-(**
- Module: Signal
- Description: signal definition and operations.
- @author WANG Haisheng
- Created: 03/06/2013 Modified: 03/06/2013
-*)
-
-open Types;;
-open Basic;;
-open Value;;
-
-exception Signal_operation of string;;
-
-let delay_memory_length = 10000;;
-
-class signal : int -> (time -> value_type) -> signal_type =
- fun (freq_init : int) ->
- fun (func_init : time -> value_type) ->
- object (self)
- val mutable signal_func = func_init
- val mutable memory_length = 0
- method frequency = freq_init
- method at = signal_func
-
- method private check_freq : signal_type list -> int =
- fun (sl : signal_type list) ->
- let check : int -> signal_type -> int =
- fun (f : int) ->
- fun (s : signal_type) ->
- if f = s#frequency || s#frequency = 0 then f
- else if f = 0 then s#frequency
- else raise (Signal_operation "frequency not matched.") in
- List.fold_left check self#frequency sl
-
- method add_memory : int -> unit =
- fun (length : int) ->
- assert (length >= 0);
- if memory_length >= length then ()
- else
- let memory = Hashtbl.create length in
- let func : time -> value =
- fun (t : time) ->
- try Hashtbl.find memory t
- with Not_found ->
- let result = func_init t in
- let () = Hashtbl.replace memory t result in
- let () =
- if (t - length) >= 0 then
- Hashtbl.remove memory (t - length)
- else () in
- result in
- memory_length <- length;
- signal_func <- func
-
- method private delay_by : int -> time -> value =
- fun i -> fun t ->
- if (t - i) >= 0 then
- self#at (t - i)
- else if t >= 0 && (t - i) < 0 then
- (self#at 0)#zero
- else raise (Signal_operation "Delay time < 0.")
-
- method private prim1 :
- (time -> value_type) -> signal_type =
- fun (func : time -> value_type) ->
- let freq = self#frequency in
- new signal freq func
-
- method private prim2 :
- (time -> value_type -> value_type) -> signal_type -> signal_type =
- fun (func_binary : time -> value_type -> value_type) ->
- fun (s : signal_type) ->
- let freq = self#check_freq [s] in
- let func = fun t -> (func_binary t) (s#at t) in
- new signal freq func
-
- method neg = self#prim1 (fun t -> (self#at t)#neg)
- method floor = self#prim1 (fun t -> (self#at t)#floor)
- method sin = self#prim1 (fun t -> (self#at t)#sin)
- method cos = self#prim1 (fun t -> (self#at t)#cos)
- method atan = self#prim1 (fun t -> (self#at t)#atan)
- method sqrt = self#prim1 (fun t -> (self#at t)#sqrt)
- method int = self#prim1 (fun t -> (self#at t)#int)
-
- method add = self#prim2 (fun t -> (self#at t)#add)
- method sub = self#prim2 (fun t -> (self#at t)#sub)
- method mul = self#prim2 (fun t -> (self#at t)#mul)
- method div = self#prim2 (fun t -> (self#at t)#div)
- method atan2 = self#prim2 (fun t -> (self#at t)#atan2)
- method _mod = self#prim2 (fun t -> (self#at t)#_mod)
- method larger = self#prim2 (fun t -> (self#at t)#larger)
- method smaller = self#prim2 (fun t -> (self#at t)#smaller)
-
- method delay : signal_type -> signal_type =
- fun (s : signal_type) ->
- let freq = self#check_freq [s] in
- let () = self#add_memory delay_memory_length in
- let func : time -> value_type =
- fun (t : time) ->
- let i = (s#at t)#to_int in
- self#delay_by t i in
- new signal freq func
-
- method mem : signal_type =
- let freq = self#frequency in
- let () = self#add_memory 1 in
- let func = fun (t : time) -> self#delay_by t 1 in
- new signal freq func
-
- method rdtable : signal_type -> signal_type -> signal_type =
- fun (s_size : signal_type) ->
- fun (s_index : signal_type) ->
- let freq = self#check_freq [s_index] in
- let () = self#add_memory ((s_size#at 0)#to_int) in
- let func : time -> value_type = fun t ->
- self#at ((s_index#at t)#to_int) in
- new signal freq func
-
- method select2 : signal_type -> signal_type -> signal_type =
- fun s_first ->
- fun s_second ->
- let freq = self#check_freq [s_first; s_second] in
- let func : time -> value_type =
- fun t -> let i = (self#at t)#to_int in
- if i = 0 then s_first#at t
- else if i = 1 then s_second#at t
- else raise (Signal_operation "select2 index 0|1.") in
- new signal freq func
-
- method select3 :
- signal_type -> signal_type -> signal_type -> signal_type =
- fun s_first -> fun s_second -> fun s_third ->
- let freq = self#check_freq [s_first; s_second; s_third] in
- let func : time -> value_type =
- fun t -> let i = (self#at t)#to_int in
- if i = 0 then s_first#at t
- else if i = 1 then s_second#at t
- else if i = 2 then s_third#at t
- else raise (Signal_operation "select2 index 0|1.") in
- new signal freq func
-
- 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 - 1)
- else raise (Signal_operation "prefix time < 0.") in
- new signal self#frequency func
-
-
- method vectorize : signal_type -> signal_type =
- fun s_size ->
- let size = (s_size#at 0)#to_int in
- if size <= 0 then
- raise (Signal_operation "Vectorize: size <= 0.")
- else
- let freq = self#frequency / size in
- let func : time -> value_type =
- fun t ->
- let vec = fun i -> (self#at (size * t + i))#get in
- new value (Vec (new vector size vec)) in
- new signal freq func
-
-
- method serialize : signal_type =
- let size =
- match (self#at 0)#get with
- | Vec vec -> vec#size
- | _ -> raise (Signal_operation "Serialize: scalar input.") in
- let freq = self#frequency * size in
- let func : time -> value_type =
- fun t ->
- match (self#at (t/size))#get with
- | Vec vec -> new value (vec#nth (t mod size))
- | _ -> raise (Signal_operation
- "Serialize: signal type not consistent.") in
- new signal freq func
-
- method vconcat : signal_type -> signal_type =
- fun s ->
- let freq = self#check_freq [s] in
- let func : time -> value_type =
- fun t ->
- match ((self#at t)#get, (s#at t)#get) with
- | (Vec vec1, Vec vec2) ->
- let size1 = vec1#size in
- let size2 = vec2#size in
- let size = size1 + size2 in
- let vec = fun i ->
- if i < size1 then vec1#nth i
- else vec2#nth (i - size1) in
- new value (Vec (new vector size vec))
- | _ -> raise (Signal_operation "Vconcat: scalar.") in
- new signal freq func
-
- method vpick : signal_type -> signal_type =
- fun s_index ->
- let freq = self#check_freq [s_index] in
- let func : time -> value_type =
- fun t ->
- let i = (s_index#at t)#to_int in
- match (self#at t)#get with
- | Vec vec -> new value (vec#nth i)
- | _ -> raise (Signal_operation "Vpick: scalar.") in
- new signal freq func
-
- end;;
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