ocaml: phase 5.1 newton_sqrt.ml baseline (Newton's method, sqrt(2)*1000 = 1414)

Newton's method for square root:

  let sqrt_newton x =
    let g = ref 1.0 in
    for _ = 1 to 20 do
      g := (!g +. x /. !g) /. 2.0
    done;
    !g

20 iterations is more than enough to converge for x=2 — result is
~1.414213562. Multiplied by 1000 and int_of_float'd: 1414.

First baseline exercising:
  - for _ = 1 to N do ... done (wildcard loop variable)
  - pure float arithmetic with +. /.
  - the int_of_float truncate-toward-zero fix from iter 117

38 baseline programs total.

lib/ocaml/baseline/newton_sqrt.ml

@@ -0,0 +1,10 @@
+let sqrt_newton x =
+  let g = ref 1.0 in
+  for _ = 1 to 20 do
+    g := (!g +. x /. !g) /. 2.0
+  done;
+  !g
+
+;;
+
+int_of_float (sqrt_newton 2.0 *. 1000.0)