Fixed overflow in Boys

Notebooks/SpVec.ipynb

@@ -1746,7 +1746,7 @@
  "metadata": {
   "celltoolbar": "Raw Cell Format",
   "kernelspec": {
-   "display_name": "OCaml 4.07.1",
+   "display_name": "OCaml default",
    "language": "OCaml",
    "name": "ocaml-jupyter"
   },

Utils/Util.ml

@@ -209,29 +209,29 @@ let boys_function ~maxm t =
       let result =
         Array.init (maxm+1) (fun m -> 1. /. float_of_int (2*m+1))
       in
-      (*
-      assert (abs_float t > 1.e-10);
-      *)
-      if t <> 0. then
-        begin
+      let power_t_inv = (maxm+maxm+1)  in
+      try  
           let fmax = 
             let t_inv = sqrt (1. /. t) in
             let n = float_of_int maxm in
             let dm = 0.5 +. n in
-            let f  = (pow t_inv (maxm+maxm+1) ) in
+            let f  = (pow t_inv power_t_inv ) in
             match classify_float f with
               | FP_normal -> (incomplete_gamma dm t) *. 0.5 *. f
               | FP_zero
               | FP_subnormal -> 0.
-              | _ -> invalid_arg "zero_m overflow"
+              | _ ->
+                Printf.eprintf "t=%e\n" t;
+                Printf.eprintf "maxm=%d\n" maxm;
+                raise Exit
           in
           let emt = exp (-. t) in
           result.(maxm) <- fmax;
           for n=maxm-1 downto 0 do
             result.(n) <- ( (t+.t) *. result.(n+1) +. emt) *. result.(n)
-          done
-        end;
-      result
+          done;
+          result
+      with Exit -> result
     end