simon/sidekick
1
0
Fork 0
mirror of https://github.com/c-cube/sidekick.git synced 2025-12-06 03:05:31 -05:00
Code Issues Projects Releases Packages Wiki Activity Actions

wip: gc atoms and reuse them

Browse source
This commit is contained in:
Simon Cruanes 2021-09-26 21:35:34 -04:00
parent f640bd23a5
commit aaec84dfb6
No known key found for this signature in database
GPG key ID: 4AC01D0849AA62B6
1 changed files with 114 additions and 19 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

133
src/sat/Solver.ml
View file

@ -108,6 +108,8 @@ module Make(Plugin : PLUGIN)
v_reason: reason option Vec.t; (* reason for assignment *)
v_seen: Bitvec.t; (* generic temporary marker *)
v_default_polarity: Bitvec.t; (* default polarity in decisions *)
v_persistent: Bitvec.t; (* must be kept even if present in 0 clauses? *)
v_recycle_idx: VecI32.t; (* recycle variables that were gc'd *)
mutable v_count : int;
(* atoms *)
@ -118,6 +120,7 @@ module Make(Plugin : PLUGIN)
a_watched: Clause0.CVec.t Vec.t;
stat_n_atoms: int Stat.counter;
stat_gc_atoms: int Stat.counter;
(* clauses *)
c_store: cstore;
@ -131,6 +134,7 @@ module Make(Plugin : PLUGIN)
| `Big -> 4096
in
let stat_n_atoms = Stat.mk_int stat "sat.n-atoms" in
let stat_gc_atoms = Stat.mk_int stat "sat.atoms.gc" in
{ v_of_lit = Lit_tbl.create size_map;
v_level = Vec.create();
v_heap_idx = Vec.create();
@ -138,12 +142,15 @@ module Make(Plugin : PLUGIN)
v_reason = Vec.create();
v_seen = Bitvec.create();
v_default_polarity = Bitvec.create();
v_persistent = Bitvec.create();
v_recycle_idx=VecI32.create ~cap:0 ();
v_count = 0;
a_is_true=Bitvec.create();
a_form=Vec.create();
a_watched=Vec.create();
a_seen=Bitvec.create();
stat_n_atoms;
stat_gc_atoms;
c_store={
c_lits=Vec.create();
c_activity=Vec_float.create();
@ -177,6 +184,11 @@ module Make(Plugin : PLUGIN)
let[@inline] default_pol self v = Bitvec.get self.v_default_polarity (v:var:>int)
let[@inline] heap_idx self v = Vec.get self.v_heap_idx (v:var:>int)
let[@inline] set_heap_idx self v i = Vec.set self.v_heap_idx (v:var:>int) i
let[@inline] set_persistent self v b = Bitvec.set self.v_persistent (v:var:>int) b
let[@inline] persistent self v = Bitvec.get self.v_persistent (v:var:>int)
let[@inline] iter_all (self:store) ~f : unit =
for i=0 to self.v_count-1 do f (of_int_unsafe i) done
end
module Atom = struct
@ -426,32 +438,52 @@ module Make(Plugin : PLUGIN)
(* allocate new variable *)
let alloc_var_uncached_ ?default_pol:(pol=true) self (form:lit) : var =
let {v_count; v_of_lit; v_level; v_heap_idx; v_weight;
v_reason; v_seen; v_default_polarity; stat_n_atoms;
a_is_true; a_seen; a_watched; a_form; c_store=_;
v_reason; v_seen; v_default_polarity; v_persistent;
stat_n_atoms; a_is_true; a_seen; a_watched; a_form;
c_store=_; stat_gc_atoms=_; v_recycle_idx;
} = self in
let v_idx = v_count in
(* allocate index, possibly by reusing a dead one *)
let v_idx, is_new =
if VecI32.is_empty v_recycle_idx then (
let n = v_count in
self.v_count <- 1 + v_count;
n, true
) else (
VecI32.pop v_recycle_idx, false
)
in
let v = Var.of_int_unsafe v_idx in
Stat.incr stat_n_atoms;
self.v_count <- 1 + v_idx;
Lit_tbl.add v_of_lit form v;
Vec.push v_level (-1);
Vec.push v_heap_idx (-1);
Vec.push v_reason None;
Vec_float.push v_weight 0.;
Bitvec.ensure_size v_seen v_idx;
Bitvec.ensure_size v_default_polarity v_idx;
Bitvec.set v_default_polarity v_idx pol;
(* allocate new fields *)
if is_new then (
Vec.push v_level (-1);
Vec.push v_heap_idx (-1);
Vec.push v_reason None;
Vec_float.push v_weight 0.;
Bitvec.ensure_size v_seen v_idx;
Bitvec.ensure_size v_default_polarity v_idx;
Bitvec.ensure_size v_persistent v_idx;
assert (Vec.size a_form = 2 * (v:var:>int));
Bitvec.ensure_size a_is_true (2*(v:var:>int));
Bitvec.ensure_size a_seen (2*(v:var:>int));
Vec.push a_form form;
Vec.push a_watched (CVec.create ~cap:0 ());
Vec.push a_form (Lit.neg form);
Vec.push a_watched (CVec.create ~cap:0 ());
assert (Vec.size a_form = 2 * (v:var:>int));
Bitvec.ensure_size a_is_true (2*(v:var:>int));
Bitvec.ensure_size a_seen (2*(v:var:>int));
Vec.push a_form form;
Vec.push a_watched (CVec.create ~cap:0 ());
Vec.push a_form (Lit.neg form);
Vec.push a_watched (CVec.create ~cap:0 ());
) else (
Var.set_level self v (-1);
Var.set_heap_idx self v (-1);
Var.set_reason self v None;
Var.unmark self v;
Vec.set a_form (Atom.pa v:>int) form;
Vec.set a_form (Atom.na v:>int) (Lit.neg form);
);
Bitvec.set v_default_polarity v_idx pol;
assert (Vec.get a_form (Atom.of_var v:atom:>int) == form);
v
@ -470,6 +502,24 @@ module Make(Plugin : PLUGIN)
Atom.unmark self (Atom.na v);
()
(* delete variable and its atoms *)
let remove_var (self:t) (v:var) : unit =
let lit = Atom.lit self (Atom.pa v) in
Lit_tbl.remove self.v_of_lit lit;
Var.set_level self v (-1);
Var.set_heap_idx self v (-1);
Var.set_reason self v None;
Var.set_weight self v 0.;
Var.mark self v; (* mark so that GC will not GC this again *)
List.iter
(fun a ->
CVec.clear (Atom.watched self a);
Atom.set_is_true self a false;
Atom.unmark self a;
)
[Atom.pa v; Atom.na v];
VecI32.push self.v_recycle_idx (v:var:>int) (* recycle slot *)
let atom_of_var_ v same_sign : atom =
if same_sign then Atom.pa v else Atom.na v
@ -1666,6 +1716,49 @@ module Make(Plugin : PLUGIN)
(Format.pp_print_list (Atom.debug store)) !core);
!core
(* remove unused variables that are also not persistent *)
let reduce_var_db (self:t) : unit =
Log.debugf 3 (fun k->k "(@[sat.gc-atoms@])");
let alive_atoms = self.temp_atom_vec in
assert (AVec.is_empty alive_atoms);
(* mark atoms to keep *)
let mark_atom_alive (a:atom) =
let v = Atom.var a in
if not (Var.persistent self.store v) &&
not (Var.marked self.store v) then (
Var.mark self.store v;
AVec.push alive_atoms (Atom.pa v); (* always store positive atom *)
)
in
let add_atoms_of_clause (c:clause) =
Clause.iter self.store c ~f:mark_atom_alive;
in
iter_clauses_learnt_ self ~f:add_atoms_of_clause;
CVec.iter self.clauses_hyps ~f:add_atoms_of_clause;
CVec.iter self.clauses_to_add_learnt ~f:add_atoms_of_clause;
Vec.iter (fun (c,_cp) -> add_atoms_of_clause c) self.clauses_to_add_in_pool;
AVec.iter self.trail ~f:mark_atom_alive;
(* now collect dead variables *)
Var.iter_all self.store
~f:(fun v ->
if not (Var.persistent self.store v) &&
not (Var.marked self.store v) then (
(* dead var *)
Store.remove_var self.store v;
Stat.incr self.store.stat_gc_atoms;
Format.eprintf "REMOVE ATOM %a@." (Atom.debug self.store) (Atom.pa v);
));
(* cleanup *)
AVec.iter alive_atoms ~f:(fun a -> Var.unmark self.store (Atom.var a));
AVec.clear alive_atoms;
()
(* GC: remove some learnt clauses.
This works even during the proof with a non empty trail. *)
let reduce_clause_db (self:t) : unit =
@ -1772,6 +1865,7 @@ module Make(Plugin : PLUGIN)
iter_clauses_on_trail ~f:(fun c -> Clause.set_marked store c false);
Log.debugf 3 (fun k->k "(@[sat.gc.done :collected %d@])" n_collected);
reduce_var_db self; (* now collect redundant variables *)
()
(* Decide on a new literal, and enqueue it into the trail *)
@ -1940,7 +2034,8 @@ module Make(Plugin : PLUGIN)
let[@inline] proof st = st.proof
let[@inline] add_lit self ?default_pol lit =
ignore (make_atom_ self lit ?default_pol : atom)
let a = make_atom_ self lit ?default_pol in
Var.set_persistent self.store (Atom.var a) true
let[@inline] set_default_pol (self:t) (lit:lit) (pol:bool) : unit =
let a = make_atom_ self lit ~default_pol:pol in
Var.set_default_pol self.store (Atom.var a) pol