WCudaMSE/Student_OMP/src/cpp/core/omp/02_pi/08_pi_for_reduction.cpp

   1 #include <omp.h>
   2 #include "00_pi_tools.h"
   3 #include "OmpTools.h"
   4
   5 /*----------------------------------------------------------------------*\
   6  |*                     Declaration                                     *|
   7  \*---------------------------------------------------------------------*/
   8
   9 /*--------------------------------------*\
  10  |*             Imported                *|
  11  \*-------------------------------------*/
  12
  13
  14
  15 /*--------------------------------------*\
  16  |*             Public                  *|
  17  \*-------------------------------------*/
  18
  19 bool isPiOMPforReduction_Ok(int n);
  20
  21 /*--------------------------------------*\
  22  |*             Private                 *|
  23  \*-------------------------------------*/
  24
  25 static double piOMPforReduction(int n);
  26
  27 /*----------------------------------------------------------------------*\
  28  |*                     Implementation                                  *|
  29  \*---------------------------------------------------------------------*/
  30
  31 /*--------------------------------------*\
  32  |*             Public                  *|
  33  \*-------------------------------------*/
  34
  35 bool isPiOMPforReduction_Ok(int n)
  36     {
  37     return isAlgoPI_OK(piOMPforReduction, n, "Pi OMP for reduction-integrer");
  38     }
  39
  40 /*--------------------------------------*\
  41  |*             Private                 *|
  42  \*-------------------------------------*/
  43
  44 /**
  45  * pattern omp usefull : idem desyncronisation-promotionTab ,mais avec syntaxe plus courte!
  46  * Si on enleve le pragma, le code est le meme que le sequentiel!
  47  */
  48 double piOMPforReduction(int n)
  49     {
  50     double sum = 0;
  51     double xi;
  52     const double DX = 1.0/(double)n;
  53
  54 #pragma omp parallel for private(xi) reduction(+:sum)
  55     for (int i = 0; i < n; i++)
  56         {
  57         xi = i*DX;
  58         sum += fpi(xi);
  59         }
  60
  61     return sum * DX;
  62     }
  63
  64
  65
  66
  67 /*----------------------------------------------------------------------*\
  68  |*                     End                                             *|
  69  \*---------------------------------------------------------------------*/
  70