UN PROGRAMME QUI UTILISE OPEN_MP POUR TROUVER DES NOMBRE PREMIER.

// OPEN_MP_01.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "windows.h"

#include "stdio.h"
#include "math.h"
#include "stdlib.h"
#include "omp.h"

int main(int argc, char *argv[])
{
	int i, j, limit;
	int start, end;          /* range of numbers to search */
	int number_of_primes=0;  /* number of primes found */
	int number_of_41primes=0;/* number of 4n+1 primes found */
	int number_of_43primes=0;/* number of 4n-1 primes found */
	int prime;               /* is the number prime? */
	int print_primes=0;      /* should each prime be printed? */
	DWORD dwStart, dwStop;
	float fElapsed;

	start = atoi(argv[1]);
	end = atoi(argv[2]);
	if (!(start % 2)) start++;

	if (argc == 4 && atoi(argv[3]) != 0) print_primes = 1;
	printf("Range to check for Primes: %d - %d\n\n",start, end);

	dwStart = GetTickCount();

#pragma omp parallel
	{
		int numPrimes=0;    /* local number of primes found */
		int num41Primes=0;  /* local number of 4n+1 primes found */
		int num43Primes=0;  /* local number of 4n-1 primes found */

#pragma omp for schedule(dynamic,1000)
		for(i = start; i <= end; i += 2) {
			int limit, j, prime;
			limit = (int) sqrt((float)i) + 1;
			prime = 1; /* assume number is prime */
			j = 3;
			while (prime && (j <= limit)) {
				if (i%j == 0) prime = 0;
				j += 2;
			}

			if (prime) {
				if (print_primes) printf("%5d is prime\n",i);
#pragma omp atomic
				number_of_primes++;

				if (i%4 == 1) {
#pragma omp atomic
					number_of_41primes++;
				}

				if (i%4 == 3) {
#pragma omp atomic
					number_of_43primes++;
				}

			}
		} // end for
	} // end parallel region

	dwStop = GetTickCount();
	fElapsed = (float) (((float)dwStop-(float)dwStart) / (float) 1000.0);
	printf("Total Elapsed time :%f Seconds\n",fElapsed);
	printf("\nProgram Done.\n %d primes found\n",number_of_primes);
	printf("\nNumber of 4n+1 primes found: %d\n",number_of_41primes);
	printf("\nNumber of 4n-1 primes found: %d\n",number_of_43primes);
}