Notes

#!/bin/bash

echo "Secuencial"
export OMP_NUM_THREADS=1
gcc -o secuencial wallis_par.c -fopenmp
for i in `seq 1 30`
do
./secuencial
done
echo
echo "Paralelo 2 threads"
export OMP_NUM_THREADS=2
gcc -o paralelo2 wallis_par.c -fopenmp
for i in `seq 1 30`
do
./paralelo2
done
echo

echo "Paralelo 4 threads"
export OMP_NUM_THREADS=4
gcc -o paralelo4 wallis_par.c -fopenmp
for i in `seq 1 30`
do
./paralelo4
done
echo

echo "Paralelo 8 threads"
export OMP_NUM_THREADS=8
gcc -o paralelo8 wallis_par.c -fopenmp
for i in `seq 1 30`
do
./paralelo8
done
echo

echo "Paralelo 12 threads"
export OMP_NUM_THREADS=12
gcc -o paralelo12 wallis_par.c -fopenmp
for i in `seq 1 30`
do
./paralelo12
done
echo

echo "Paralelo 16 threads"
export OMP_NUM_THREADS=16
gcc -o paralelo16 wallis_par.c -fopenmp
for i in `seq 1 30`
do
./paralelo16
done
echo




//---------------------------------
#include <sys/time.h>
#include <stdio.h>
#include <omp.h>

#define N 1000000

double tiempos(struct timeval , struct timeval );

int main(){
double pi = 4; //Primera aproximación al valor de pi según la formula de Wallis
int k = 1;
struct timeval t_start, t_end;

gettimeofday(&t_start , NULL ); //Obtener tiempo inicial

omp_set_num_threads(16);
printf("%dn", omp_get_num_threads());

#pragma omp parallel for schedule(static, N/omp_get_num_threads()) //Paralelizar la ejecucion del lazo que calcula el valor de pi
for(k = 1; k < N; k++){
pi = pi*(1.0 - (1.0 / ((2.0 * k + 1.0) * (2.0 * k + 1.0))));
//printf("k:%d - pi:%f n", k, pi);
}

gettimeofday(&t_end , NULL ); //Obtener tiempo final

printf("%fn", tiempos(t_start, t_end));
//printf("%f n", pi);
return 0;
}

//Formula para cálculo de la diferencia de tiempo
double tiempos(struct timeval inicio, struct timeval fin){
double mil_time, sec_time , usec_time;
sec_time = fin.tv_sec - inicio.tv_sec;
usec_time = fin.tv_usec - inicio.tv_usec;
mil_time = ((1000*sec_time)+(usec_time/1000.0)) + 0.5;
return mil_time/1000.0;
}