will return an appropriate status */ int main() { Ipp32f src[10] = { 2.5, 1.0, 3.2, 4.7, 0.8, 5.6, 6.1, 3.9, 2.3, 4.0 }; Ipp32f dst[5]; Ipp64s idx[5]; IppStatus status; int i; printf("\nSource vector\n"); for (i = 0; i < 10; i++) printf("%f ", src[i]); Ipp64s buf_size; ippsTopKGetBufferSize(10, 5, ipp32f, ippTopKAuto, &buf_size); Ipp8u buf[buf_size]; ippsTopKInit_32f(dst, idx, 5); check_sts(status = ippsTopK_32f(src, 0, 4, 10, dst, idx, 5, ippTopKAuto, buf)); printf("\nTop k values:\n"); for (i = 0; i < 5; i++) printf("%f ", dst[i]); EXIT_MAIN printf("\nExit status %d (%s)\n", (int)status, ippGetStatusString(status)); return (int)status; }