WCudaMSE/Student_OMP/src/cpp/core/omp/02_pi/06_pi_for_atomic.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 isPiOMPforAtomic_Ok(int n);
  20
  21 /*--------------------------------------*\
  22  |*             Private                 *|
  23  \*-------------------------------------*/
  24
  25 static double piOMPforAtomic(int n);
  26
  27 /*----------------------------------------------------------------------*\
  28  |*                     Implementation                                  *|
  29  \*---------------------------------------------------------------------*/
  30
  31 /*--------------------------------------*\
  32  |*             Public                  *|
  33  \*-------------------------------------*/
  34
  35 bool isPiOMPforAtomic_Ok(int n)
  36     {
  37     return isAlgoPI_OK(piOMPforAtomic, n, "Pi OMP for atomic");
  38     }
  39
  40 /*--------------------------------------*\
  41  |*             Private                 *|
  42  \*-------------------------------------*/
  43
  44 /**
  45  * synchronisation couteuse!
  46  */
  47 double piOMPforAtomic(int n)
  48     {
  49     double sum = 0;
  50     double xi;
  51     const double DX = 1.0/(double)n;
  52
  53     #pragma omp parralel for private(xi)
  54         for (int i = 0; i < n; i++)
  55             {
  56             xi = i*DX;
  57             #pragma omp atomic
  58                 sum += fpi(xi); // Uniquement l'operateur += est atomi, 'fpi' est exécuté en parralèle.
  59             }
  60
  61     return sum * DX;
  62     }
  63
  64 /*----------------------------------------------------------------------*\
  65  |*                     End                                             *|
  66  \*---------------------------------------------------------------------*/
  67