program prog implicit none integer, parameter :: x_min = -20, x_max = 20 integer, parameter :: y_min = -20, y_max = 20 integer, parameter :: z_min = -20, z_max = 20 real(8), parameter :: step = 0.1_8 real(8) :: r, sum real(8) :: x,y,z real(8) :: t0, t1 call cpu_time(t0) r = 0.0_8 sum = 0.0_8 do x = x_min, x_max, step do y = y_min, y_max, step do z = z_min, z_max, step r = sqrt(x*x + y*y + z*z) sum = sum + exp(-r)*exp(-r) end do end do end do call cpu_time(t1) write(*,*) sum-1 write(*,*) t1-t0 read * end program prog |