90 lines
2.2 KiB
C
90 lines
2.2 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <assert.h>
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#include <stdlib.h>
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#include <sys/time.h>
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#include "thread.h"
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/* Somme divide and conquer
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*
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* la durée doit être proportionnel à la valeur du résultat.
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* valgrind doit être content.
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* jusqu'à quelle valeur cela fonctionne-t-il ?
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*
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* support nécessaire:
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* - thread_create()
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* - thread_join() avec récupération de la valeur de retour
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* - retour sans thread_exit()
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*/
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struct dac_in_t {
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unsigned long* arr;
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int st;
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int end;
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};
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static void* s_dac_sum(void* _value)
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{
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thread_t th, th2;
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int err;
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void *res = NULL, *res2 = NULL;
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struct dac_in_t* in = (struct dac_in_t*) _value;
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/* on passe un peu la main aux autres pour eviter de faire uniquement la partie gauche de l'arbre */
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thread_yield();
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if (in->end <= in->st + 1)
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return (void*)in->arr[in->st];
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size_t mid = (in->end + in->st) / 2;
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struct dac_in_t in1 = {in->arr, in->st, mid};
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struct dac_in_t in2 = {in->arr, mid, in->end};
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err = thread_create(&th, s_dac_sum, (void*)&in1);
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assert(!err);
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err = thread_create(&th2, s_dac_sum, (void*)&in2);
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assert(!err);
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err = thread_join(th, &res);
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assert(!err);
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err = thread_join(th2, &res2);
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assert(!err);
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return (void*)((unsigned long) res + (unsigned long) res2);
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}
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int main(int argc, char *argv[])
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{
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unsigned long res;
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size_t n;
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struct timeval tv1, tv2;
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double s;
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if (argc < 2) {
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printf("argument manquant: entier n pour lequel dac_sum(n)\n");
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return EXIT_FAILURE;
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}
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n = atoi(argv[1]);
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unsigned long arr[n];
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for (size_t i = 0 ; i < n ; ++i)
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arr[i] = i + 1;
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struct dac_in_t in = { arr, .st=0, .end=n };
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gettimeofday(&tv1, NULL);
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res = (unsigned long)s_dac_sum((void *)&in);
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gettimeofday(&tv2, NULL);
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s = (tv2.tv_sec-tv1.tv_sec) + (tv2.tv_usec-tv1.tv_usec) * 1e-6;
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unsigned long expected = (n * (n + 1)) / 2;
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if (res != expected) {
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printf("dac(%lu) != %lu (FAILED)\n", res, expected);
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printf("GRAPH;%lu;%lu;%e;%s\n", n, res, s, "FAILED" );
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return EXIT_FAILURE;
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} else {
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printf("fibo(%lu) = %lu en %e s\n", n, res, s );
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printf("GRAPH;%lu;%lu;%e;%s\n", n, res, s, "SUCCESS" );
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return EXIT_SUCCESS;
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}
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}
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