src/HOL/Decision_Procs/ferrack_tac.ML
author nipkow
Wed Jun 24 09:41:14 2009 +0200 (2009-06-24)
changeset 31790 05c92381363c
parent 31302 12677a808d43
child 32740 9dd0a2f83429
permissions -rw-r--r--
corrected and unified thm names
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(*  Title:      HOL/Decision_Procs/ferrack_tac.ML
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    Author:     Amine Chaieb, TU Muenchen
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*)
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signature FERRACK_TAC =
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sig
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  val trace: bool ref
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  val linr_tac: Proof.context -> bool -> int -> tactic
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  val setup: theory -> theory
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end
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structure Ferrack_Tac =
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struct
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val trace = ref false;
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fun trace_msg s = if !trace then tracing s else ();
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val ferrack_ss = let val ths = [@{thm real_of_int_inject}, @{thm real_of_int_less_iff}, 
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				@{thm real_of_int_le_iff}]
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	     in @{simpset} delsimps ths addsimps (map (fn th => th RS sym) ths)
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	     end;
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val binarith =
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  @{thms normalize_bin_simps} @ @{thms pred_bin_simps} @ @{thms succ_bin_simps} @
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  @{thms add_bin_simps} @ @{thms minus_bin_simps} @  @{thms mult_bin_simps};
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val comp_arith = binarith @ simp_thms
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val zdvd_int = @{thm zdvd_int};
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val zdiff_int_split = @{thm zdiff_int_split};
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val all_nat = @{thm all_nat};
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val ex_nat = @{thm ex_nat};
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val number_of1 = @{thm number_of1};
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val number_of2 = @{thm number_of2};
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val split_zdiv = @{thm split_zdiv};
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val split_zmod = @{thm split_zmod};
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val mod_div_equality' = @{thm mod_div_equality'};
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val split_div' = @{thm split_div'};
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val Suc_eq_plus1 = @{thm Suc_eq_plus1};
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val imp_le_cong = @{thm imp_le_cong};
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val conj_le_cong = @{thm conj_le_cong};
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val mod_add_left_eq = @{thm mod_add_left_eq} RS sym;
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val mod_add_right_eq = @{thm mod_add_right_eq} RS sym;
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val nat_div_add_eq = @{thm div_add1_eq} RS sym;
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val int_div_add_eq = @{thm zdiv_zadd1_eq} RS sym;
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val ZDIVISION_BY_ZERO_MOD = @{thm DIVISION_BY_ZERO} RS conjunct2;
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val ZDIVISION_BY_ZERO_DIV = @{thm DIVISION_BY_ZERO} RS conjunct1;
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fun prepare_for_linr sg q fm = 
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  let
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    val ps = Logic.strip_params fm
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    val hs = map HOLogic.dest_Trueprop (Logic.strip_assums_hyp fm)
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    val c = HOLogic.dest_Trueprop (Logic.strip_assums_concl fm)
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    fun mk_all ((s, T), (P,n)) =
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      if 0 mem loose_bnos P then
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        (HOLogic.all_const T $ Abs (s, T, P), n)
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      else (incr_boundvars ~1 P, n-1)
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    fun mk_all2 (v, t) = HOLogic.all_const (fastype_of v) $ lambda v t;
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      val rhs = hs
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(*    val (rhs,irhs) = List.partition (relevant (rev ps)) hs *)
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    val np = length ps
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    val (fm',np) =  foldr (fn ((x, T), (fm,n)) => mk_all ((x, T), (fm,n)))
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      (foldr HOLogic.mk_imp c rhs, np) ps
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    val (vs, _) = List.partition (fn t => q orelse (type_of t) = HOLogic.natT)
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      (OldTerm.term_frees fm' @ OldTerm.term_vars fm');
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    val fm2 = foldr mk_all2 fm' vs
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  in (fm2, np + length vs, length rhs) end;
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(*Object quantifier to meta --*)
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fun spec_step n th = if (n=0) then th else (spec_step (n-1) th) RS spec ;
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(* object implication to meta---*)
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fun mp_step n th = if (n=0) then th else (mp_step (n-1) th) RS mp;
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fun linr_tac ctxt q i = 
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    (ObjectLogic.atomize_prems_tac i) 
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	THEN (REPEAT_DETERM (split_tac [@{thm split_min}, @{thm split_max}, @{thm abs_split}] i))
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	THEN (fn st =>
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  let
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    val g = List.nth (prems_of st, i - 1)
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    val thy = ProofContext.theory_of ctxt
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    (* Transform the term*)
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    val (t,np,nh) = prepare_for_linr thy q g
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    (* Some simpsets for dealing with mod div abs and nat*)
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    val simpset0 = Simplifier.theory_context thy HOL_basic_ss addsimps comp_arith
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    val ct = cterm_of thy (HOLogic.mk_Trueprop t)
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    (* Theorem for the nat --> int transformation *)
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   val pre_thm = Seq.hd (EVERY
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      [simp_tac simpset0 1,
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       TRY (simp_tac (Simplifier.theory_context thy ferrack_ss) 1)]
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      (trivial ct))
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    fun assm_tac i = REPEAT_DETERM_N nh (assume_tac i)
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    (* The result of the quantifier elimination *)
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    val (th, tac) = case (prop_of pre_thm) of
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        Const ("==>", _) $ (Const ("Trueprop", _) $ t1) $ _ =>
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    let val pth = linr_oracle (cterm_of thy (Pattern.eta_long [] t1))
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    in 
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          (trace_msg ("calling procedure with term:\n" ^
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             Syntax.string_of_term ctxt t1);
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           ((pth RS iffD2) RS pre_thm,
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            assm_tac (i + 1) THEN (if q then I else TRY) (rtac TrueI i)))
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    end
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      | _ => (pre_thm, assm_tac i)
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  in (rtac (((mp_step nh) o (spec_step np)) th) i 
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      THEN tac) st
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  end handle Subscript => no_tac st);
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val setup =
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  Method.setup @{binding rferrack}
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    (Args.mode "no_quantify" >> (fn q => fn ctxt =>
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      SIMPLE_METHOD' (linr_tac ctxt (not q))))
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    "decision procedure for linear real arithmetic";
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end