360 lines
10 KiB
Plaintext
360 lines
10 KiB
Plaintext
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%
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% each variable is represented by a node in a binary tree.
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% each node contains:
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% key,
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% current_value
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% Markov Blanket
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%
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:- module(gibbs, [gibbs/3,
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check_if_gibbs_done/1]).
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:- use_module(library(rbtrees),
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[new/1,
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insert/4]).
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:- use_module(library(lists),
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[member/2,
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append/3,
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delete/3]).
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:- use_module(library('clpbn/discrete_utils'), [
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project_from_CPT/3,
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reorder_CPT/5]).
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:- use_module(library('clpbn/utils'), [
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check_for_hidden_vars/3]).
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:- dynamic gibbs_params/3.
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gibbs([],_,_) :- !.
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gibbs(LVs,Vs0,_) :-
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check_for_hidden_vars(Vs0, Vs0, Vs1),
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sort(Vs1,Vs),
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(clpbn:output(xbif(XBifStream)) -> clpbn2xbif(XBifStream,vel,Vs) ; true),
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(clpbn:output(gviz(XBifStream)) -> clpbn2gviz(XBifStream,vel,Vs,LVs) ; true),
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initialise(Vs, Graph, LVs, OutputVars),
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% write(Graph),nl,
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process(Graph, OutputVars, Estimates),
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write(Estimates),nl,
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clean_up.
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initialise(LVs, Graph, GVs, OutputVars) :-
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init_keys(Keys0),
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gen_keys(LVs, 0, VLen, Keys0, Keys),
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functor(Graph,graph,VLen),
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graph_representation(LVs, Graph, 0, Keys),
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compile_graph(Graph),
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listing(mblanket),
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add_output_vars(GVs, Keys, OutputVars).
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init_keys(Keys0) :-
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new(Keys0).
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gen_keys([], I, I, Keys, Keys).
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gen_keys([V|Vs], I0, If, Keys0, Keys) :-
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clpbn:get_atts(V,[evidence(_)]), !,
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gen_keys(Vs, I0, If, Keys0, Keys).
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gen_keys([V|Vs], I0, If, Keys0, Keys) :-
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I is I0+1,
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insert(Keys0,V,I,KeysI),
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gen_keys(Vs, I, If, KeysI, Keys).
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graph_representation([],_,_,_).
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graph_representation([V|Vs], Graph, I0, Keys) :-
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clpbn:get_atts(V,[evidence(_)]), !,
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clpbn:get_atts(V, [dist(Vals,Table,Parents)]),
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get_sizes(Parents, Szs),
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length(Vals,Sz),
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project_evidence_out([V|Parents],[V|Parents],Table,[Sz|Szs],Variables,NewTable),
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% all variables are parents
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propagate2parents(Variables, NewTable, Variables, Graph, Keys),
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graph_representation(Vs, Graph, I0, Keys).
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graph_representation([V|Vs], Graph, I0, Keys) :-
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I is I0+1,
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clpbn:get_atts(V, [dist(Vals,Table,Parents)]),
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get_sizes(Parents, Szs),
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length(Vals,Sz),
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project_evidence_out([V|Parents],[V|Parents],Table,[Sz|Szs],Variables,NewTable),
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Variables = [V|NewParents],
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compact_table(NewTable, RepTable),
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add2graph(V, Vals, RepTable, NewParents, Graph, Keys),
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propagate2parents(NewParents, NewTable, Variables, Graph, Keys),
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graph_representation(Vs, Graph, I, Keys).
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get_sizes([], []).
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get_sizes([V|Parents], [Sz|Szs]) :-
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clpbn:get_atts(V, [dist(Vals,_,_)]),
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length(Vals,Sz),
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get_sizes(Parents, Szs).
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%
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% first, remove nodes that have evidence from tables.
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%
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project_evidence_out([],Deps,Table,_,Deps,Table).
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project_evidence_out([V|Parents],Deps,Table,Szs,NewDeps,NewTable) :-
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clpbn:get_atts(V,[evidence(_)]), !,
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NTab =.. [t|Table],
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project_from_CPT(V,tab(NTab,Deps,Szs),tab(ITable,IDeps,ISzs)),
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ITable =.. [_|LITable],
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project_evidence_out(Parents,IDeps,LITable,ISzs,NewDeps,NewTable).
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project_evidence_out([Par|Parents],Deps,Table,Szs,NewDeps,NewTable) :-
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project_evidence_out(Parents,Deps,Table,Szs,NewDeps,NewTable).
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propagate2parents([], _, _, _, _).
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propagate2parents([V|NewParents], Table, Variables, Graph, Keys) :-
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delete(Variables,V,NVs),
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reorder_CPT(Variables,Table,[V|NVs],NewTable,_),
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add2graph(V, _, NewTable, NVs, Graph, Keys),
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NewTable =.. [_|LNewTable],
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propagate2parents(NewParents, LNewTable, Variables, Graph, Keys).
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add2graph(V, Vals, Table, Parents, Graph, Keys) :-
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lookup(V, Index, Keys),
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(var(Vals) -> true ; length(Vals,Sz)),
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arg(Index, Graph, var(V,Index,_,Vals,Sz,VarSlot,_)),
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vars2indices(Parents,Keys,IParents),
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member(tabular(Table,Index,IParents), VarSlot), !.
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vars2indices([],_,[]).
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vars2indices([V|Parents],Keys,[I|IParents]) :-
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lookup(V, I, Keys),
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vars2indices(Parents,Keys,IParents).
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compact_table(NewTable, RepTable) :-
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NewTable = [_|_], !,
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RepTable =.. [t|NewTable].
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%
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% This is the really cool bit.
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%
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compile_graph(Graph) :-
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Graph =.. [_|VarsInfo],
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compile_vars(VarsInfo,Graph).
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compile_vars([],_).
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compile_vars([var(_,I,_,Vals,Sz,VarSlot,Parents)|VarsInfo],Graph) :-
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compile_var(I,Vals,Sz,VarSlot,Parents,Graph),
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compile_vars(VarsInfo,Graph).
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compile_var(I,Vals,Sz,VarSlot,Parents,Graph) :-
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fetch_all_parents(VarSlot,Graph,[],Parents,[],Sizes),
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mult_list(Sizes,1,TotSize),
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compile_var(TotSize,I,Vals,Sz,VarSlot,Parents,Sizes,Graph).
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fetch_all_parents([],_,Parents,Parents,Sizes,Sizes).
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fetch_all_parents([tabular(_,_,Ps)|CPTs],Graph,Parents0,ParentsF,Sizes0,SizesF) :-
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merge_this_parents(Ps,Graph,Parents0,ParentsI,Sizes0,SizesI),
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fetch_all_parents(CPTs,Graph,ParentsI,ParentsF,SizesI,SizesF).
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merge_this_parents([],_,Parents,Parents,Sizes,Sizes).
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merge_this_parents([I|Ps],Graph,Parents0,ParentsF,Sizes0,SizesF) :-
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member(I,Parents0), !,
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merge_this_parents(Ps,Graph,Parents0,ParentsF,Sizes0,SizesF).
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merge_this_parents([I|Ps],Graph,Parents0,ParentsF,Sizes0,SizesF) :-
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arg(I,Graph,var(_,I,_,Vals,_,_,_)),
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length(Vals, Sz),
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merge_this_parents(Ps,Graph,[I|Parents0],ParentsF,[Sz|Sizes0],SizesF).
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mult_list([],Mult,Mult).
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mult_list([Sz|Sizes],Mult0,Mult) :-
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MultI is Sz*Mult0,
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mult_list(Sizes,MultI,Mult).
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% we'd need 32 facts for each case
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compile_var(_TotSize,I,_Vals,Sz,CPTs,Parents,_Sizes,Graph) :-
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% TotSize =< 32,
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multiply_all(I,Parents,CPTs,Sz,Graph).
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multiply_all(I,Parents,CPTs,Sz,Graph) :-
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markov_blanket_instance(Parents,Graph,Values),
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multiply_all(CPTs,Sz,Graph,Probs),
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write(Values:Probs:CPTs),nl,
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store_mblanket(I,Values,Probs),
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fail.
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multiply_all(_,_,_,_,_).
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% note: what matters is how this predicate instantiates the temp
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% slot in the graph!
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markov_blanket_instance([],_,[]).
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markov_blanket_instance([I|Parents],Graph,[Pos|Values]) :-
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arg(I,Graph,var(_,I,Pos,Vals,_,_,_)),
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fetch_val(Vals,0,Pos),
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markov_blanket_instance(Parents,Graph,Values).
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% backtrack through every value in domain
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%
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fetch_val([_|_],Pos,Pos).
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fetch_val([_|Vals],I0,Pos) :-
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I is I0+1,
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fetch_val(Vals,I,Pos).
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multiply_all(CPTs,Size,Graph,Probs) :-
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init_factors(Size,Factors0),
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mult_factors(CPTs,Size,Graph,Factors0,Factors),
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normalise_factors(Factors,0,_,Probs,_).
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init_factors(0,[]) :- !.
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init_factors(I0,[1|Factors]) :-
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I is I0-1,
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init_factors(I,Factors).
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mult_factors([],_,_,Factors,Factors) :- !.
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mult_factors([tabular(Table,_,Parents)|CPTs],Size,Graph,Factors0,Factors) :-
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factor(Parents,Table,Graph,0,1,Indx0),
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functor(Table,_,CPTSize),
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Off is CPTSize//Size,
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Indx is Indx0+1,
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mult_with_probs(Factors0,Indx,Off,Table,FactorsI),
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mult_factors(CPTs,Size,Graph,FactorsI,Factors).
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factor([],_,_,Arg,_,Arg).
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factor([I|Parents],Table,Graph,Pos0,Weight0,Pos) :-
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arg(I,Graph,var(_,I,CurPos,_,Sz,_,_)),
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PosI is Pos0+(Weight0*CurPos),
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NWeight is Weight0*Sz,
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factor(Parents,Table,Graph,PosI,NWeight,Pos).
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mult_with_probs([],_,_,_,[]).
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mult_with_probs([F0|Factors0],Indx,Off,Table,[F|Factors]) :-
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arg(Indx,Table,P1),
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F is F0*P1,
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Indx1 is Indx+Off,
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mult_with_probs(Factors0,Indx1,Off,Table,Factors).
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normalise_factors([],Sum,Sum,[],1.0) :- Sum > 0.0.
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normalise_factors([F|Factors],S0,S,[P0|Probs],PF) :-
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Si is S0+F,
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normalise_factors(Factors,Si,S,Probs,P0),
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PF is P0-F/S.
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store_mblanket(I,Values,Probs) :-
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append(Values,Probs,Args),
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Rule =.. [mblanket,I|Args],
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assert(Rule).
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add_output_vars([], _, []).
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add_output_vars([V|LVs], Keys, [I|OutputVars]) :-
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lookup(V, I, Keys),
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add_output_vars(LVs, Keys, OutputVars).
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process(Graph,OutputVars,Estimates) :-
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gibbs_params(NChains,BurnIn,NSamples),
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functor(Graph,_,Len),
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init_chains(NChains,Len,Graph,Chains0),
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init_estimates(NChains,OutputVars,Graph,Est0),
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process_chains(BurnIn,BurnedIn,Chains0,Graph,Len,Est0,_),
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process_chains(NSamples,_,BurnedIn,Graph,Len,Est0,Estimates).
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%
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% I use an uniform distribution to generate the initial sample.
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%
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init_chains(0,_,_,[]) :- !.
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init_chains(I,Len,Graph,[Chain|Chains]) :-
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init_chain(Len,Graph,Chain),
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I1 is I-1,
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init_chains(I1,Len,Graph,Chains).
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init_chain(Len,Graph,Chain) :-
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gen_sample(Len,Graph,LChain),
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Chain =.. [sample|LChain].
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gen_sample(0,_,[]) :- !.
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gen_sample(I,Graph,[R|LChain]) :-
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arg(I,Graph,var(_,I,_,_,Sz,_,_)),
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R is integer(random*Sz),
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I1 is I-1,
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gen_sample(I1,Graph,LChain).
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init_estimates(0,_,_,[]) :- !.
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init_estimates(NChains,OutputVars,Graph,[Est|Est0]) :-
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NChainsI is NChains-1,
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init_estimate(OutputVars,Graph,Est),
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init_estimates(NChainsI,OutputVars,Graph,Est0).
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init_estimate([],_,[]).
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init_estimate([V|OutputVars],Graph,[[I|E0L]|Est]) :-
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arg(V,Graph,var(_,I,_,_,Sz,_,_)),
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gen_e0(Sz,E0L),
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init_estimate(OutputVars,Graph,Est).
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gen_e0(0,[]) :- !.
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gen_e0(Sz,[0|E0L]) :-
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Sz1 is Sz-1,
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gen_e0(Sz1,E0L).
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process_chains(0,F,F,_,_,Est,Est) :- !.
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process_chains(ToDo,End,Start,Graph,Len,Est0,Estf) :-
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process_chains(Start,Int,Graph,Len,Est0,Esti),
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ToDo1 is ToDo-1,
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process_chains(ToDo1,End,Int,Graph,Len,Esti,Estf).
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process_chains([], [], _, _,[],[]).
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process_chains([Sample0|Samples0], [Sample|Samples], Graph, SampLen,[E0|E0s],[Ef|Efs]) :-
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functor(Sample,sample,SampLen),
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do_sample(0,SampLen,Sample,Sample0,Graph),
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update_estimate(E0,Sample,Ef),
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process_chains(Samples0, Samples, Graph, SampLen,E0s,Efs).
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do_sample(Len,Len,_,_,_) :- !.
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do_sample(I0,Len,Sample,Sample0,Graph) :-
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I is I0+1,
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do_var(I,Sample,Sample0,Graph),
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do_sample(I,Len,Sample,Sample0,Graph).
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do_var(I,Sample,Sample0,Graph) :-
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arg(I,Graph,var(_,I,_,_,Sz,_,Parents)),
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length(Vals,Sz),
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fetch_parents(Parents,I,Sample,Sample0,Args,Vals),
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Goal =.. [mblanket,I|Args],
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(call(Goal) -> true ; throw(agg)),
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X is random,
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pick_new_value(Vals,X,0,Val),
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arg(I,Sample,Val).
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fetch_parents([],_,_,_,Args,Args).
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fetch_parents([P|Parents],I,Sample,Sample0,[VP|Args],Vals) :-
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P < I, !,
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arg(P,Sample,VP),
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fetch_parents(Parents,I,Sample,Sample0,Args,Vals).
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fetch_parents([P|Parents],I,Sample,Sample0,[VP|Args],Vals) :-
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|
|
arg(P,Sample0,VP),
|
||
|
|
fetch_parents(Parents,I,Sample,Sample0,Args,Vals).
|
||
|
|
|
||
|
|
pick_new_value([V|_],X,Val,Val) :-
|
||
|
|
X < V, !.
|
||
|
|
pick_new_value([_|Vals],X,I0,Val) :-
|
||
|
|
I is I0+1,
|
||
|
|
pick_new_value(Vals,X,I,Val).
|
||
|
|
|
||
|
|
update_estimate([],_,[]).
|
||
|
|
update_estimate([[I|E]|E0],Sample,[[I|NE]|Ef]) :-
|
||
|
|
arg(I,Sample,V),
|
||
|
|
update_estimate_for_var(V,E,NE),
|
||
|
|
update_estimate(E0,Sample,Ef).
|
||
|
|
|
||
|
|
update_estimate_for_var(0,[X|T],[X1|T]) :- !, X1 is X+1.
|
||
|
|
update_estimate_for_var(V,[E|Es],[E|NEs]) :-
|
||
|
|
V1 is V-1,
|
||
|
|
update_estimate_for_var(V1,Es,NEs).
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
check_if_gibbs_done(Var) :-
|
||
|
|
get_atts(Var, [dist(_)]), !.
|
||
|
|
|
||
|
|
clean_up :-
|
||
|
|
current_predicate(mblanket,P),
|
||
|
|
retractall(P),
|
||
|
|
fail.
|
||
|
|
clean_up.
|
||
|
|
|
||
|
|
|
||
|
|
gibbs_params(5,1000,100000).
|
||
|
|
|