program openmp
  implicit none
  integer                        :: k
  integer, parameter             :: n = 20
  double precision, dimension(n) :: vec
  double precision               :: min_vec

  do k = 1, n
    vec(k) = 1.0d0 / k
  end do

  min_vec = vec(1)
!$omp parallel do reduction(min: min_vec)  &
!$omp shared(vec) private(k)
  do k = 1, n
    min_vec = min(vec(k), min_vec)
  end do

  print*, 'min_vec = ', min_vec

end

!  % gfortran -fopenmp openmp.f90
!  % ./a.out
!   min_vec =   5.000000000000000E-002