mirror of
https://github.com/c-cube/sidekick.git
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wip: LIA: just relax to LRA for now
This commit is contained in:
Simon Cruanes
parent
8b78057058
commit
d4cf722d32
3 changed files with 60 additions and 582 deletions
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@ -7,8 +7,6 @@
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open Sidekick_core
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include Intf_lia
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module Linear_expr = Sidekick_simplex.Linear_expr
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module Make(A : ARG) : S with module A = A = struct
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module A = A
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module Ty = A.S.T.Ty
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@ -17,609 +15,98 @@ module Make(A : ARG) : S with module A = A = struct
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module SI = A.S.Solver_internal
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module N = A.S.Solver_internal.CC.N
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module Tag = struct
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type t =
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| By_def
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| Lit of Lit.t
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| CC_eq of N.t * N.t
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module Q = A.Q
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module Z = A.Z
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let pp out = function
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| By_def -> Fmt.string out "by-def"
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| Lit l -> Fmt.fprintf out "(@[lit %a@])" Lit.pp l
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| CC_eq (n1,n2) -> Fmt.fprintf out "(@[cc-eq@ %a@ %a@])" N.pp n1 N.pp n2
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let to_lits si = function
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| By_def -> []
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| Lit l -> [l]
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| CC_eq (n1,n2) ->
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SI.CC.explain_eq (SI.cc si) n1 n2
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end
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module SimpVar
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: Linear_expr.VAR
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with type t = A.term
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and type lit = Tag.t
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= struct
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type t = A.term
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let pp = A.S.T.Term.pp
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let compare = A.S.T.Term.compare
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type lit = Tag.t
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let pp_lit = Tag.pp
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let not_lit = function
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| Tag.Lit l -> Some (Tag.Lit (Lit.neg l))
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| _ -> None
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end
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module LE_ = Linear_expr.Make(A.Z)(SimpVar)
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module LE = LE_.Expr
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module SimpSolver = Sidekick_simplex.Make(struct
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module Z = A.Z
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module Q = A.Q
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module Var = SimpVar
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let mk_lit _ _ _ = assert false
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end)
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module Subst = SimpSolver.Subst
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module Comb_map = CCMap.Make(LE_.Comb)
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module LRA_solver = A.LRA_solver
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type state = {
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stat: Stat.t;
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proof: A.S.P.t;
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tst: T.store;
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ty_st: Ty.store;
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local_eqs: (N.t * N.t) Backtrack_stack.t; (* inferred by the congruence closure *)
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mutable encoded_le: T.t Comb_map.t; (* [le] -> var encoding [le] *)
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lra_solver: LRA_solver.state;
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(* TODO: with intsolver
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encoded_eqs: unit T.Tbl.t; (* [a=b] gets clause [a = b <=> (a >= b /\ a <= b)] *)
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needs_th_combination: unit T.Tbl.t;
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simplex: SimpSolver.t;
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gensym: A.Gensym.t;
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stat_th_comb: int Stat.counter;
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*)
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}
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let create ?(stat=Stat.create()) proof tst ty_st : state =
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let create ?(stat=Stat.create()) ~lra_solver proof tst ty_st : state =
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{ stat; proof; tst; ty_st;
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local_eqs=Backtrack_stack.create();
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encoded_le=Comb_map.empty;
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lra_solver;
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(*
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encoded_eqs=T.Tbl.create 16;
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simplex=SimpSolver.create();
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needs_th_combination=T.Tbl.create 16;
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stat_th_comb=Stat.mk_int stat "lia.th-comb";
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gensym=A.Gensym.create tst;
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*)
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}
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let push_level self =
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let push_level _self =
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(*
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Backtrack_stack.push_level self.local_eqs;
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*)
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()
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let pop_levels self n =
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let pop_levels _self _n =
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(*
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Backtrack_stack.pop_levels self.local_eqs n ~f:(fun _ -> ());
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*)
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()
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let fresh_term self ~pre ty = A.Gensym.fresh_term self.gensym ~pre ty
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let fresh_lit (self:state) ~mk_lit ~pre : Lit.t =
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let t = fresh_term ~pre self (Ty.bool self.ty_st) in
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mk_lit t
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(* turn the term into a linear expression. Apply [f] on leaves. *)
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let rec as_linexp ~f (t:T.t) : LE.t =
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let open LE.Infix in
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(* convert [t] to a real-typed term *)
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let rec conv_to_lra (self:state) (t:T.t) : T.t =
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let open Sidekick_arith_lra in
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let f = conv_to_lra self in
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let mklra = LRA_solver.A.mk_lra self.tst in
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match A.view_as_lia t with
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| LIA_other _ -> LE.monomial1 (f t)
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| LIA_pred _ | LIA_simplex_pred _ ->
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Error.errorf "type error: in linexp, LIA predicate %a" T.pp t
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| LIA_op (op, t1, t2) ->
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let t1 = as_linexp ~f t1 in
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let t2 = as_linexp ~f t2 in
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begin match op with
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| Plus -> t1 + t2
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| Minus -> t1 - t2
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end
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| LIA_mult (n, x) ->
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let t = as_linexp ~f x in
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LE.( n * t )
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| LIA_simplex_var v -> LE.monomial1 v
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| LIA_const q -> LE.of_const q
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let as_linexp_id = as_linexp ~f:CCFun.id
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let mk_le_q (le:LE_.Comb.t) : _ list =
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LE_.Comb.to_list le
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|> List.rev_map (fun (c,x) -> A.Q.of_bigint c, x)
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(* return a variable that is equal to [le_comb] in the simplex. *)
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let var_encoding_comb ~pre self (le_comb:LE_.Comb.t) : T.t =
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match LE_.Comb.as_singleton le_comb with
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| Some (c, x) when A.Z.(c = one) -> x (* trivial linexp *)
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| _ ->
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match Comb_map.find le_comb self.encoded_le with
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| x -> x (* already encoded that *)
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| exception Not_found ->
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(* new variable to represent [le_comb] *)
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let proxy = fresh_term self ~pre (A.ty_int self.tst) in
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(* TODO: define proxy *)
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self.encoded_le <- Comb_map.add le_comb proxy self.encoded_le;
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Log.debugf 50
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(fun k->k "(@[lia.encode-le@ `%a`@ :into-var %a@])" LE_.Comb.pp le_comb T.pp proxy);
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(* it's actually 0 *)
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if LE_.Comb.is_empty le_comb then (
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Log.debug 50 "(lia.encode-le.is-trivially-0)";
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SimpSolver.add_constraint
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self.simplex ~is_int:true
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~on_propagate:(fun _ ~reason:_ -> ())
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(SimpSolver.Constraint.leq proxy A.Q.zero) Tag.By_def;
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SimpSolver.add_constraint
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self.simplex ~is_int:true
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~on_propagate:(fun _ ~reason:_ -> ())
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(SimpSolver.Constraint.geq proxy A.Q.zero) Tag.By_def;
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) else (
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LE_.Comb.iter (fun v _ -> SimpSolver.add_var ~is_int:true self.simplex v) le_comb;
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SimpSolver.define self.simplex proxy (mk_le_q le_comb);
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);
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proxy
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let add_clause_lia_ ?using (module PA:SI.PREPROCESS_ACTS) lits =
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let pr = A.lemma_lia (Iter.of_list lits) PA.proof in
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let pr = match using with
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| None -> pr
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| Some using -> SI.P.lemma_rw_clause pr ~res:(Iter.of_list lits) ~using PA.proof in
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PA.add_clause lits pr
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(* look for subterms of type Real, for they will need theory combination *)
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let on_subterm (self:state) _ (t:T.t) : unit =
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Log.debugf 50 (fun k->k "(@[lia.cc-on-subterm@ %a@])" T.pp t);
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match A.view_as_lia t with
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| LIA_other _ when not (A.has_ty_int t) -> ()
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| _ ->
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if not (T.Tbl.mem self.needs_th_combination t) then (
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Log.debugf 5 (fun k->k "(@[lia.needs-th-combination@ %a@])" T.pp t);
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T.Tbl.add self.needs_th_combination t ()
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)
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let is_int_const t = match A.view_as_lia t with
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| LIA_const _ -> true
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| _ -> false
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| LIA_const n ->
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mklra @@ LRA_const (Q.of_bigint n)
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| LIA_pred (p, a, b) ->
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mklra @@ LRA_pred (p, f a, f b)
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| LIA_op (op, a, b) ->
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mklra @@ LRA_op (op, f a, f b)
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| LIA_mult (c, x) ->
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mklra @@ LRA_mult (Q.of_bigint c, f x)
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| LIA_other t ->
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mklra @@ LRA_other (A.mk_to_real self.tst t)
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(* preprocess linear expressions away *)
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let preproc_lia (self:state) si (module PA:SI.PREPROCESS_ACTS)
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(t:T.t) : (T.t * SI.proof_step Iter.t) option =
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Log.debugf 50 (fun k->k "(@[lia.preprocess@ %a@])" T.pp t);
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let tst = SI.tst si in
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(* preprocess subterm *)
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let preproc_t ~steps t =
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let u, pr = SI.preprocess_term si (module PA) t in
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CCOpt.iter (fun s -> steps := s :: !steps) pr;
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u
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in
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(* TODO: remove
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if A.has_ty_int t && not (is_int_const t) then (
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Log.debugf 10 (fun k->k "(@[lia.has-int-ty@ %a@])" T.pp t);
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SI.declare_pb_is_incomplete si;
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);
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*)
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(* tell the CC this term exists *)
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let declare_term_to_cc t =
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Log.debugf 50 (fun k->k "(@[simplex2.declare-term-to-cc@ %a@])" T.pp t);
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ignore (SI.CC.add_term (SI.cc si) t : SI.CC.N.t);
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in
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match A.view_as_lia t with
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| LIA_pred ((Eq | Neq), t1, t2) ->
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(* the equality side. *)
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let t, _ = T.abs tst t in
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if not (T.Tbl.mem self.encoded_eqs t) then (
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let u1 = A.mk_lia tst (LIA_pred (Leq, t1, t2)) in
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let u2 = A.mk_lia tst (LIA_pred (Geq, t1, t2)) in
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T.Tbl.add self.encoded_eqs t ();
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(* encode [t <=> (u1 /\ u2)] *)
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let lit_t = PA.mk_lit_nopreproc t in
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let lit_u1 = PA.mk_lit_nopreproc u1 in
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let lit_u2 = PA.mk_lit_nopreproc u2 in
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add_clause_lia_ (module PA) [SI.Lit.neg lit_t; lit_u1];
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add_clause_lia_ (module PA) [SI.Lit.neg lit_t; lit_u2];
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add_clause_lia_ (module PA)
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[SI.Lit.neg lit_u1; SI.Lit.neg lit_u2; lit_t];
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);
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None
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| LIA_pred (pred, t1, t2) ->
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let steps = ref [] in
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let l1 = as_linexp ~f:(preproc_t ~steps) t1 in
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let l2 = as_linexp ~f:(preproc_t ~steps) t2 in
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let le = LE.(l1 - l2) in
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let le_comb, le_const = LE.comb le, LE.const le in
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let le_const = A.Q.(neg @@ of_bigint le_const) in
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(* now we have [le_comb <pred> le_const] *)
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begin match LE_.Comb.as_singleton le_comb, pred with
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| None, _ ->
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(* non trivial linexp, give it a fresh name in the simplex *)
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let proxy = var_encoding_comb self ~pre:"_le" le_comb in
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let pr_def = SI.P.define_term proxy t PA.proof in
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steps := pr_def :: !steps;
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declare_term_to_cc proxy;
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let op =
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match pred with
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| Eq | Neq -> assert false (* unreachable *)
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| Leq -> S_op.Leq
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| Lt -> S_op.Lt
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| Geq -> S_op.Geq
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| Gt -> S_op.Gt
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in
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let new_t = A.mk_lia tst (LIA_simplex_pred (proxy, op, le_const)) in
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begin
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let lit = PA.mk_lit_nopreproc new_t in
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let constr = SimpSolver.Constraint.mk proxy op le_const in
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SimpSolver.declare_bound
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self.simplex ~is_int:true
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constr (Tag.Lit lit);
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end;
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Log.debugf 10 (fun k->k "(@[lia.preprocess:@ %a@ :into %a@])" T.pp t T.pp new_t);
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Some (new_t, Iter.of_list !steps)
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| Some (coeff, v), pred ->
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(* [c . v <= const] becomes a direct (rational) simplex constraint [v <= const/c] *)
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let const' = A.Q.( le_const / of_bigint coeff) in
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declare_term_to_cc v;
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let op = match pred with
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| Leq -> S_op.Leq
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| Lt -> S_op.Lt
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| Geq -> S_op.Geq
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| Gt -> S_op.Gt
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| Eq | Neq -> assert false
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in
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(* make sure to swap sides if multiplying with a negative coeff *)
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let op = if A.Z.(coeff < zero) then S_op.neg_sign op else op in
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(* normalize to get an integer coeff *)
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let new_t = A.mk_lia tst (LIA_simplex_pred (v, op, const')) in
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begin
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let lit = PA.mk_lit_nopreproc new_t in
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let constr = SimpSolver.Constraint.mk v op const' in
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SimpSolver.declare_bound self.simplex constr (Tag.Lit lit);
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end;
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Log.debugf 10 (fun k->k "lia.preprocess@ :%a@ :into %a" T.pp t T.pp new_t);
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Some (new_t, Iter.of_list !steps)
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end
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| LIA_op _ | LIA_mult _ ->
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let steps = ref [] in
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let le = as_linexp ~f:(preproc_t ~steps) t in
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let le_comb, le_const = LE.comb le, LE.const le in
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let le_const = A.Q.of_bigint le_const in
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if A.Q.(le_const = zero) then (
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(* if there is no constant, define [proxy] as [proxy := le_comb] and
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return [proxy] *)
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let proxy = var_encoding_comb self ~pre:"_le" le_comb in
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begin
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let pr_def = SI.P.define_term proxy t PA.proof in
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steps := pr_def :: !steps;
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end;
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declare_term_to_cc proxy;
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Some (proxy, Iter.of_list !steps)
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) else (
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(* a bit more complicated: we cannot just define [proxy := le_comb]
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because of the coefficient.
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Instead we assert [proxy - le_comb = le_const] using a secondary
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variable [proxy2 := le_comb - proxy]
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and asserting [proxy2 = -le_const] *)
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let proxy = fresh_term self ~pre:"_le" (T.ty t) in
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begin
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let pr_def = SI.P.define_term proxy t PA.proof in
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steps := pr_def :: !steps;
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end;
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let proxy2 = fresh_term self ~pre:"_le_diff" (T.ty t) in
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let pr_def2 =
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SI.P.define_term proxy (A.mk_lia tst (LIA_op (Minus, t, proxy))) PA.proof
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in
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SimpSolver.add_var self.simplex proxy;
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LE_.Comb.iter (fun v _ -> SimpSolver.add_var self.simplex v) le_comb;
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SimpSolver.define self.simplex proxy2
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((A.Q.minus_one, proxy) :: mk_le_q le_comb);
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Log.debugf 50
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(fun k->k "(@[lia.encode-le.with-offset@ %a@ :var %a@ :diff-var %a@])"
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LE_.Comb.pp le_comb T.pp proxy T.pp proxy2);
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declare_term_to_cc proxy;
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declare_term_to_cc proxy2;
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add_clause_lia_ ~using:Iter.(return pr_def2) (module PA) [
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PA.mk_lit_nopreproc (A.mk_lia tst (LIA_simplex_pred (proxy2, Leq, A.Q.neg le_const)))
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];
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add_clause_lia_ ~using:Iter.(return pr_def2) (module PA) [
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PA.mk_lit_nopreproc (A.mk_lia tst (LIA_simplex_pred (proxy2, Geq, A.Q.neg le_const)))
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];
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Some (proxy, Iter.of_list !steps)
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)
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| LIA_other t when A.has_ty_int t -> None
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| LIA_const _ | LIA_simplex_pred _ | LIA_simplex_var _ | LIA_other _ ->
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None
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let simplify (self:state) (_recurse:_) (t:T.t) : (T.t * SI.proof_step Iter.t) option =
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let proof_eq t u =
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A.lemma_lia
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(Iter.return (SI.Lit.atom self.tst (A.mk_eq self.tst t u))) self.proof
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in
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let proof_bool t ~sign:b =
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let lit = SI.Lit.atom ~sign:b self.tst t in
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A.lemma_lia (Iter.return lit) self.proof
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in
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match A.view_as_lia t with
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| LIA_op _ | LIA_mult _ ->
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let le = as_linexp_id t in
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if LE.is_const le then (
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let c = LE.const le in
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let u = A.mk_lia self.tst (LIA_const c) in
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let pr = proof_eq t u in
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Some (u, Iter.return pr)
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) else None
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| LIA_pred (pred, l1, l2) ->
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let le = LE.(as_linexp_id l1 - as_linexp_id l2) in
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if LE.is_const le then (
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let c = LE.const le in
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let is_true = match pred with
|
||||
| Leq -> A.Z.(c <= zero)
|
||||
| Geq -> A.Z.(c >= zero)
|
||||
| Lt -> A.Z.(c < zero)
|
||||
| Gt -> A.Z.(c > zero)
|
||||
| Eq -> A.Z.(c = zero)
|
||||
| Neq -> A.Z.(c <> zero)
|
||||
in
|
||||
let u = A.mk_bool self.tst is_true in
|
||||
let pr = proof_bool t ~sign:is_true in
|
||||
Some (u, Iter.return pr)
|
||||
) else None
|
||||
| _ -> None
|
||||
|
||||
let on_propagate_ si acts lit ~reason =
|
||||
match lit with
|
||||
| Tag.Lit lit ->
|
||||
(* TODO: more detailed proof certificate *)
|
||||
SI.propagate si acts lit
|
||||
~reason:(fun() ->
|
||||
let lits = CCList.flat_map (Tag.to_lits si) reason in
|
||||
let pr = A.lemma_lia Iter.(cons lit (of_list lits)) (SI.proof si) in
|
||||
CCList.flat_map (Tag.to_lits si) reason, pr)
|
||||
| _ -> ()
|
||||
|
||||
(* raise conflict from certificate *)
|
||||
let fail_with_cert si acts cert : 'a =
|
||||
Profile.with1 "simplex.check-cert" SimpSolver._check_cert cert;
|
||||
let confl =
|
||||
SimpSolver.Unsat_cert.lits cert
|
||||
|> CCList.flat_map (Tag.to_lits si)
|
||||
|> List.rev_map SI.Lit.neg
|
||||
in
|
||||
let pr = A.lemma_lia (Iter.of_list confl) (SI.proof si) in
|
||||
SI.raise_conflict si acts confl pr
|
||||
|
||||
module Q_map = CCMap.Make(A.Q)
|
||||
|
||||
let check_simplex_ ~n self si acts : SimpSolver.Subst.t option =
|
||||
Log.debugf 5 (fun k->k "(lia.check-simplex-bnb@ :n %d)" n);
|
||||
let res =
|
||||
Profile.with_ "lia.simplex.solve" @@ fun () ->
|
||||
SimpSolver.check_branch_and_bound self.simplex
|
||||
~max_tree_nodes:n
|
||||
~on_propagate:(on_propagate_ si acts)
|
||||
in
|
||||
begin match res with
|
||||
| Some (SimpSolver.Sat m) -> Some m
|
||||
| Some (SimpSolver.Unsat cert) ->
|
||||
Log.debugf 10
|
||||
(fun k->k "(@[lia.check.unsat@ :cert %a@])"
|
||||
SimpSolver.Unsat_cert.pp cert);
|
||||
fail_with_cert si acts cert
|
||||
| None ->
|
||||
(* TODO: try harder? use a slow-but-complete decision procedure? *)
|
||||
SI.declare_pb_is_incomplete si;
|
||||
None
|
||||
end
|
||||
|
||||
(* partial checks is where we add literals from the trail to the
|
||||
simplex. *)
|
||||
let partial_check_ self si acts trail : unit =
|
||||
Profile.with_ "lia.partial-check" @@ fun () ->
|
||||
|
||||
let changed = ref false in
|
||||
trail
|
||||
(fun lit ->
|
||||
let sign = SI.Lit.sign lit in
|
||||
let lit_t = SI.Lit.term lit in
|
||||
Log.debugf 50 (fun k->k "(@[lia.partial-check.add@ :lit %a@ :lit-t %a@])"
|
||||
SI.Lit.pp lit T.pp lit_t);
|
||||
match A.view_as_lia lit_t with
|
||||
| LIA_simplex_pred (v, op, q) ->
|
||||
|
||||
(* need to account for the literal's sign *)
|
||||
let op = if sign then op else S_op.not_ op in
|
||||
|
||||
(* assert new constraint to Simplex *)
|
||||
let constr = SimpSolver.Constraint.mk v op q in
|
||||
Log.debugf 10
|
||||
(fun k->k "(@[lia.partial-check.assert@ %a@])"
|
||||
SimpSolver.Constraint.pp constr);
|
||||
begin
|
||||
changed := true;
|
||||
try
|
||||
SimpSolver.add_var self.simplex v;
|
||||
SimpSolver.add_constraint
|
||||
self.simplex ~is_int:true
|
||||
constr (Tag.Lit lit)
|
||||
~on_propagate:(on_propagate_ si acts);
|
||||
with SimpSolver.E_unsat cert ->
|
||||
Log.debugf 10
|
||||
(fun k->k "(@[lia.partial-check.unsat@ :cert %a@])"
|
||||
SimpSolver.Unsat_cert.pp cert);
|
||||
fail_with_cert si acts cert
|
||||
end
|
||||
| _ -> ());
|
||||
|
||||
(* incremental check *)
|
||||
if !changed then (
|
||||
ignore (check_simplex_ ~n:2 self si acts : SimpSolver.Subst.t option);
|
||||
);
|
||||
()
|
||||
|
||||
let add_local_eq (self:state) si acts n1 n2 : unit =
|
||||
Log.debugf 20 (fun k->k "(@[lia.add-local-eq@ %a@ %a@])" N.pp n1 N.pp n2);
|
||||
let t1 = N.term n1 in
|
||||
let t2 = N.term n2 in
|
||||
let t1, t2 = if T.compare t1 t2 > 0 then t2, t1 else t1, t2 in
|
||||
|
||||
let le = LE.(as_linexp_id t1 - as_linexp_id t2) in
|
||||
let le_comb, le_const = LE.comb le, LE.const le in
|
||||
let le_const = A.Z.neg le_const in
|
||||
|
||||
let v = var_encoding_comb ~pre:"le_local_eq" self le_comb in
|
||||
let lit = Tag.CC_eq (n1,n2) in
|
||||
begin
|
||||
try
|
||||
let c1 = SimpSolver.Constraint.geq v (A.Q.of_bigint le_const) in
|
||||
SimpSolver.add_constraint self.simplex ~is_int:true c1 lit
|
||||
~on_propagate:(on_propagate_ si acts);
|
||||
let c2 = SimpSolver.Constraint.leq v (A.Q.of_bigint le_const) in
|
||||
SimpSolver.add_constraint self.simplex ~is_int:true c2 lit
|
||||
~on_propagate:(on_propagate_ si acts);
|
||||
with SimpSolver.E_unsat cert ->
|
||||
fail_with_cert si acts cert
|
||||
end;
|
||||
()
|
||||
|
||||
(* theory combination: add decisions [t=u] whenever [t] and [u]
|
||||
have the same value in [subst] and both occur under function symbols *)
|
||||
let do_th_combination (self:state) si acts (subst:Subst.t) : unit =
|
||||
Log.debug 5 "(lia.do-th-combinations)";
|
||||
let n_th_comb = T.Tbl.keys self.needs_th_combination |> Iter.length in
|
||||
if n_th_comb > 0 then (
|
||||
Log.debugf 5
|
||||
(fun k->k "(@[lia.needs-th-combination@ :n-lits %d@])" n_th_comb);
|
||||
Log.debugf 50
|
||||
(fun k->k "(@[lia.needs-th-combination@ :terms [@[%a@]]@])"
|
||||
(Util.pp_iter @@ Fmt.within "`" "`" T.pp) (T.Tbl.keys self.needs_th_combination));
|
||||
);
|
||||
|
||||
(* theory combination: for [t1,t2] terms in [self.needs_th_combination]
|
||||
that have same value, but are not provably equal, push
|
||||
decision [t1=t2] into the SAT solver. *)
|
||||
begin
|
||||
let by_val: T.t list Q_map.t =
|
||||
T.Tbl.keys self.needs_th_combination
|
||||
|> Iter.map (fun t -> Subst.eval subst t, t)
|
||||
|> Iter.fold
|
||||
(fun m (q,t) ->
|
||||
let l = Q_map.get_or ~default:[] q m in
|
||||
Q_map.add q (t::l) m)
|
||||
Q_map.empty
|
||||
| LIA_pred _ ->
|
||||
(* perform LRA relaxation *)
|
||||
let u = conv_to_lra self t in
|
||||
let pr =
|
||||
let lits = [Lit.atom ~sign:false self.tst t; Lit.atom self.tst u] in
|
||||
A.lemma_relax_to_lra Iter.(of_list lits) self.proof
|
||||
in
|
||||
Q_map.iter
|
||||
(fun _q ts ->
|
||||
begin match ts with
|
||||
| [] | [_] -> ()
|
||||
| ts ->
|
||||
(* several terms! see if they are already equal *)
|
||||
CCList.diagonal ts
|
||||
|> List.iter
|
||||
(fun (t1,t2) ->
|
||||
Log.debugf 50
|
||||
(fun k->k "(@[lia.th-comb.check-pair[val=%a]@ %a@ %a@])"
|
||||
A.Q.pp _q T.pp t1 T.pp t2);
|
||||
assert(SI.cc_mem_term si t1);
|
||||
assert(SI.cc_mem_term si t2);
|
||||
(* if both [t1] and [t2] are relevant to the congruence
|
||||
closure, and are not equal in it yet, add [t1=t2] as
|
||||
the next decision to do *)
|
||||
if not (SI.cc_are_equal si t1 t2) then (
|
||||
Log.debug 50 "lia.th-comb.must-decide-equal";
|
||||
Stat.incr self.stat_th_comb;
|
||||
Profile.instant "lia.th-comb-assert-eq";
|
||||
Some (u, Iter.return pr)
|
||||
|
||||
let t = A.mk_eq (SI.tst si) t1 t2 in
|
||||
let lit = SI.mk_lit si acts t in
|
||||
SI.push_decision si acts lit
|
||||
)
|
||||
)
|
||||
end)
|
||||
by_val;
|
||||
()
|
||||
end;
|
||||
()
|
||||
|
||||
let final_check_ (self:state) si (acts:SI.theory_actions) (_trail:_ Iter.t) : unit =
|
||||
Log.debug 5 "(th-lia.final-check)";
|
||||
Profile.with_ "lia.final-check" @@ fun () ->
|
||||
|
||||
(* add congruence closure equalities *)
|
||||
Backtrack_stack.iter self.local_eqs
|
||||
~f:(fun (n1,n2) -> add_local_eq self si acts n1 n2);
|
||||
|
||||
(* TODO: jiggle model to reduce the number of variables that
|
||||
have the same value *)
|
||||
begin match check_simplex_ ~n:15 self si acts with
|
||||
| Some model ->
|
||||
Log.debugf 20 (fun k->k "(@[lia.model@ %a@])" SimpSolver.Subst.pp model);
|
||||
Log.debug 5 "(lia: solver returns SAT)";
|
||||
do_th_combination self si acts model;
|
||||
| None ->
|
||||
() (* TODO: find a cut? *)
|
||||
end;
|
||||
()
|
||||
|
||||
(* raise conflict from certificate *)
|
||||
let fail_with_cert si acts cert : 'a =
|
||||
Profile.with1 "simplex.check-cert" SimpSolver._check_cert cert;
|
||||
let confl =
|
||||
SimpSolver.Unsat_cert.lits cert
|
||||
|> CCList.flat_map (Tag.to_lits si)
|
||||
|> List.rev_map SI.Lit.neg
|
||||
in
|
||||
let pr = A.lemma_lia (Iter.of_list confl) (SI.proof si) in
|
||||
SI.raise_conflict si acts confl pr
|
||||
|
||||
let on_propagate_ si acts lit ~reason =
|
||||
match lit with
|
||||
| Tag.Lit lit ->
|
||||
(* TODO: more detailed proof certificate *)
|
||||
SI.propagate si acts lit
|
||||
~reason:(fun() ->
|
||||
let lits = CCList.flat_map (Tag.to_lits si) reason in
|
||||
let pr = A.lemma_lia Iter.(cons lit (of_list lits)) (SI.proof si) in
|
||||
CCList.flat_map (Tag.to_lits si) reason, pr)
|
||||
| _ -> ()
|
||||
| LIA_other t when A.has_ty_int t ->
|
||||
SI.declare_pb_is_incomplete si;
|
||||
None
|
||||
| LIA_const _ | LIA_op _ | LIA_mult _ ->
|
||||
SI.declare_pb_is_incomplete si;
|
||||
None (* TODO: theory combination?*)
|
||||
| LIA_other _ ->
|
||||
None
|
||||
|
||||
let create_and_setup si =
|
||||
Log.debug 2 "(th-lia.setup)";
|
||||
let stat = SI.stats si in
|
||||
let st = create ~stat (SI.proof si) (SI.tst si) (SI.ty_st si) in
|
||||
let lra = match SI.Registry.get (SI.registry si) LRA_solver.k_state with
|
||||
| None -> Error.errorf "LIA: cannot find LRA, is it registered?"
|
||||
| Some st -> st
|
||||
in
|
||||
let st = create ~stat ~lra_solver:lra
|
||||
(SI.proof si) (SI.tst si) (SI.ty_st si) in
|
||||
|
||||
SI.add_simplifier si (simplify st);
|
||||
SI.on_preprocess si (preproc_lia st);
|
||||
SI.on_cc_is_subterm si (on_subterm st);
|
||||
SI.on_final_check si (final_check_ st);
|
||||
SI.on_partial_check si (partial_check_ st);
|
||||
SI.on_cc_post_merge si
|
||||
(fun _ _ n1 n2 ->
|
||||
if A.has_ty_int (N.term n1) then (
|
||||
Backtrack_stack.push st.local_eqs (n1, n2)
|
||||
));
|
||||
st
|
||||
|
||||
let theory =
|
||||
|
|
|
|||
|
|
@ -3,4 +3,4 @@
|
|||
(public_name sidekick.arith-lia)
|
||||
(synopsis "Solver for LIA (integer arithmetic)")
|
||||
(flags :standard -warn-error -a+8 -w -32 -open Sidekick_util)
|
||||
(libraries containers sidekick.core sidekick.arith sidekick.simplex))
|
||||
(libraries containers sidekick.core sidekick.arith sidekick.arith-lra))
|
||||
|
|
|
|||
|
|
@ -13,8 +13,6 @@ type ('num, 'real, 'a) lia_view =
|
|||
| LIA_op of op * 'a * 'a
|
||||
| LIA_mult of 'num * 'a
|
||||
| LIA_const of 'num
|
||||
| LIA_simplex_var of 'a (* an opaque variable *)
|
||||
| LIA_simplex_pred of 'a * S_op.t * 'real (* an atomic constraint *)
|
||||
| LIA_other of 'a
|
||||
|
||||
let map_view f (l:_ lia_view) : _ lia_view =
|
||||
|
|
@ -23,8 +21,6 @@ let map_view f (l:_ lia_view) : _ lia_view =
|
|||
| LIA_op (p, a, b) -> LIA_op (p, f a, f b)
|
||||
| LIA_mult (n,a) -> LIA_mult (n, f a)
|
||||
| LIA_const q -> LIA_const q
|
||||
| LIA_simplex_var v -> LIA_simplex_var (f v)
|
||||
| LIA_simplex_pred (v, op, q) -> LIA_simplex_pred (f v, op, q)
|
||||
| LIA_other x -> LIA_other (f x)
|
||||
end
|
||||
|
||||
|
|
@ -34,6 +30,12 @@ module type ARG = sig
|
|||
module Z : INT
|
||||
module Q : RATIONAL with type bigint = Z.t
|
||||
|
||||
(* pass a LRA solver as parameter *)
|
||||
module LRA_solver :
|
||||
Sidekick_arith_lra.S
|
||||
with type A.Q.t = Q.t
|
||||
and module A.S = S
|
||||
|
||||
type term = S.T.Term.t
|
||||
type ty = S.T.Ty.t
|
||||
|
||||
|
|
@ -58,18 +60,7 @@ module type ARG = sig
|
|||
|
||||
val lemma_lia : S.Lit.t Iter.t -> S.P.proof_rule
|
||||
|
||||
module Gensym : sig
|
||||
type t
|
||||
|
||||
val create : S.T.Term.store -> t
|
||||
|
||||
val tst : t -> S.T.Term.store
|
||||
|
||||
val copy : t -> t
|
||||
|
||||
val fresh_term : t -> pre:string -> S.T.Ty.t -> term
|
||||
(** Make a fresh term of the given type *)
|
||||
end
|
||||
val lemma_relax_to_lra : S.Lit.t Iter.t -> S.P.proof_rule
|
||||
end
|
||||
|
||||
module type S = sig
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue