program alloc
!$ use OMP_LIB
implicit none
real(8), dimension(:), allocatable :: T,U
integer :: Nx1 = 20, rank, Nx1min, Nx1max
integer :: tnot ! total number of threads
allocate(T(1:Nx1)) ! T is shared, allocate before PR
!$OMP PARALLEL SHARED(T) PRIVATE(U,rank,tnot,Nx1min,Nx1max)
rank = OMP_GET_THREAD_NUM () ! get the rank of current thread
tnot = OMP_GET_NUM_THREADS() ! get the total number of threads currently running this PR
Nx1min = 1 + rank * (Nx1/tnot) ! calculate the first point to be calculated by this thread
Nx1max = (rank +1) * (Nx1/tnot) ! calculate the last point to be calculated by this thread
print *, "rank :", rank, "tnot :", tnot, "min and max :", Nx1min, Nx1max
allocate(U(1:Nx1/tnot)) ! U is private, allocate inside the PR
U(1:Nx1/tnot) = rank + 10
T(Nx1min:Nx1max) = U(1:Nx1/tnot)
deallocate(U)
!$OMP END PARALLEL
print *,T
deallocate(T)
end program alloc
#include
#include
int main(int argc, char** argv)
{
int Nx1 = 20;
int rank;
int Nx1min;
int Nx1max;
int tnot;
int i;
double *T = (double*)malloc(Nx1 * sizeof(double));
double *U;
#pragma omp parallel shared(T) private(i,U,rank,tnot,Nx1min,Nx1max)
{
rank = omp_get_thread_num();
tnot = omp_get_num_threads();
Nx1min = rank * (Nx1 / tnot);
Nx1max = (rank +1) * (Nx1 / tnot) -1;
printf("rank : %d tnot : %d min and max %d %d\n", rank, tnot, Nx1min, Nx1max);
U = (double*)malloc(Nx1 * sizeof(double));
for(i = 0; i < Nx1 / tnot; i++)
U[i] = rank + 10;
for(i = Nx1min; i < Nx1max; i++)
T[i] = U[i-Nx1min];
free(U);
}
for(i = 0; i < Nx1; i++)
printf("%lf\n", T[i]);
free(T);
return 0;
}