vectorsum_parallel.c

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include <pthread.h>
#include <sys/types.h>
#include <unistd.h>

#define MAX 10000

#define NTHREADS 10

struct infojob {
	int ini;	/* posición inicial */
	int fin;	/* posición final */
	int res;	/* resultado parcial */
};

int globalvector[MAX];
struct infojob jobs_info[NTHREADS];
pthread_mutex_t mutex;

void* sum(void* pointer) {
  struct infojob* job = (struct infojob*)pointer;
	int i;
  for (i = job->ini; i <= job->fin; ++i) {
    pthread_mutex_lock(&mutex);
    job->res += globalvector[i];
    pthread_mutex_unlock(&mutex);
  }
  pthread_exit(0);
}

int main()
{
  int i;
  int suma = 0;
  char buf[100];
  pthread_mutex_init(&mutex, NULL);

	/* init global vector */
  for (i=0; i< MAX; i++) {
	  globalvector[i] = i;
  }

  pthread_t thr[NTHREADS];
  for (i=0; i<NTHREADS; ++i) {
		jobs_info[i].ini = (MAX/NTHREADS)*i;
		jobs_info[i].fin = (MAX/NTHREADS)*(i+1)-1;
		jobs_info[i].res = 0;
    pthread_create(&thr[i], NULL, &sum, &jobs_info[i]);
  }

  for (i=0; i<NTHREADS; i++) {
		pthread_join(thr[i], NULL);
		suma += jobs_info[i].res;
  }	

  sprintf (buf, "El resultado de la suma es %d\n", suma);
  write (1, buf, strlen(buf));
  return 0;
}