gcc/testsuite/gfortran.dg/interface_36.f90

   1 ! { dg-do compile }
   2 !
   3 ! PR fortran/48800
   4 !
   5 ! Contributed by Daniel Carrera
   6 !
   7      pure function runge_kutta_step(t, r_, dr, h) result(res)
   8          real, intent(in) :: t, r_(:), h
   9          real, dimension(:), allocatable :: k1, k2, k3, k4, res
  10          integer :: N
  11
  12          interface
  13              pure function dr(t, r_)  ! { dg-error "cannot have a deferred shape" }
  14                  real, intent(in) :: t, r_(:)
  15                  real :: dr(:)
  16              end function
  17          end interface
  18
  19          N = size(r_)
  20          allocate(k1(N),k2(N),k3(N),k4(N),res(N))
  21
  22          k1 = dr(t, r_)
  23          k2 = dr(t + h/2, r_ + k1*h/2)
  24          k3 = dr(t + h/2, r_ + k2*h/2)
  25          k4 = dr(t + h  , r_ + k3*h)
  26
  27          res = r_ + (k1 + 2*k2 + 2*k3 + k4) * h/6
  28      end function