Fortran Wiki
OpenMP

OpenMP is an interface for developing parallel applications on shared memory systems.

Examples

Parallel Do Loops

Parallel do loops are as simple as adding an OMP directive before and after the loop, as in the following example.

program omp_par_do
  implicit none

  integer, parameter :: n = 100
  real, dimension(n) :: dat, result
  integer :: i

  !$OMP PARALLEL DO
  do i = 1, n
     result(i) = my_function(dat(i))
  end do
  !$OMP END PARALLEL DO

contains

  function my_function(d) result(y)
    real, intent(in) :: d
    real :: y

    ! do something complex with data to calculate y
  end function my_function

end program omp_par_do

You must enable OpenMP during compilation. See the documentation for your compiler for details. With GFortran, this is accomplished with the -fopenmp flag as follows:

% gfortran -fopenmp -o omp_par_do omp_par_do.f90

External Links

• OpenMP
• Parallel Programming in Fortran 95 using OpenMP
• Parallel Computing in Fortran with OpenMP
• OpenMP Tutorial by Blaise Barney, Lawrence Livermore National Laboratory