PRACE NPT

      Subroutine datgen( arr, ari, m, n )

! ----------------------------------------------------------------------

! --- Routine 'datgen' generates the test data for the FFT:

!     one complete cosine cycle in the Real part of the data.

!     Zero in the imaginary part of the data.

! ----------------------------------------------------------------------

      Use              mpi_module

      Use              numerics

      Integer       :: m, n

      Real(l_)      :: arr(0:m-1,0:n-1), ari(0:m-1,0:n-1)

      Integer       :: nbase, nc

      Real(l_)      :: arg, fac

! ----------------------------------------------------------------------

      nc    = n*nodes

      fac   = 8.0_l_*Atan( 1.0_l_ )/( 1.0_l_*m*nc )

      nbase = me*n

      Do i = 0, n - 1

         Do j = 0, m - 1

            arg      = ( j*nc + nbase + i )*fac

            arr(j,i) = Cos( arg )

            ari(j,i) = 0.0_l_

         End Do

      End Do

! ----------------------------------------------------------------------

      End Subroutine datgen