added interface files and a few changes for clarity

Makefile

@@ -1,5 +1,5 @@
 build:
-	ocamlfind ocamlopt -package batteries -linkpkg -o football lanczos.ml bessel.ml skellam.ml
+	ocamlfind ocamlopt -package batteries -linkpkg -o football lanczos.mli bessel.mli lanczos.ml bessel.ml skellam.ml
 
 clean:
 	rm *.cm* *.o football 

bessel.ml

@@ -1,24 +1,23 @@
 let factorial n =
-  let rec f n a =
+  let rec fact_aux n a =
     match n with
       | 0 -> a
-      | _ -> f (n-1) (n*a)
+      | _ -> fact_aux (n-1) (n*a)
   in
-    f n 1
+    fact_aux n 1
 
 let mod_bessel_first m a =
   (1. /. ((float (factorial m)) *. (Lanczos.gamma (float (m + a + 1)))))
 
 let mod_bessel_second m x a =
-  x /. 2. ** (float (2 * m + a))
+  (x /. 2.) ** (float (2 * m + a))
 
 let mod_bessel m a x =
   (mod_bessel_first m a) *. (mod_bessel_second m x a)
 
 let run_mod_bessel a x =
   let range = (BatList.of_enum (BatEnum.range 0 ~until:50)) in
   let ans_list = BatList.map (fun m -> mod_bessel m a x) range in
-    (*List.iter (fun x -> print_endline (string_of_float x)) ans_list;*)
     List.fold_left (+.) 0. ans_list
 
 

bessel.mli

@@ -0,0 +1 @@
+val run_mod_bessel : int -> float -> float

lanczos.mli

@@ -0,0 +1,2 @@
+val gamma : float -> float
+val e : float

skellam.ml

@@ -1,10 +1,33 @@
+let home_team_gpm = (float_of_string Sys.argv.(1))
+let away_team_gpm = (float_of_string Sys.argv.(2))
+
 let skellam k u1 u2 =
   let first = Lanczos.e ** -.(u1 +. u2) in
   let second = (u1 /. u2) ** ((float k) /. 2.) in
   let third = 2. *. sqrt (u1 +. u2) in
     first *. second *. (Bessel.run_mod_bessel (abs k) third)
 
+let cartesian_product xs ys =
+  List.rev 
+  (List.fold_left (fun acc x ->
+    List.fold_left (fun acc y ->
+      (x,y) :: acc)
+    acc ys)
+  [] xs)
+
+let run_prediction = function
+  (home, away) -> skellam (home-away) home_team_gpm away_team_gpm
+
+let print_predictions pred scores =
+  match scores with
+    (home, away) ->
+      let home_str = string_of_int home in
+      let away_str = string_of_int away in
+      let pred_str = string_of_float pred in
+        print_endline (home_str ^ " - " ^ away_str ^ " --> " ^ pred_str)
+
 let _ =
-  let blah = -1 in 
-  let output = skellam blah 1.5 2.0 in
-    print_endline (string_of_float output)
+  let range = BatList.of_enum (BatEnum.range 0 ~until:5) in 
+  let scores = cartesian_product range range in
+  let predictions = BatList.map run_prediction scores in  
+    BatList.iter2 print_predictions predictions scores