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yap-6.3/CLPBN/clpbn/vel.yap
vsc ab1cd9bb60 introduce CLPBN in system 
git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1094 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
2004-07-15 16:23:44 +00:00

496 lines
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Prolog
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/***********************************
Variable Elimination in Prolog
How to do it
Three steps:
build the graph:
- for all variables, find out
all tables they connect to;
multiply their size
order by size
*********************************/
:- module(vel, [vel/3,
check_if_vel_done/1]).
:- attribute size/1, posterior/4, all_diffs/1.
:- use_module(library(ordsets), [ord_union/3
]).
:- use_module(library(lists),
[
append/3,
member/2
]).
check_if_vel_done(Var) :-
get_atts(Var, [size(_)]), !.
vel(LVs,Vs0,AllDiffs) :-
check_for_hidden_vars(Vs0, Vs0, Vs1),
sort(Vs1,Vs),
find_all_clpbn_vars(Vs, LV0, Tables0),
find_all_table_deps(Tables0, LV0),
process(LV0, LVs, tab(Dist,_,_)),
Dist =.. [_|Ps0],
normalise(Ps0,Ps),
bind_vals(LVs,Ps,AllDiffs).
%
% It may happen that variables from a previous query may still be around.
% and be used in the next evaluation, so we cannot trust the list of *new*
% variables.
%
check_for_hidden_vars([], _, []).
check_for_hidden_vars([V|Vs], AllVs0, [V|NVs]) :-
check_for_extra_variables(V,AllVs0, AllVs, Vs, IVs),
check_for_hidden_vars(IVs, AllVs, NVs).
check_for_extra_variables(V,AllVs0, AllVs, Vs, IVs) :-
clpbn:get_atts(V, [dist(([_|_].[V1|LV])=>_)]), !,
add_old_variables([V1|LV], AllVs0, AllVs, Vs, IVs).
check_for_extra_variables(_,AllVs, AllVs, Vs, Vs).
add_old_variables([], AllVs, AllVs, Vs, Vs).
add_old_variables([V1|LV], AllVs0, AllVs, Vs, IVs) :-
not_var_member(AllVs0, V1), !,
add_old_variables(LV, [V1|AllVs0], AllVs, [V1|Vs], IVs).
add_old_variables([_|LV], AllVs0, AllVs, Vs, IVs) :-
add_old_variables(LV, AllVs0, AllVs, Vs, IVs).
find_all_clpbn_vars([], [], []) :- !.
find_all_clpbn_vars([V|Vs], [var(V,I,Sz,Vals,_,_)|LV], [table(I,Table,Deps,Sizes)|Tables]) :-
var_with_deps(V, Table, Deps, Sizes, Vals), !,
get_dist_els(V,Sz),
find_all_clpbn_vars(Vs, LV, Tables).
var_with_deps(V, Table, Deps, Sizes, Vals) :-
clpbn:get_atts(V, [dist(D=>Vals)]),
from_dist_get(D,Vals,OTable,VDeps),
reorder_table([V|VDeps],Sizes,OTable,Deps,Table).
from_dist_get(average.Vs0,Vals,Lf,Vs) :- !,
handle_average(Vs0,Vals,Lf,Vs).
from_dist_get(sum.Vs0,Vals,Lf,Vs) :- !,
handle_sum(Vs0, Vals, Lf, Vs).
from_dist_get(normalised_average(Max).Vs0,Vals,Lf,Vs) :- !,
handle_normalised_average(Max,Vs0,Vals,Lf,Vs).
from_dist_get(([A|B].[C|D]),_,[A|B],[C|D]) :- !.
from_dist_get([A|B],_,[A|B],[]).
handle_average(Vs0,Vals,Lf,Vs) :-
sort(Vs0,Vs),
generate_indices(Vals,Inds,0,Av),
combine_all(Vs, Inds, Cs),
length(Vs, Max),
average_possible_cases(0,Av,Max,Cs,Lf).
handle_sum(Vs0, Vals, Lf, Vs) :-
sort(Vs0,Vs),
length(Vals,Sz),
combine_all(Vs, Cs),
sum_possible_cases(0,Sz,Cs,Lf).
handle_normalised_average(Max,Vs0,Vals,Lf,Vs) :-
sort(Vs0,Vs),
generate_indices(Vals,_,0,Sz),
combine_all(Vs, Cs),
average_possible_cases(0,Sz,Max,Cs,Lf).
generate_indices([],[],Av,Av).
generate_indices([_|Ls],[I|Inds],I,Av) :-
I1 is I+1,
generate_indices(Ls,Inds,I1,Av).
combine_all([], [[]]).
combine_all([V|LV], Cs) :-
combine_all(LV, Cs0),
get_dist_els(V,Sz),
generate_indices(0, Sz, Vals),
add_vals(Vals, Cs0, Cs).
combine_all([], _, [[]]).
combine_all([_|LV], Vals, Cs) :-
combine_all(LV, Vals, Cs0),
add_vals(Vals, Cs0, Cs).
generate_indices(Sz,Sz,[]) :- !.
generate_indices(I0,Sz,[I0|Vals]) :-
I is I0+1,
generate_indices(I,Sz,Vals).
add_vals([], _, []).
add_vals([V|Vs], Cs0, Csf) :-
add_vals(Vs, Cs0, Cs),
add_val_to_cases(Cs0, V, Cs, Csf).
add_val_to_cases([], _, Cs, Cs).
add_val_to_cases([C|Cs], V, Cs0, [[V|C]|Csf]) :-
add_val_to_cases(Cs, V, Cs0, Csf).
sum_all([],N,N).
sum_all([C|Cs],N0,N) :-
X is C+N0,
sum_all(Cs,X,N).
average_possible_cases(Av,Av,_,_,[]) :- !.
average_possible_cases(I,Av,Max,Cs,Lf) :-
average_cases2(Cs,I,Max,Lf,L0),
I1 is I+1,
average_possible_cases(I1,Av,Max,Cs,L0).
average_cases2([], _, _, L, L).
average_cases2([C|Cs], I, Av, [P|Lf], L0) :-
calculate_avg_prob(C, I, Av, P),
average_cases2(Cs, I, Av, Lf, L0).
calculate_avg_prob(C, I, Av, 1.0) :-
sum_all(C,0,N),
I =:= integer(round(N/Av)), !.
calculate_avg_prob(_, _, _, 0.0).
sum_possible_cases(Av,Av,_,[]) :- !.
sum_possible_cases(I,Av,Cs,Lf) :-
sum_cases2(Cs,I,Lf,L0),
I1 is I+1,
sum_possible_cases(I1,Av,Cs,L0).
sum_cases2([], _, L, L).
sum_cases2([C|Cs], I, [P|Lf], L0) :-
calculate_sum_prob(C, I, P),
sum_cases2(Cs, I, Lf, L0).
calculate_sum_prob(C, I, 1.0) :-
sum_all(C,0,N),
I =:= N, !.
calculate_sum_prob(_, _, 0.0).
get_sizes([], []).
get_sizes([V|Deps], [Sz|Sizes]) :-
get_dist_els(V,Sz),
get_sizes(Deps, Sizes).
get_dist_els(V,Sz) :-
get_atts(V, [size(Sz)]), !.
get_dist_els(V,Sz) :-
clpbn:get_atts(V, [dist(_=>Vals)]), !,
length(Vals,Sz),
put_atts(V, [size(Sz)]).
reorder_table(Vs0, Sizes, T0, Vs, TF) :-
get_sizes(Vs0, Szs),
numb_vars(Vs0, Szs, _, VPs0, VLs0),
keysort(VLs0, VLs),
compute_new_factors(VLs, _, Vs, Sizes),
get_factors(VLs0,Fs),
length(T0,L),
functor(TF,t,L),
copy_to_new_array(T0, 0, VPs0, Fs, TF).
numb_vars([], [], 1, [], []).
numb_vars([V|Vs], [L|Ls], A0, [Ai|VPs], [V-(L,_)|VLs]) :-
numb_vars(Vs, Ls, Ai, VPs, VLs),
A0 is Ai*L.
compute_new_factors([], 1, [], []).
compute_new_factors([V-(L,F)|VLs], NF, [V|Vs], [L|Szs]) :-
compute_new_factors(VLs, F, Vs, Szs),
NF is F*L.
get_factors([],[]).
get_factors([_-(_,F)|VLs0],[F|Fs]) :-
get_factors(VLs0,Fs).
copy_to_new_array([], _, _, _, _).
copy_to_new_array([P|Ps], I, F0s, Fs, S) :-
convert_factor(F0s, Fs, I, N),
I1 is I+1,
N1 is N+1,
arg(N1,S,P),
copy_to_new_array(Ps, I1, F0s, Fs, S).
convert_factor([], [], _, 0).
convert_factor([F0|F0s], [F|Fs], I, OUT) :-
X is I//F0,
NI is I mod F0,
NEXT is F*X,
convert_factor(F0s, Fs, NI, OUT1),
OUT is OUT1+NEXT.
find_all_table_deps(Tables0, LV) :-
find_dep_graph(Tables0, DepGraph0),
sort(DepGraph0, DepGraph),
add_table_deps_to_variables(LV, DepGraph).
find_dep_graph([], []).
find_dep_graph([table(I,Tab,Deps,Sizes)|Tables], DepGraph) :-
add_table_deps(Deps, I, Deps, Tab, Sizes, DepGraph0, DepGraph),
find_dep_graph(Tables, DepGraph0).
add_table_deps([], _, _, _, _, DepGraph, DepGraph).
add_table_deps([V|Deps], I, Deps0, Table, Sizes, DepGraph0, [V-tab(Table,Deps0,Sizes)|DepGraph]) :-
add_table_deps(Deps, I, Deps0, Table, Sizes, DepGraph0, DepGraph).
add_table_deps_to_variables([], []).
add_table_deps_to_variables([var(V,_,_,_,Deps,K)|LV], DepGraph) :-
steal_deps_for_variable(DepGraph, V, NDepGraph, Deps),
compute_size(Deps,[],K),
add_table_deps_to_variables(LV, NDepGraph).
steal_deps_for_variable([V-Info|DepGraph], V0, NDepGraph, [Info|Deps]) :-
V == V0, !,
steal_deps_for_variable(DepGraph, V0, NDepGraph, Deps).
steal_deps_for_variable(DepGraph, _, DepGraph, []).
compute_size([],Vs,K) :-
% use sizes now
length(Vs,K).
% multiply_sizes(Vs,1,K).
compute_size([tab(_,Vs,_)|Tabs],Vs0,K) :-
ord_union(Vs,Vs0,VsI),
compute_size(Tabs,VsI,K).
multiply_sizes([],K,K).
multiply_sizes([V|Vs],K0,K) :-
get_dist_els(V, Sz),
KI is K0*Sz,
multiply_sizes(Vs,KI,K).
process(LV0, InputVs, Out) :-
find_best(LV0, V0, 10000, V, WorkTables, LVI, InputVs),
V \== V0, !,
multiply_tables(WorkTables, Table),
propagate_evidence(V, Evs),
project(V,Table,NewTable,Evs),
include(LVI,NewTable,V,LV2),
process(LV2, InputVs, Out).
process(LV0, _, Out) :-
fetch_tables(LV0, WorkTables),
multiply_tables(WorkTables, Out).
find_best([], V, _, V, _, [], _).
find_best([var(V,I,Sz,Vals,Deps,K)|LV], _, Threshold, VF, NWorktables, LVF, Inputs) :-
K < Threshold,
not_var_member(Inputs, V), !,
find_best(LV, V, K, VF, WorkTables,LV0, Inputs),
(V == VF ->
LVF = LV0, Deps = NWorktables
;
LVF = [var(V,I,Sz,Vals,Deps,K)|LV0], WorkTables = NWorktables
).
find_best([V|LV], V0, Threshold, VF, WorkTables, [V|LVF], Inputs) :-
find_best(LV, V0, Threshold, VF, WorkTables, LVF, Inputs).
multiply_tables([Table], Table) :- !.
multiply_tables([tab(Tab1,Deps1,Szs1), tab(Tab2,Deps2,Sz2)| Tables], Out) :-
multiply_table(Tab1, Deps1, Szs1, Tab2, Deps2, Sz2, NTab, NDeps, NSz),
multiply_tables([tab(NTab,NDeps,NSz)| Tables], Out).
propagate_evidence(V, Evs) :-
clpbn:get_atts(V, [evidence(Ev),dist(_=>Out)]), !,
generate_szs_with_evidence(Out,Ev,Evs).
propagate_evidence(_, _).
generate_szs_with_evidence([],_,[]).
generate_szs_with_evidence([Ev|Out],Ev,[ok|Evs]) :- !,
generate_szs_with_evidence(Out,Ev,Evs).
generate_szs_with_evidence([_|Out],Ev,[not_ok|Evs]) :-
generate_szs_with_evidence(Out,Ev,Evs).
fetch_tables([], []).
fetch_tables([var(_,_,_,_,Deps,_)|LV0], Tables) :-
append(Deps,Tables0,Tables),
fetch_tables(LV0, Tables0).
not_var_member([], _).
not_var_member([V1|Vs], V) :- V1 \== V,
not_var_member(Vs, V).
multiply_table(Tab1, Deps1, Szs1, Tab2, Deps2, Szs2, NTab, NDeps, NSzs) :-
deps_union(Deps1,Szs1,Fs10,Deps2,Szs2,Fs20,NDeps,NSzs),
factors(NSzs, Fs, Total),
factors(Fs10, Fs1, _),
factors(Fs20, Fs2, _),
elements(0, Total, Fs, Fs1, Fs2, Tab1, Tab2, LTab),
NTab =.. [t|LTab].
deps_union([],[],[],[],[],[],[],[]) :- !.
deps_union([],[],Fs1,[V2|Deps2],[Sz|Szs2],[Sz|Szs2],[V2|Deps2],[Sz|Szs2]) :- !,
mk_zeros([Sz|Szs2],Fs1).
deps_union([V1|Deps1],[Sz|Szs1],[Sz|Szs1],[],[],Fs2,[V1|Deps1],[Sz|Szs1]) :- !,
mk_zeros([Sz|Szs1],Fs2).
deps_union([V1|Deps1],[Sz|Szs1],[Sz|Fs1],[V2|Deps2],[Sz|Szs2],[Sz|Fs2],[V1|NDeps],[Sz|NSzs]) :- V1 == V2, !,
deps_union(Deps1,Szs1,Fs1,Deps2,Szs2,Fs2,NDeps,NSzs).
deps_union([V1|Deps1],[Sz1|Szs1],[Sz1|Fs1],[V2|Deps2],Szs2,[0|Fs2],[V1|NDeps],[Sz1|NSzs]) :- V1 @< V2, !,
deps_union(Deps1,Szs1,Fs1,[V2|Deps2],Szs2,Fs2,NDeps,NSzs).
deps_union([V1|Deps1],Szs1,[0|Fs1],[V2|Deps2],[Sz|Szs2],[Sz|Fs2],[V2|NDeps],[Sz|NSzs]) :-
deps_union([V1|Deps1],Szs1,Fs1,Deps2,Szs2,Fs2,NDeps,NSzs).
mk_zeros([],[]).
mk_zeros([_|Szs],[0|Fs]) :-
mk_zeros(Szs,Fs).
factors([], [], 1).
factors([0|Ls], [0|NLs], Prod) :- !,
factors(Ls, NLs, Prod).
factors([N|Ls], [Prod0|NLs], Prod) :-
factors(Ls, NLs, Prod0),
Prod is Prod0*N.
elements(Total, Total, _, _, _, _, _, []) :- !.
elements(I, Total, Fs, Fs1, Fs2, Tab1, Tab2, [El|Els]) :-
element(Fs, I, 1, Fs1, 1, Fs2, Tab1, Tab2, El),
I1 is I+1,
elements(I1, Total, Fs, Fs1, Fs2, Tab1, Tab2, Els).
element([], _, P1, [], P2, [], Tab1, Tab2, El) :-
arg(P1, Tab1, El1),
arg(P2, Tab2, El2),
El is El1*El2.
element([F|Fs], I, P1, [F1|Fs1], P2, [F2|Fs2], Tab1, Tab2, El) :-
FF is I // F,
NP1 is P1+F1*FF,
NP2 is P2+F2*FF,
NI is I mod F,
element(Fs, NI, NP1, Fs1, NP2, Fs2, Tab1, Tab2, El).
%
project(V,tab(Table,Deps,Szs),tab(NewTable,NDeps,NSzs),Evs) :-
functor(Table,_,Max),
find_projection_factor(Deps, V, NDeps, Szs, NSzs, F, Sz),
OLoop is Max//(Sz*F),
project_outer_loop(0,OLoop,F,Sz,Table,Evs,NTabl),
NewTable =.. [t|NTabl].
find_projection_factor([V|Deps], V1, Deps, [Sz|Szs], Szs, F, Sz) :-
V == V1, !,
mult(Szs, 1, F).
find_projection_factor([V|Deps], V1, [V|NDeps], [Sz|Szs], [Sz|NSzs], F, NSz) :-
find_projection_factor(Deps, V1, NDeps, Szs, NSzs, F, NSz).
mult([], F, F).
mult([Sz|Szs], Sz0, F) :-
SzI is Sz0*Sz,
mult(Szs, SzI, F).
project_outer_loop(OLoop,OLoop,_,_,_,_,[]) :- !.
project_outer_loop(I,OLoop,F,Sz,Table,Evs,NTabl) :-
Base is I*Sz*F,
project_mid_loop(0,F,Base,Sz,Table,Evs,NTabl,NTabl0),
I1 is I+1,
project_outer_loop(I1,OLoop,F,Sz,Table,Evs,NTabl0).
project_mid_loop(F,F,_,_,_,_,NTabl,NTabl) :- !.
project_mid_loop(I,F,Base,Sz,Table,Evs,[Ent|NTablF],NTabl0) :-
I1 is I+1,
NBase is I+Base,
project_inner_loop(0,Sz,Evs,NBase,F,Table,0.0,Ent),
project_mid_loop(I1,F,Base,Sz,Table,Evs,NTablF,NTabl0).
project_inner_loop(Sz,Sz,[],_,_,_,Ent,Ent) :- !.
project_inner_loop(I,Sz,[ok|Evs],NBase,F,Table,Ent0,Ent) :- !,
I1 is I+1,
Pos is NBase+I*F+1,
arg(Pos,Table,E1),
Ent1 is E1+Ent0,
project_inner_loop(I1,Sz,Evs,NBase,F,Table,Ent1,Ent).
project_inner_loop(I,Sz,[_|Evs],NBase,F,Table,Ent0,Ent) :- !,
I1 is I+1,
project_inner_loop(I1,Sz,Evs,NBase,F,Table,Ent0,Ent).
include([],_,_,[]).
include([var(V,P,VSz,D,Tabs,Est)|LV],tab(T,Vs,Sz),V1,[var(V,P,VSz,D,Tabs,Est)|NLV]) :-
not_var_member(Vs,V), !,
include(LV,tab(T,Vs,Sz),V1,NLV).
include([var(V,P,VSz,D,Tabs,_)|LV],Table,NV,[var(V,P,VSz,D,NTabs,NEst)|NLV]) :-
update_tables(Tabs,NTabs,Table,NV,[],NEst),
include(LV,Table,NV,NLV).
update_tables([],[Table],Table,_,AVs,NS) :-
Table = tab(_,Vs,_),
ord_union(Vs,AVs,TVs),
length(TVs,NS).
update_tables([tab(Tab0,Vs,Sz)|Tabs],[tab(Tab0,Vs,Sz)|NTabs],Table,V,AVs0,NS) :-
not_var_member(Vs,V), !,
ord_union(Vs,AVs0,AVsI),
update_tables(Tabs,NTabs,Table,V,AVsI,NS).
update_tables([_|Tabs],NTabs,Table,V,AVs0,NS) :-
update_tables(Tabs,NTabs,Table,V,AVs0,NS).
bind_vals([],_,_) :- !.
% simple case, we want a distribution on a single variable.
%bind_vals([V],Ps) :- !,
% clpbn:get_atts(V, [dist(_=>Vals)]),
% put_atts(V, posterior([V], Vals, Ps)).
% complex case, we want a joint distribution, do it on a leader.
% should split on cliques ?
bind_vals(Vs,Ps,AllDiffs) :-
get_all_combs(Vs, Vals),
Vs = [V|_],
put_atts(V, posterior(Vs, Vals, Ps,AllDiffs)).
get_all_combs(Vs, Vals) :-
get_all_doms(Vs,Ds),
findall(L,ms(Ds,L),Vals).
get_all_doms([], []).
get_all_doms([V|Vs], [D|Ds]) :-
clpbn:get_atts(V, [dist(_=>D)]),
get_all_doms(Vs, Ds).
ms([], []).
ms([H|L], [El|Els]) :-
member(El,H),
ms(L, Els).
normalise(Ps0,Ps) :-
add_all(Ps0,0.0,Sum),
divide_by_sum(Ps0,Sum,Ps).
add_all([],Sum,Sum).
add_all([P|Ps0],Sum0,Sum) :-
SumI is Sum0+P,
add_all(Ps0,SumI,Sum).
divide_by_sum([],_,[]).
divide_by_sum([P|Ps0],Sum,[PN|Ps]) :-
PN is P/Sum,
divide_by_sum(Ps0,Sum,Ps).
attribute_goal(V, G) :-
get_atts(V, [posterior(Vs,Vals,Ps,AllDiffs)]),
massage_out(Vs, Vals, Ps, G, AllDiffs).
massage_out(Vs, [D], [P], p(CEqs)=P, AllDiffs) :- !,
gen_eqs(Vs,D,Eqs),
add_alldiffs(AllDiffs,Eqs,CEqs).
massage_out(Vs, [D|Ds], [P|Ps], (p(CEqs)=P,G) , AllDiffs) :-
gen_eqs(Vs,D,Eqs),
add_alldiffs(AllDiffs,Eqs,CEqs),
massage_out(Vs, Ds, Ps, G, AllDiffs).
gen_eqs([V], [D], (V=D)) :- !.
gen_eqs([V], D, (V=D)) :- !.
gen_eqs([V|Vs], [D|Ds], ((V=D),Eqs)) :-
gen_eqs(Vs,Ds,Eqs).
add_alldiffs([],Eqs,Eqs).
add_alldiffs(AllDiffs,Eqs,(Eqs/alldiff(AllDiffs))).
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