/*------------------------------------------------------------------*/
int main(int argc, char* argv[]) {
FILE* digraph_file;
tour_t tour;
double start, finish;
if (argc != 2) Usage(argv[0]);
digraph_file = fopen(argv[1], "r");
if (digraph_file == NULL) {
fprintf(stderr, "Can't open %s\n", argv[1]);
Usage(argv[0]);
}
Read_digraph(digraph_file);
fclose(digraph_file);
# ifdef DEBUG
Print_digraph();
# endif
avail = Init_stack();
best_tour = Alloc_tour();
Init_tour(best_tour, INFINITY);
# ifdef DEBUG
Print_tour(best_tour, "Best tour");
printf("City count = %d\n", City_count(best_tour));
printf("Cost = %d\n\n", Tour_cost(best_tour));
# endif
tour = Alloc_tour();
Init_tour(tour, 0);
# ifdef DEBUG
Print_tour(tour, "Starting tour");
printf("City count = %d\n", City_count(tour));
printf("Cost = %d\n\n", Tour_cost(tour));
# endif
GET_TIME(start);
Iterative_dfs(tour);
GET_TIME(finish);
Free_tour(tour);
Print_tour(best_tour, "Best tour");
printf("Cost = %d\n", best_tour->cost);
printf("Elapsed time = %e seconds\n", finish-start);
free(best_tour->cities);
free(best_tour);
Free_avail();
free(digraph);
return 0;
} /* main */
/*------------------------------------------------------------------
* Function: Iterative_dfs
* Purpose: Use a stack variable to implement an iterative version
* of depth-first search
* In arg:
* tour: partial tour of cities visited so far (just city 0)
* Globals in:
* n: total number of cities in the problem
* Notes:
* 1 The input tour is modified during execution of search,
* but returned to its original state before returning.
* 2. The Update_best_tour function will modify the global var
* best_tour
*/
void Iterative_dfs(tour_t tour) {
city_t nbr;
my_stack_t stack;
tour_t curr_tour;
stack = Init_stack();
Push(stack, tour);
while (!Empty(stack)) {
curr_tour = Pop(stack);
# ifdef DEBUG
printf("Popped tour = %p and %p\n", curr_tour, curr_tour->cities);
Print_tour(curr_tour, "Popped");
printf("\n");
# endif
if (City_count(curr_tour) == n) {
if (Best_tour(curr_tour))
Update_best_tour(curr_tour);
} else {
for (nbr = n-1; nbr >= 1; nbr--)
if (Feasible(curr_tour, nbr)) {
Add_city(curr_tour, nbr);
Push(stack, curr_tour);
Remove_last_city(curr_tour);
}
}
Free_tour(curr_tour);
}
Free_stack(stack);
} /* Iterative_dfs */
/*------------------------------------------------------------------
* Function: Push_avail
* Purpose: Store a tour in the available list
* In arg: tour
* In/out Global:
*/
void Push_avail(tour_t tour) {
if (avail->list_sz == n*n) {
fprintf(stderr, "Available stack overflow!\n");
free(tour->cities);
free(tour);
} else {
# ifdef DEBUG
printf("In Push_avail, loc = %d, pushing %p and %p\n",
avail->list_sz, tour, tour->cities);
Print_tour(tour, "About to be pushed onto avail");
printf("\n");
# endif
avail->list[avail->list_sz] = tour;
(avail->list_sz)++;
}
} /* Push_avail */
/*------------------------------------------------------------------*/
int main(int argc, char* argv[]) {
FILE* mat_file;
long thread;
pthread_t* thread_handles;
thread_count = strtol(argv[1], NULL, 10);
mat_file = fopen(argv[2], "r");
if (mat_file == NULL) {
fprintf(stderr, "Can't open %s\n", argv[2]);
Usage(argv[0]);
}
Read_mat(mat_file);
fclose(mat_file);
Initialize_tour(&best_tour);
best_tour.cost = INFINITY;
thread_handles = malloc(thread_count*sizeof(pthread_t));
for(thread = 0; thread < thread_count; thread++){
pthread_create(&thread_handles[thread], NULL, Search, (void*) thread);
}
for(thread = 0; thread < thread_count; thread++){
pthread_join(thread_handles[thread], NULL);
}
Print_tour(&best_tour, "Best tour");
printf("Cost = %d\n", best_tour.cost);
pthread_mutex_unlock(&mutex);
free(best_tour.cities);
free(mat);
free(thread_handles);
return 0;
} /* main */
