! Simple matmul example

    module mymm
    contains
    subroutine multiply_matrices( a, b, c, m )
     real, dimension(:,:) :: a,b,c
     i = 0

!$acc parallel
     do j = 1,m
         do i = 1,m
          a(i,j) = 0.0
         enddo
       do k = 1,m
         do i = 1,m
          a(i,j) = a(i,j) + b(i,k) * c(k,j)
         enddo
       enddo
     enddo
!$acc end parallel
    end subroutine
    end module