X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_paramodulation%2Forderings.ml;h=b95593df253f1510a3cc80e6134073ebf4110eac;hb=1f6040cf168fe0cdcbe8b3c37904a2090d7083a0;hp=4e84c49b6250856ef5b00aa488bc1870f1a851d5;hpb=4aaab68e38ccafb352cc2b656e3ec3cf1ef33cab;p=helm.git

diff --git a/helm/software/components/ng_paramodulation/orderings.ml b/helm/software/components/ng_paramodulation/orderings.ml
index 4e84c49b6..b95593df2 100644
--- a/helm/software/components/ng_paramodulation/orderings.ml
+++ b/helm/software/components/ng_paramodulation/orderings.ml
@@ -11,232 +11,361 @@
 
 (* $Id$ *)
 
-(* (weight of constants, [(meta, weight_of_meta)]) *)
-type weight = int * (int * int) list;;
-
-let string_of_weight (cw, mw) =
-  let s =
-    String.concat ", "
-      (List.map (function (m, w) -> Printf.sprintf "(%d,%d)" m w) mw)
-  in
-  Printf.sprintf "[%d; %s]" cw s
-;;
-
-let weight_of_term term =
-  let vars_dict = Hashtbl.create 5 in
-  let rec aux = function
-    | Terms.Var i -> 
-        (try
-           let oldw = Hashtbl.find vars_dict i in
-           Hashtbl.replace vars_dict i (oldw+1)
-         with Not_found ->
-           Hashtbl.add vars_dict i 1);
-        0
-    | Terms.Leaf _ -> 1
-    | Terms.Node l -> List.fold_left (+) 0 (List.map aux l)
-  in
-  let w = aux term in
-  let l =
-    Hashtbl.fold (fun meta metaw resw -> (meta, metaw)::resw) vars_dict [] 
-  in
-  let compare w1 w2 = 
-    match w1, w2 with
-    | (m1, _), (m2, _) -> m2 - m1 
-  in 
-  (w, List.sort compare l) (* from the biggest meta to the smallest (0) *)
-;;
-
-let compute_clause_weight = assert false (*
-  let factor = 2 in
-  match o with
-    | Terms.Lt -> 
-	let w, m = (weight_of_term 
-	       ~consider_metas:true ~count_metas_occurrences:false right) in
-	  w + (factor * (List.length m)) ;
-    | Terms.Le -> assert false
-    | Terms.Gt -> 
-	let w, m = (weight_of_term 
-	       ~consider_metas:true ~count_metas_occurrences:false left) in
-	  w + (factor * (List.length m)) ;
-  | Terms.Ge -> assert false
-  | Terms.Eq 
-  | Terms.Incomparable -> 
-      let w1, m1 = (weight_of_term 
-	       ~consider_metas:true ~count_metas_occurrences:false right) in
-      let w2, m2 = (weight_of_term 
-	       ~consider_metas:true ~count_metas_occurrences:false left) in
-      w1 + w2 + (factor * (List.length m1)) + (factor * (List.length m2))
-*)
-;;
-
-(* returns a "normalized" version of the polynomial weight wl (with type
- * weight list), i.e. a list sorted ascending by meta number,
- * from 0 to maxmeta. wl must be sorted descending by meta number. Example:
- * normalize_weight 5 (3, [(3, 2); (1, 1)]) ->
- *      (3, [(1, 1); (2, 0); (3, 2); (4, 0); (5, 0)]) *)
-let normalize_weight maxmeta (cw, wl) =
-  let rec aux = function
-    | 0 -> []
-    | m -> (m, 0)::(aux (m-1))
-  in
-  let tmpl = aux maxmeta in
-  let wl =
-    List.sort
-      (fun (m, _) (n, _) -> Pervasives.compare m n)
-      (List.fold_left
-         (fun res (m, w) -> (m, w)::(List.remove_assoc m res)) tmpl wl)
-  in
-  (cw, wl)
-;;
+type aux_comparison = XEQ | XLE | XGE | XLT | XGT | XINCOMPARABLE
 
+module Orderings (B : Terms.Blob) = struct
 
-let normalize_weights (cw1, wl1) (cw2, wl2) =
-  let rec aux wl1 wl2 =
-    match wl1, wl2 with
-    | [], [] -> [], []
-    | (m, w)::tl1, (n, w')::tl2 when m = n ->
-        let res1, res2 = aux tl1 tl2 in
-        (m, w)::res1, (n, w')::res2
-    | (m, w)::tl1, ((n, w')::_ as wl2) when m < n ->
-        let res1, res2 = aux tl1 wl2 in
-        (m, w)::res1, (m, 0)::res2
-    | ((m, w)::_ as wl1), (n, w')::tl2 when m > n ->
-        let res1, res2 = aux wl1 tl2 in
-        (n, 0)::res1, (n, w')::res2
-    | [], (n, w)::tl2 ->
-        let res1, res2 = aux [] tl2 in
-        (n, 0)::res1, (n, w)::res2
-    | (m, w)::tl1, [] ->
-        let res1, res2 = aux tl1 [] in
-        (m, w)::res1, (m, 0)::res2
-    | _, _ -> assert false
-  in
-  let cmp (m, _) (n, _) = compare m n in
-  let wl1, wl2 = aux (List.sort cmp wl1) (List.sort cmp wl2) in
-  (cw1, wl1), (cw2, wl2)
-;;
+  type weight = int * (int * int) list;;
+  
+  let string_of_weight (cw, mw) =
+    let s =
+      String.concat ", "
+        (List.map (function (m, w) -> Printf.sprintf "(%d,%d)" m w) mw)
+    in
+    Printf.sprintf "[%d; %s]" cw s
+  ;;
+  
+  let weight_of_term term =
+    let vars_dict = Hashtbl.create 5 in
+    let rec aux = function
+      | Terms.Var i -> 
+          (try
+             let oldw = Hashtbl.find vars_dict i in
+             Hashtbl.replace vars_dict i (oldw+1)
+           with Not_found ->
+             Hashtbl.add vars_dict i 1);
+          0
+      | Terms.Leaf _ -> 1
+      | Terms.Node l -> List.fold_left (+) 0 (List.map aux l)
+    in
+    let w = aux term in
+    let l =
+      Hashtbl.fold (fun meta metaw resw -> (meta, metaw)::resw) vars_dict [] 
+    in
+    let compare w1 w2 = 
+      match w1, w2 with
+      | (m1, _), (m2, _) -> m1 - m2
+    in 
+    (w, List.sort compare l) (* from the smallest meta to the bigest *)
+  ;;
+  
+  let compute_unit_clause_weight (_,l, _, _) = 
+    let weight_of_polynomial w m =
+      let factor = 2 in      
+      w + factor * List.fold_left (fun acc (_,occ) -> acc+occ) 0 m
+    in
+    match l with
+    | Terms.Predicate t -> 
+        let w, m = weight_of_term t in 
+        weight_of_polynomial w m
+    | Terms.Equation (_,x,_,Terms.Lt) 
+    | Terms.Equation (x,_,_,Terms.Gt) ->
+        let w, m = weight_of_term x in 
+        weight_of_polynomial w m
+    | Terms.Equation (l,r,_,Terms.Eq) 
+    | Terms.Equation (l,r,_,Terms.Incomparable) ->
+        let wl, ml = weight_of_term l in 
+        let wr, mr = weight_of_term r in 
+        weight_of_polynomial (wl+wr) (ml@mr)
+  ;;
 
-(* Riazanov: 3.1.5 pag 38 *)
-(* TODO: optimize early detection of Terms.Incomparable case *)
-let compare_weights (h1, w1) (h2, w2) =
-  let res, diffs =
-    try
-      List.fold_left2
-        (fun ((lt, eq, gt), diffs) w1 w2 ->
-           match w1, w2 with
-           | (meta1, w1), (meta2, w2) when meta1 = meta2 ->
-               let diffs = (w1 - w2) + diffs in 
-               let r = compare w1 w2 in
-               if r < 0 then (lt+1, eq, gt), diffs
-               else if r = 0 then (lt, eq+1, gt), diffs
-               else (lt, eq, gt+1), diffs
-           | _ -> assert false)
-        ((0, 0, 0), 0) w1 w2
-    with Invalid_argument _ -> assert false
-  in
-  let hdiff = h1 - h2 in 
-  match res with
-  | (0, _, 0) ->
-      if hdiff < 0 then Terms.Lt
-      else if hdiff > 0 then Terms.Gt
-      else Terms.Eq 
-  | (m, _, 0) ->
-      if hdiff <= 0 then Terms.Lt
-      else if (- diffs) >= hdiff then Terms.Le else Terms.Incomparable
-  | (0, _, m) ->
-      if hdiff >= 0 then Terms.Gt
-      else if diffs >= (- hdiff) then Terms.Ge else Terms.Incomparable
-  | (m, _, n) when m > 0 && n > 0 -> Terms.Incomparable
-  | _ -> assert false 
-;;
+let compute_goal_weight (_,l, _, _) = 
+    let weight_of_polynomial w m =
+      let factor = 2 in      
+      w + factor * List.fold_left (fun acc (_,occ) -> acc+occ) 0 m
+    in
+    match l with
+    | Terms.Predicate t -> 
+        let w, m = weight_of_term t in 
+        weight_of_polynomial w m
+    | Terms.Equation (l,r,_,_) ->
+        let wl, ml = weight_of_term l in 
+        let wr, mr = weight_of_term r in 
+	let wl = weight_of_polynomial wl ml in
+	let wr = weight_of_polynomial wr mr in
+	  - (abs (wl-wr))
+  ;;
+  
+  (* Riazanov: 3.1.5 pag 38 *)
+(* Compare weights normalized in a new way :
+ * Variables should be sorted from the lowest index to the highest
+ * Variables which do not occur in the term should not be present
+ * in the normalized polynomial
+ *)
+  let compare_weights (h1, w1) (h2, w2) =
+    let rec aux hdiff (lt, gt) diffs w1 w2 =
+      match w1, w2 with
+	| ((var1, w1)::tl1) as l1, (((var2, w2)::tl2) as l2) ->
+	    if var1 = var2 then
+	      let diffs = (w1 - w2) + diffs in
+	      let r = compare w1 w2 in
+	      let lt = lt or (r < 0) in
+	      let gt = gt or (r > 0) in
+		if lt && gt then XINCOMPARABLE else
+		  aux hdiff (lt, gt) diffs tl1 tl2
+	    else if var1 < var2 then
+	      if lt then XINCOMPARABLE else
+		aux hdiff (false,true) (diffs+w1) tl1 l2	
+	    else
+	      if gt then XINCOMPARABLE else
+		aux hdiff (true,false) (diffs-w2) l1 tl2
+	| [], (_,w2)::tl2 ->
+	    if gt then XINCOMPARABLE else
+	      aux hdiff (true,false) (diffs-w2) [] tl2
+	| (_,w1)::tl1, [] ->
+	    if lt then XINCOMPARABLE else
+	      aux hdiff (false,true) (diffs+w1) tl1 []
+	| [], [] ->
+	    if lt then
+	      if hdiff <= 0 then XLT
+              else if (- diffs) >= hdiff then XLE else XINCOMPARABLE
+	    else if gt then
+	      if hdiff >= 0 then XGT
+              else if diffs >= (- hdiff) then XGE else XINCOMPARABLE
+	    else
+	      if hdiff < 0 then XLT
+	      else if hdiff > 0 then XGT
+              else XEQ
+    in
+      aux (h1-h2) (false,false) 0 w1 w2
+  ;;
+  
+  (* Riazanov: p. 40, relation >>> 
+   * if head_only=true then it is not >>> but helps case 2 of 3.14 p 39 *)
+  let rec aux_ordering ?(head_only=false) t1 t2 =
+    match t1, t2 with
+    (* We want to discard any identity equality. *
+     * If we give back XEQ, no inference rule    *
+     * will be applied on this equality          *)
+    | Terms.Var i, Terms.Var j when i = j ->
+	XEQ
+    (* 1. *)
+    | Terms.Var _, _
+    | _, Terms.Var _ -> XINCOMPARABLE
+    (* 2.a *)
+    | Terms.Leaf a1, Terms.Leaf a2 -> 
+        let cmp = B.compare a1 a2 in
+        if cmp = 0 then XEQ else if cmp < 0 then XLT else XGT
+    | Terms.Leaf _, Terms.Node _ -> XLT
+    | Terms.Node _, Terms.Leaf _ -> XGT
+    (* 2.b *)
+    | Terms.Node l1, Terms.Node l2 ->
+        let rec cmp t1 t2 =
+          match t1, t2 with
+          | [], [] -> XEQ
+          | _, [] -> XGT
+          | [], _ -> XLT
+          | hd1::tl1, hd2::tl2 ->
+              let o = aux_ordering ~head_only hd1 hd2 in
+              if o = XEQ && not head_only then cmp tl1 tl2 else o
+        in
+        cmp l1 l2
+  ;;
+  
+  (* Riazanov: p. 40, relation >_n *)
+  let nonrec_kbo t1 t2 =
+    let w1 = weight_of_term t1 in
+    let w2 = weight_of_term t2 in
+    match compare_weights w1 w2 with
+    | XLE ->  (* this is .> *)
+        if aux_ordering t1 t2 = XLT then XLT else XINCOMPARABLE
+    | XGE -> 
+        if aux_ordering t1 t2 = XGT then XGT else XINCOMPARABLE
+    | XEQ -> aux_ordering t1 t2
+    | res -> res
+  ;;
+  
+  (* Riazanov: p. 38, relation > *)
+  let rec kbo t1 t2 =
+    let aux = aux_ordering ~head_only:true in
+    let rec cmp t1 t2 =
+      match t1, t2 with
+      | [], [] -> XEQ
+      | _, [] -> XGT
+      | [], _ -> XLT
+      | hd1::tl1, hd2::tl2 ->
+          let o = kbo hd1 hd2 in
+          if o = XEQ then cmp tl1 tl2
+          else o
+    in
+    let w1 = weight_of_term t1 in
+    let w2 = weight_of_term t2 in
+    let comparison = compare_weights w1 w2 in
+    match comparison with
+    | XLE ->
+        let r = aux t1 t2 in
+        if r = XLT then XLT
+        else if r = XEQ then (
+          match t1, t2 with
+          | Terms.Node (_::tl1), Terms.Node (_::tl2) ->
+              if cmp tl1 tl2 = XLT then XLT else XINCOMPARABLE
+          | _, _ -> assert false
+        ) else XINCOMPARABLE
+    | XGE ->
+        let r = aux t1 t2 in
+        if r = XGT then XGT
+        else if r = XEQ then (
+          match t1, t2 with
+          | Terms.Node (_::tl1), Terms.Node (_::tl2) ->
+              if cmp tl1 tl2 = XGT then XGT else XINCOMPARABLE
+          | _, _ ->  assert false
+        ) else XINCOMPARABLE
+    | XEQ ->
+        let r = aux t1 t2 in
+        if r = XEQ then (
+          match t1, t2 with
+          | Terms.Node (_::tl1), Terms.Node (_::tl2) -> cmp tl1 tl2
+          | _, _ ->  XINCOMPARABLE
+        ) else r 
+    | res -> res
+  ;;
 
+  let rec lpo s t =
+    let cmp a1 a2 =
+      let res = B.compare a1 a2 in
+	if res = 0 then XEQ else if res < 0 then XLT else XGT
+    in
+    match s,t with
+      | s, t when s = t ->
+	  XEQ
+      | Terms.Var _, Terms.Var _ ->
+	  XINCOMPARABLE
+      | Terms.Leaf a1, Terms.Leaf a2 ->
+	  cmp a1 a2
+      | _, Terms.Var i ->
+	  if (List.mem i (Terms.vars_of_term s)) then XGT
+	  else XINCOMPARABLE
+      | Terms.Var _, _ ->
+      (*| Terms.Leaf _, Terms.Node _ -> *)
+	  (match lpo t s with
+	    | XGT -> XLT
+	    | XLT -> XGT
+	    | o -> o)
+      (*| Terms.Node (Terms.Leaf a1::tl), Terms.Leaf a2 ->
+	  (match cmp a1 a2 with
+	    | XGT -> XGT
+	    | _ -> 
+		if List.exists (fun x -> let o = lpo x t in o=XGT || o=XEQ) tl
+		then XGT
+		else XINCOMPARABLE)*)
+      | Terms.Node (hd1::tl1), Terms.Node (hd2::tl2) ->
+(*	  let lo = List.map (lpo s) tl2 in
+	  let ro = List.map (lpo t) tl1 in
+	    if List.exists (fun x -> x=XGT || x=XEQ) lo
+	    then XGT
+	    else if List.exists (fun x -> x=XGT || x=XEQ) ro
+	    then XLT
+	    else begin
+	      match lpo hd1 hd2 with
+		| XGT -> if List.for_all (fun x -> x=XGT) lo then XGT
+		  else XINCOMPARABLE
+		| XLT -> if List.for_all (fun x -> x=XGT) ro then XLT
+		  else XINCOMPARABLE
+		| XEQ -> List.fold_left2
+		    (fun acc si ti -> if acc = XEQ then lpo si ti else acc)
+		      XEQ tl1 tl2
+		| XINCOMPARABLE -> XINCOMPARABLE
+		| _ -> assert false
+	    end*)
+	  if List.exists (fun x -> let o = lpo x t in o=XGT || o=XEQ) tl1
+	  then XGT
+	  else if List.exists (fun x -> let o=lpo s x in o=XLT || o=XEQ) tl2
+	  then XLT
+	  else begin
+	    match lpo hd1 hd2 with
+	      | XGT -> if List.for_all (fun x -> lpo s x = XGT) tl2 then XGT
+		else XINCOMPARABLE
+	      | XLT -> if List.for_all (fun x -> lpo x t = XLT) tl1 then XLT
+		else XINCOMPARABLE
+	      | XEQ -> 
+	       let lex = List.fold_left2
+		 (fun acc si ti -> if acc = XEQ then lpo si ti else acc)
+		 XEQ tl1 tl2
+	       in
+		 (match lex with
+		    | XGT ->
+			if List.for_all (fun x -> lpo s x = XGT) tl2 then XGT
+		      else XINCOMPARABLE
+		    | XLT ->
+			if List.for_all (fun x -> lpo x t = XLT) tl1 then XLT
+		      else XINCOMPARABLE
+		    | o -> o)   
+	      | XINCOMPARABLE -> XINCOMPARABLE
+	      | _ -> assert false
+	  end
+      | _,_ -> aux_ordering s t
+	    
+  ;;
 
-let rec aux_ordering t1 t2 =
+let rec lpo_old t1 t2 =
   match t1, t2 with
-  | Terms.Var _, _
-  | _, Terms.Var _ -> Terms.Incomparable
-
-  | Terms.Leaf a1, Terms.Leaf a2 -> 
-      let cmp = Pervasives.compare a1 a2 in
-      if cmp = 0 then Terms.Eq else if cmp < 0 then Terms.Lt else Terms.Gt
-
-  | Terms.Leaf _, Terms.Node _ -> Terms.Lt
-  | Terms.Node _, Terms.Leaf _ -> Terms.Gt
-
-  | Terms.Node l1, Terms.Node l2 ->
-      let rec cmp t1 t2 =
-        match t1, t2 with
-        | [], [] -> Terms.Eq
-        | _, [] -> Terms.Gt
-        | [], _ -> Terms.Lt
-        | hd1::tl1, hd2::tl2 ->
-            let o = aux_ordering hd1 hd2 in
-            if o = Terms.Eq then cmp tl1 tl2
-            else o
+  | t1, t2 when t1 = t2 -> XEQ
+  | t1, (Terms.Var m) ->
+      if List.mem m (Terms.vars_of_term t1) then XGT else XINCOMPARABLE
+  | (Terms.Var m), t2 ->
+      if List.mem m (Terms.vars_of_term t2) then XLT else XINCOMPARABLE
+  | Terms.Node (hd1::tl1), Terms.Node (hd2::tl2) -> (
+      let res =
+        let f o r t =
+          if r then true else
+            match lpo_old t o with
+            | XGT | XEQ -> true
+            | _ -> false
+        in
+        let res1 = List.fold_left (f t2) false tl1 in
+        if res1 then XGT
+        else let res2 = List.fold_left (f t1) false tl2 in
+        if res2 then XLT
+        else XINCOMPARABLE
       in
-      cmp l1 l2
-;;
-
-let nonrec_kbo t1 t2 =
-  let w1 = weight_of_term t1 in
-  let w2 = weight_of_term t2 in
-  let w1, w2 = normalize_weights w1 w2 in
-  match compare_weights w1 w2 with
-  | Terms.Le -> if aux_ordering t1 t2 = Terms.Lt then Terms.Lt else Terms.Incomparable
-  | Terms.Ge -> if aux_ordering t1 t2 = Terms.Gt then Terms.Gt else Terms.Incomparable
-  | Terms.Eq -> aux_ordering t1 t2
-  | res -> res
-;;
-
-(*
-let rec kbo t1 t2 =
-  let aux = aux_ordering ~recursion:false in
-  let w1 = weight_of_term t1
-  and w2 = weight_of_term t2 in
-  let rec cmp t1 t2 =
-    match t1, t2 with
-    | [], [] -> Terms.Eq
-    | _, [] -> Terms.Gt
-    | [], _ -> Terms.Lt
-    | hd1::tl1, hd2::tl2 ->
-        let o =
-          kbo hd1 hd2
+      if res <> XINCOMPARABLE then
+        res
+      else
+        let f o r t =
+          if not r then false else
+            match lpo_old o t with
+            | XGT -> true
+            | _ -> false
         in
-        if o = Terms.Eq then cmp tl1 tl2
-        else o
-  in
-  let w1, w2 = normalize_weights w1 w2 in
-  let comparison = compare_weights w1 w2 in
-  match comparison with
-  | Terms.Le ->
-      let r = aux t1 t2 in
-      if r = Terms.Lt then Terms.Lt
-      else if r = Terms.Eq then (
-        match t1, t2 with
-        | Cic.Appl (h1::tl1), Cic.Appl (h2::tl2) when h1 = h2 ->
-            if cmp tl1 tl2 = Terms.Lt then Terms.Lt else Terms.Incomparable
-        | _, _ ->  Terms.Incomparable
-      ) else Terms.Incomparable
-  | Terms.Ge ->
-      let r = aux t1 t2 in
-      if r = Terms.Gt then Terms.Gt
-      else if r = Terms.Eq then (
-        match t1, t2 with
-        | Cic.Appl (h1::tl1), Cic.Appl (h2::tl2) when h1 = h2 ->
-            if cmp tl1 tl2 = Terms.Gt then Terms.Gt else Terms.Incomparable
-        | _, _ ->  Terms.Incomparable
-      ) else Terms.Incomparable
-  | Terms.Eq ->
-      let r = aux t1 t2 in
-      if r = Terms.Eq then (
-        match t1, t2 with
-        | Cic.Appl (h1::tl1), Cic.Appl (h2::tl2) when h1 = h2 ->
-            cmp tl1 tl2
-        | _, _ ->  Terms.Incomparable
-      ) else r 
-  | res -> res
+        match aux_ordering hd1 hd2 with
+        | XGT ->
+            let res = List.fold_left (f t1) false tl2 in
+            if res then XGT
+            else XINCOMPARABLE
+        | XLT ->
+            let res = List.fold_left (f t2) false tl1 in
+            if res then XLT
+            else XINCOMPARABLE
+        | XEQ -> (
+            let lex_res =
+              try
+                List.fold_left2
+                  (fun r t1 t2 -> if r <> XEQ then r else lpo_old t1 t2)
+                  XEQ tl1 tl2
+              with Invalid_argument _ ->
+                XINCOMPARABLE
+            in
+            match lex_res with
+            | XGT ->
+                if List.fold_left (f t1) false tl2 then XGT
+                else XINCOMPARABLE
+            | XLT ->
+                if List.fold_left (f t2) false tl1 then XLT
+                else XINCOMPARABLE
+            | _ -> XINCOMPARABLE
+          )
+        | _ -> XINCOMPARABLE
+    )
+  | t1, t2 -> aux_ordering t1 t2
 ;;
-*)
-          
-let compare_terms = nonrec_kbo;; 
 
+  let compare_terms x y = 
+    match lpo_old x y with
+    | XINCOMPARABLE -> Terms.Incomparable
+    | XGT -> Terms.Gt
+    | XLT -> Terms.Lt
+    | XEQ -> Terms.Eq
+    | _ -> assert false
+  ;; 
+
+end