/* nag_omp_set_max_active_levels (x06ajc) Example Program.
*
* Copyright 2024 Numerical Algorithms Group.
*
* Mark 30.1, 2024.
*/
#include <stdio.h>
#include <nag.h>
int main(void)
{
/* Scalars */
Integer inner_num, inner_threads, max_active_levels, outer_threads, total,
total_2, total_3, exit_status = 0;
/* Nag Types */
NagError fail;
INIT_FAIL(fail);
/* Initialise totals */
total = 0;
total_2 = 0;
total_3 = 0;
/* Set number of threads for inner and outer parallel regions */
inner_threads = 7;
outer_threads = 3;
nag_omp_set_num_threads(outer_threads, &fail);
/* Testing implementation default behaviour */
printf("nag_omp_set_max_active_levels (x06ajc) Example Program Results\n");
#ifdef _OPENMP
#pragma omp parallel shared (inner_threads,total,inner_num,fail), default (none)
#endif
{
#ifdef _OPENMP
#pragma omp master
#endif
{
printf("Implementation max active levels default: %11" NAG_IFMT "\n",
nag_omp_get_max_active_levels());
printf(" No. threads in 1st parallel region: %13" NAG_IFMT "\n",
nag_omp_get_num_threads());
}
#ifdef _OPENMP
#pragma omp barrier
#endif
nag_omp_set_num_threads(inner_threads, &fail);
#ifdef _OPENMP
#pragma omp parallel shared (total,inner_num), default (none)
#endif
{
/* Get max number of threads inside second active parallel region */
inner_num = nag_omp_get_num_threads();
#ifdef _OPENMP
#pragma omp atomic
#endif
total++;
}
#ifdef _OPENMP
#pragma omp master
#endif
{
printf(" No. threads in 2nd parallel region: %13" NAG_IFMT "\n",
inner_num);
}
}
printf(" Total threads: %34" NAG_IFMT "\n\n\n",total);
/* Set max active parallel regions */
max_active_levels = 2;
nag_omp_set_max_active_levels(max_active_levels, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_omp_set_max_active_levels (x06ajc).\n%s\n",
fail.message);
fflush(stdout);
exit_status = 1;
goto END;
}
/* Set number of threads for inner and outer parallel regions */
inner_threads = 7;
outer_threads = 3;
nag_omp_set_num_threads(outer_threads, &fail);
/* Testing with max active levels set to 2 */
#ifdef _OPENMP
#pragma omp parallel \
shared (inner_threads,total_2,inner_num,fail,max_active_levels),\
default (none)
#endif
{
#ifdef _OPENMP
#pragma omp master
#endif
{
printf(" Max active levels set to: %23" NAG_IFMT "\n",
max_active_levels);
printf(" x06ak return value: %29" NAG_IFMT "\n",
nag_omp_get_max_active_levels());
printf(" No. threads in 1st parallel region: %13" NAG_IFMT "\n",
nag_omp_get_num_threads());
}
#ifdef _OPENMP
#pragma omp barrier
#endif
nag_omp_set_num_threads(inner_threads, &fail);
#ifdef _OPENMP
#pragma omp parallel shared (total_2,inner_num), default (none)
#endif
{
/* Get max number of threads inside second active parallel region */
inner_num = nag_omp_get_num_threads();
#ifdef _OPENMP
#pragma omp atomic
#endif
total_2++;
}
#ifdef _OPENMP
#pragma omp master
#endif
{
printf(" No. threads in 2nd parallel region: %13" NAG_IFMT "\n",
inner_num);
}
}
printf(" Total threads: %34" NAG_IFMT "\n\n\n",total_2);
/* Set max active parallel regions */
max_active_levels = 1;
nag_omp_set_max_active_levels(max_active_levels, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_omp_set_max_active_levels (x06ajc).\n%s\n",
fail.message);
fflush(stdout);
exit_status = 1;
goto END;
}
/* Testing with max active levels set to 1 */
#ifdef _OPENMP
#pragma omp parallel \
shared (inner_threads,total_3,inner_num,fail,max_active_levels), \
default (none)
#endif
{
#ifdef _OPENMP
#pragma omp master
#endif
{
printf(" Max active levels set to: %23" NAG_IFMT "\n",
max_active_levels);
printf(" x06ak return value: %29" NAG_IFMT "\n",
nag_omp_get_max_active_levels());
printf(" No. threads in 1st parallel region: %13" NAG_IFMT "\n",
nag_omp_get_num_threads());
}
#ifdef _OPENMP
#pragma omp barrier
#endif
nag_omp_set_num_threads(inner_threads, &fail);
#ifdef _OPENMP
#pragma omp parallel shared (total_3,inner_num), default (none)
#endif
{
/* Get max number of threads inside second active parallel region */
inner_num = nag_omp_get_num_threads();
#ifdef _OPENMP
#pragma omp atomic
#endif
total_3++;
}
#ifdef _OPENMP
#pragma omp master
#endif
{
printf(" No. threads in 2nd parallel region:");
}
}
printf("%14" NAG_IFMT "\n", inner_num);
printf(" Total threads: %34" NAG_IFMT "\n", total_3);
END:
return exit_status;
}