(* Trigonometric functions using degrees *)

let pi = 3.14159265358979323846
let degrees_to_radians = pi /. 180.0
let radians_to_degrees = 180.0 /. pi

let deg_cos a = cos (a *. degrees_to_radians)
let deg_sin a = sin (a *. degrees_to_radians)
let deg_acos x = acos x *. radians_to_degrees
let deg_asin x = asin x *. radians_to_degrees

(* Internalization of strings (unique representatives) *)

let intern_table = (Hashtbl.create 37 : (string, string) Hashtbl.t)

let intern s =
  try
    Hashtbl.find intern_table s
  with Not_found ->
    Hashtbl.add intern_table s s; s

let fudge_factor = ref 0.0;;
let set_fudge_factor x = fudge_factor := x;;
let fudge x =
  if !fudge_factor = 0.0
  then x
  else x *. (1. -. Random.float !fudge_factor)
;;

(* positive infinity *)

let pos_infty = 1.0 /. 0.0