X-Git-Url: https://svn.cri.ensmp.fr/git/Faustine.git/blobdiff_plain/440ca0ba93966e89b68dc54207c461afc0d56264..a891a827a9bad83d44164ffdd7b28f070c439e46:/interpretor/signal.ml

diff --git a/interpretor/signal.ml b/interpretor/signal.ml
index b493b6c..ae312b0 100644
--- a/interpretor/signal.ml
+++ b/interpretor/signal.ml
@@ -32,7 +32,7 @@ class signal : int -> (time -> value_type) -> signal_type =
 		  else raise (Signal_operation "frequency not matched.") in
 	    List.fold_left check self#frequency sl
 
-	method private add_memory : int -> unit = 
+	method add_memory : int -> unit = 
 	  fun (length : int) ->
 	    assert (length >= 0);
 	    if memory_length >= length then ()
@@ -141,10 +141,11 @@ class signal : int -> (time -> value_type) -> signal_type =
 		    
 	method prefix : signal_type -> signal_type =
 	    fun (s_init : signal_type) ->
+	      let () = self#add_memory 1 in
 	      let func : time -> value_type = 
 		fun t ->
 		  if t = 0 then s_init#at 0
-		  else if t > 0 then self#at t
+		  else if t > 0 then self#at (t - 1) 
 		  else raise (Signal_operation "prefix time < 0.") in
 	      new signal self#frequency func