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yap-6.3/CLPBN/clpbn/vel.yap

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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('clpbn/xbif'), [clpbn2xbif/3]).
:- use_module(library('clpbn/graphviz'), [clpbn2gviz/4]).
:- use_module(library('clpbn/utils'), [
clpbn_not_var_member/2,
check_for_hidden_vars/3]).
:- use_module(library('clpbn/discrete_utils'), [
project_from_CPT/3,
reorder_CPT/5,
get_dist_size/2]).
:- use_module(library(lists),
[
append/3,
member/2
]).
check_if_vel_done(Var) :-
get_atts(Var, [size(_)]), !.
vel(LVs0,Vs0,AllDiffs) :-
sort(LVs0,LVs1),
get_rid_of_ev_vars(LVs1,LVs),
do_vel(LVs,Vs0,AllDiffs).
do_vel([],_,_) :- !.
do_vel(LVs,Vs0,AllDiffs) :-
check_for_hidden_vars(Vs0, Vs0, Vs1),
sort(Vs1,Vs),
find_all_clpbn_vars(Vs, LV0, LVi, Tables0),
find_all_table_deps(Tables0, LV0),
(clpbn:output(xbif(XBifStream)) -> clpbn2xbif(XBifStream,vel,Vs) ; true),
(clpbn:output(gviz(XBifStream)) -> clpbn2gviz(XBifStream,vel,Vs,LVs) ; true),
process(LVi, LVs, tab(Dist,_,_)),
Dist =.. [_|Ps0],
normalise(Ps0,Ps),
bind_vals(LVs,Ps,AllDiffs).
%
% some variables might already have evidence in the data-base.
%
get_rid_of_ev_vars([],[]).
get_rid_of_ev_vars([V|LVs0],LVs) :-
clpbn:get_atts(V, [evidence(Ev)]), !,
put_atts(V, [posterior([],Ev,[],[])]), !,
get_rid_of_ev_vars(LVs0,LVs).
get_rid_of_ev_vars([V|LVs0],[V|LVs]) :-
get_rid_of_ev_vars(LVs0,LVs).
find_all_clpbn_vars([], [], [], []) :- !.
find_all_clpbn_vars([V|Vs], [Var|LV], ProcessedVars, [table(I,Table,Parents,Sizes)|Tables]) :-
var_with_deps(V, Table, Parents, Sizes, Ev, Vals), !,
% variables with evidence should not be processed.
(var(Ev) ->
Var = var(V,I,Sz,Vals,Parents,Ev,_,_),
vel_get_dist_size(V,Sz),
ProcessedVars = [Var|ProcessedVars0]
;
ProcessedVars = ProcessedVars0
),
find_all_clpbn_vars(Vs, LV, ProcessedVars0, Tables).
var_with_deps(V, Table, Deps, Sizes, Ev, Vals) :-
clpbn:get_atts(V, [dist(Vals,OTable,Parents)]),
( clpbn:get_atts(V, [evidence(Ev)]) -> true ; true),
reorder_CPT([V|Parents],OTable,Deps0,Table0,Sizes0),
simplify_evidence(Deps0, Table0, Deps0, Sizes0, Table, Deps, Sizes).
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),
% ( clpbn:get_atts(V,[key(Key)]) -> format('~w:~w~n',[Key,K]) ; true),
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) :-
vel_get_dist_size(V, Sz),
KI is K0*Sz,
multiply_sizes(Vs,KI,K).
process(LV0, InputVs, Out) :-
find_best(LV0, V0, -1, V, WorkTables, LVI, InputVs),
V \== V0, !,
%format('1 ~w: ~w~n',[V,WorkTables]),
multiply_tables(WorkTables, tab(Tab0,Deps0,_)),
Tab0 =.. [_|LTab0],
reorder_CPT(Deps0,LTab0,Deps,Tab,Sizes),
Table = tab(Tab,Deps,Sizes),
%format('2 ~w: ~w~n',[V,Table]),
project_from_CPT(V,Table,NewTable),
%format('3 ~w: ~w~n',[V,NewTable]),
include(LVI,NewTable,V,LV2),
process(LV2, InputVs, Out).
process(LV0, _, Out) :-
fetch_tables(LV0, WorkTables),
multiply_tables(WorkTables, Out).
find_best([], V, _TF, V, _, [], _).
%:-
% clpbn:get_atts(V,[key(K)]), write(chosen:K:TF), nl.
% root_with_single_child
%find_best([var(V,I,_,_,[],Ev,[Dep],K)|LV], _, _, V, [Dep], LVF, Inputs) :- !.
find_best([var(V,I,Sz,Vals,Parents,Ev,Deps,K)|LV], _, Threshold, VF, NWorktables, LVF, Inputs) :-
( K < Threshold ; Threshold < 0),
clpbn_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,Parents,Ev,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).
simplify_evidence([], Table, Deps, Sizes, Table, Deps, Sizes).
simplify_evidence([V|VDeps], Table0, Deps0, Sizes0, Table, Deps, Sizes) :-
clpbn:get_atts(V, [evidence(_)]), !,
project_from_CPT(V,tab(Table0,Deps0,Sizes0),tab(NewTable,Deps1,Sizes1)),
simplify_evidence(VDeps, NewTable, Deps1, Sizes1, Table, Deps, Sizes).
simplify_evidence([_|VDeps], Table0, Deps0, Sizes0, Table, Deps, Sizes) :-
simplify_evidence(VDeps, Table0, Deps0, Sizes0, Table, Deps, Sizes).
fetch_tables([], []).
fetch_tables([var(_,_,_,_,_,_,Deps,_)|LV0], Tables) :-
append(Deps,Tables0,Tables),
fetch_tables(LV0, Tables0).
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).
%
include([],_,_,[]).
include([var(V,P,VSz,D,Parents,Ev,Tabs,Est)|LV],tab(T,Vs,Sz),V1,[var(V,P,VSz,D,Parents,Ev,Tabs,Est)|NLV]) :-
clpbn_not_var_member(Vs,V), !,
include(LV,tab(T,Vs,Sz),V1,NLV).
include([var(V,P,VSz,D,Parents,Ev,Tabs,_)|LV],Table,NV,[var(V,P,VSz,D,Parents,Ev,NTabs,NEst)|NLV]) :-
update_tables(Tabs,NTabs,Table,NV),
compute_size(NTabs, [], NEst),
include(LV,Table,NV,NLV).
update_tables([],[Table],Table,_).
update_tables([tab(Tab0,Vs,Sz)|Tabs],[tab(Tab0,Vs,Sz)|NTabs],Table,V) :-
clpbn_not_var_member(Vs,V), !,
update_tables(Tabs,NTabs,Table,V).
update_tables([_|Tabs],NTabs,Table,V) :-
update_tables(Tabs,NTabs,Table,V).
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).
%
% what is actually output
%
attribute_goal(V, G) :-
get_atts(V, [posterior(Vs,Vals,Ps,AllDiffs)]),
massage_out(Vs, Vals, Ps, G, AllDiffs, V).
massage_out([], Ev, _, V=Ev, _, V) :- !.
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, V) :-
gen_eqs(Vs,D,Eqs),
add_alldiffs(AllDiffs,Eqs,CEqs),
massage_out(Vs, Ds, Ps, G, AllDiffs, V).
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))).
vel_get_dist_size(V,Sz) :-
get_atts(V, [size(Sz)]), !.
vel_get_dist_size(V,Sz) :-
get_dist_size(V,Sz), !,
put_atts(V, [size(Sz)]).