let analytic(t0: f64) (time: f64): f64 =
  20.0 + (t0 - 20.0) * f64.exp(-0.07*time)

let cooling(_time: f64) (temperature: f64): f64 =
  -0.07 * (temperature-20.0)

let main(t0: f64) (a: f64) (b: f64) (h: f64): []f64 =
  let steps = i32.f64 ((b-a)/h)
  let temps = replicate steps 0.0
  let (_,temps) = loop (t,temps)=(t0,temps) for i < steps do
    let x = a + f64.i32 i * h
    let temps[i] = f64.abs(t-analytic t0 x)
    in (t + h * cooling x t,
        temps)
 in temps