Some utilities for input

ocaml/atom.ml

@@ -0,0 +1,47 @@
+open Core.Std;;
+
+exception AtomError of string
+
+module Charge : sig
+  type t 
+  val to_float : t -> float
+  val to_string: t -> string 
+  val of_float : float -> t
+  val of_int   : int -> t
+  val of_string: string -> t
+end = struct
+  type t = float
+  let to_float x = x
+  let to_string x = Float.to_string (to_float x)
+  let of_float x = x
+  let of_int   i = Float.of_int i
+  let of_string s = Float.of_string s
+end
+
+type t =
+{ element : Element.t ;
+  charge  : Charge.t ;
+  coord   : Point3d.t ;
+}
+
+let of_string s =
+  let buffer = s
+  |> String.split ~on:' '
+  |> List.filter ~f:(fun x -> x <> "")
+  in
+  match buffer with
+  | [ name; charge; x; y; z ] ->
+    { element = Element.of_string name ;
+      charge  = Charge.of_string  charge ;
+      coord   = Point3d.of_string (String.concat [x; y; z] ?sep:(Some " "))
+    }
+  | _ -> raise (AtomError s)
+;;
+  
+let to_string a =
+  [ Element.to_string a.element ;
+    Charge.to_string  a.charge ;
+    Point3d.to_string a.coord ]
+  |> String.concat ?sep:(Some "  ")
+;;
+

ocaml/point3d.ml

@@ -0,0 +1,35 @@
+open Core.Std;;
+
+type t = {
+  x : float ;
+  y : float ;
+  z : float ;
+}
+
+let of_string s =
+  let l = s
+  |> String.split ~on:' '
+  |> List.filter ~f:(fun x -> x <> "")
+  |> List.map ~f:Float.of_string
+  |> Array.of_list
+  in
+  { x = l.(0) ;
+    y = l.(1) ;
+    z = l.(2) }
+;;
+           
+
+let distance2 p1 p2 =
+  let { x=x1 ; y=y1 ; z=z1 } = p1
+  and { x=x2 ; y=y2 ; z=z2 } = p2 in
+  (x2-.x1)*.(x2-.x1) +. (y2-.y1)*.(y2-.y1) +. (z2-.z1)*.(z2-.z1) 
+;;
+
+let distance p1 p2 = sqrt (distance2 p1 p2)
+;;
+
+let to_string p =
+  let { x=x ; y=y ; z=z } = p in
+  Printf.sprintf "%f %f %f" x y z
+;;
+  

ocaml/test_atom.ml

@@ -0,0 +1,5 @@
+let test_atom = 
+  let line = "C  6.0  1.  2. 3." in
+  let atom = Atom.of_string line in
+  print_string (Atom.to_string atom)
+;;

ocaml/test_point3d.ml

@@ -0,0 +1,13 @@
+let test_point3d_1 () =
+  let input = "7.4950000 -0.1499810    0.5085570" in
+  let p3d = Point3d.of_string input in
+  print_string (Point3d.to_string p3d)
+;;
+
+let test_point3d () =
+  let p1 = Point3d.of_string "1. 2. 3." 
+  and p2 = Point3d.of_string "-2. 1. 1.5" in
+  Printf.printf "%f\n" (Point3d.distance p1 p2)
+;;
+
+test_point3d ();