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ENHANCED: CLP(ℤ): Reduce redundant propagator invocations during all_distinct/1 filtering

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First, the current propagator is now logged and not re-triggered
during filtering. Second, and more significantly, all neq_num/2
constraints are scheduled and processed before more global constraints
are invoked. In this way, all the distilled information can be taken
into account by subsequently invoked global constraints.

These changes yield a 3-fold improvement in several Sudoku instances,
and a significant runtime reduction in social golfer instance 8-4-9.
This commit is contained in:
Markus Triska
2022-07-25 20:08:54 +02:00
committed by Mark Thom
parent 4422ffe39f
commit c7caf6b7a9
1 changed files with 47 additions and 28 deletions
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75
src/lib/clpz.pl
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@@ -123,6 +123,8 @@
:- use_module(library(si)).
:- use_module(library(freeze)).
:- use_module(library(arithmetic)).
:- use_module(library(debug)).
:- use_module(library(format)).
% :- use_module(library(types)).
@@ -2241,8 +2243,8 @@ all_distinct(Ls) :-
fd_must_be_list(Ls, all_distinct(Ls)-1),
maplist(fd_variable, Ls),
make_propagator(pdistinct(Ls), Prop),
distinct_attach(Ls, Prop, []),
trigger_once(Prop).
new_queue(Q0),
phrase((distinct_attach(Ls, Prop, []),trigger_prop(Prop),do_queue), [Q0], _).
%% nvalue(?N, +Vars).
%
@@ -4050,12 +4052,13 @@ trigger_props(fd_props(Gs,Bs,Os)) -->
trigger_props_([]) --> [].
trigger_props_([P|Ps]) --> trigger_prop(P), trigger_props_(Ps).
trigger_prop(_P) :- true. % TODO: What to do?
trigger_prop(P) :- trigger_once(P).
trigger_prop(Propagator) -->
{ propagator_state(Propagator, State) },
( { State == dead } -> []
; { get_attr(State, clpz_aux, queued) } -> []
; { bb_get('$clpz_current_propagator', C), C == State } -> []
; % passive
%{ format("triggering: ~w\n", [Propagator]) },
{ put_attr(State, clpz_aux, queued) },
@@ -4148,12 +4151,13 @@ no_reactivation(pgcc_single(_,_)).
%no_reactivation(scalar_product(_,_,_,_)).
activate_propagator(propagator(P,State)) -->
% { portray_clause(running(P)) },
( State == dead -> []
; { del_attr(State, clpz_aux) },
( { no_reactivation(P) } ->
%b_setval('$clpz_current_propagator', State), TODO
run_propagator(P, State)
%b_setval('$clpz_current_propagator', [])
{ bb_b_put('$clpz_current_propagator', State) },
run_propagator(P, State),
{ bb_b_put('$clpz_current_propagator', []) }
; run_propagator(P, State)
)
).
@@ -4199,7 +4203,8 @@ queue_get_arg_(Queue, Which, Element) :-
).
queue_enabled --> state(queue(_,_,_,Aux)), { \+ get_atts(Aux, +enabled(false)) }.
disable_queue --> state(queue(_,_,_,Aux)), { put_atts(Aux, +enabled(false)) }.
enable_queue --> state(queue(_,_,_,Aux)), { put_atts(Aux, +enabled(true)) }.
portray_propagator(propagator(P,_), F) :- functor(P, F, _).
@@ -4394,14 +4399,14 @@ run_propagator(pdifferent(Left,Right,X,_), MState) -->
run_propagator(pexclude(Left,Right,X), MState).
run_propagator(pexclude(Left,Right,X), _) -->
{ ( ground(X) ->
disable_queue,
exclude_fire(Left, Right, X),
enable_queue
; true
) }.
( ground(X) ->
disable_queue,
exclude_fire(Left, Right, X),
enable_queue
; true
).
run_propagator(pdistinct(Ls), _MState) --> { distinct(Ls) }.
run_propagator(pdistinct(Ls), _MState) --> distinct(Ls).
run_propagator(pnvalue(N, Vars), _MState) --> { propagate_nvalue(N, Vars) }.
@@ -4435,8 +4440,8 @@ run_propagator(pgcc(Vs, _, Pairs), _) --> { gcc_global(Vs, Pairs) }.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
run_propagator(pcircuit(Vs), _MState) -->
{ distinct(Vs),
propagate_circuit(Vs) }.
distinct(Vs),
{ propagate_circuit(Vs) }.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -5933,12 +5938,12 @@ max_factor(L1, U1, L2, U2, Max) :-
CSPs", AAAI-94, Seattle, WA, USA, pp 362--367, 1994
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
distinct_attach([], _, _).
distinct_attach([X|Xs], Prop, Right) :-
distinct_attach([], _, _) --> [].
distinct_attach([X|Xs], Prop, Right) -->
( var(X) ->
init_propagator(X, Prop),
make_propagator(pexclude(Xs,Right,X), P1),
init_propagator(X, P1),
{ init_propagator(X, Prop),
make_propagator(pexclude(Xs,Right,X), P1),
init_propagator(X, P1) },
trigger_prop(P1)
; exclude_fire(Xs, Right, X)
),
@@ -6158,8 +6163,8 @@ with_local_attributes(Vars, Goal, Result) :-
local_attributes(Result,Vars),
true).
distinct(Vars) :-
with_local_attributes(Vars,
distinct(Vars) -->
{ with_local_attributes(Vars,
( difference_arcs(Vars, FreeLeft, FreeRight0),
length(FreeLeft, LFL),
length(FreeRight0, LFR),
@@ -6170,11 +6175,16 @@ distinct(Vars) :-
maplist(g_g0, FreeLeft),
scc(FreeLeft, g0_successors),
maplist(dfs_used, FreeRight),
phrase(distinct_goals(FreeLeft), Gs)), Gs),
phrase(distinct_goals(FreeLeft), Gs)), Gs) },
disable_queue,
maplist(call, Gs),
neq_nums(Gs),
enable_queue.
neq_nums([]) --> [].
neq_nums([neq_num(V,N)|VNs]) -->
% { portray_clause(neq_num(V, N)) },
neq_num(V, N), neq_nums(VNs).
distinct_goals([]) --> [].
distinct_goals([V|Vs]) -->
{ get_attr(V, edges, Es) },
@@ -6189,7 +6199,7 @@ distinct_goals_([flow_to(F,To)|Es], V) -->
get_attr(To, lowlink, L2),
L1 =\= L2 } ->
{ get_attr(To, value, N) },
[clpz:neq_num(V, N)]
[neq_num(V, N)]
; []
),
distinct_goals_(Es, V).
@@ -6381,6 +6391,10 @@ exclude_fire(Left, Right, E) :-
all_neq(Left, E),
all_neq(Right, E).
exclude_fire(Left, Right, E) -->
all_neq(Left, E),
all_neq(Right, E).
list_contains([X|Xs], Y) :-
( X == Y -> true
; list_contains(Xs, Y)
@@ -6942,6 +6956,11 @@ vs_key_min_others([V|Vs], Key, Min0, Min, Others) :-
)
).
all_neq([], _) --> [].
all_neq([X|Xs], C) -->
neq_num(X, C),
all_neq(Xs, C).
all_neq([], _).
all_neq([X|Xs], C) :-
neq_num(X, C),
@@ -6973,8 +6992,8 @@ circuit(Vs) :-
( L =:= 1 -> true
; neq_index(Vs, 1),
make_propagator(pcircuit(Vs), Prop),
distinct_attach(Vs, Prop, []),
trigger_once(Prop)
new_queue(Q0),
phrase((distinct_attach(Vs, Prop, []),trigger_prop(Prop),do_queue), [Q0], _)
).
neq_index([], _).