1! { dg-do compile } 2! 3! PR fortran/48821 4! 5! Contributed by Daniel Carrera 6! 7 8contains 9 pure subroutine rk4_vec(t, Y, dY, h) 10 real, intent(inout) :: t, Y(:) 11 real, intent(in) :: h 12 real, dimension(size(Y)) :: k1, k2, k3, k4 13 14 interface 15 pure function dY(t0, y0) 16 import :: Y 17 real, intent(in) :: t0, y0(size(Y)) 18 real :: dY(size(y0)) 19 end function 20 end interface 21 22 k1 = dY(t, Y) 23 k2 = dY(t + h/2, Y + k1*h/2) 24 k3 = dY(t + h/2, Y + k2*h/2) 25 k4 = dY(t + h , Y + k3*h) 26 27 Y = Y + (k1 + 2*k2 + 2*k3 + k4) * h/6 28 t = t + h 29 end subroutine 30end 31