122 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			Prolog
		
	
	
	
	
	
			
		
		
	
	
			122 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			Prolog
		
	
	
	
	
	
%
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% Learn parameters using the BNT toolkit
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%
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:- yap_flag(unknown,error).
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:- style_check(all).
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:- module(bnt_parameters, [learn_parameters/2]).
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:- use_module(library('clpbn'),
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		[clpbn_flag/3]).
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:- use_module(library('clpbn/bnt'),
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		[create_bnt_graph/2]).
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:- use_module(library('clpbn/display'),
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		[clpbn_bind_vals/3]).
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:- use_module(library('clpbn/dists'),
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		[get_dist_domain/2]).
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:- use_module(library(matlab),
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		[matlab_initialized_cells/4,
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		 matlab_call/2,
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		 matlab_get_variable/2
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		]).
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:- dynamic bnt_em_max_iter/1.
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bnt_em_max_iter(10).
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% syntactic sugar for matlab_call.
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:- op(800,yfx,<--).
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G <-- Y :-
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	matlab_call(Y,G).
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learn_parameters(Items, Tables) :-
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	run_all(Items),
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	clpbn_flag(solver, OldSolver, bnt),
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	clpbn_flag(bnt_model, Old, tied),
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	attributes:all_attvars(AVars),
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	% sort and incorporte evidence
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	clpbn_vars(AVars, AllVars),
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	length(AllVars,NVars),
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	create_bnt_graph(AllVars, Reps),
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	mk_sample(AllVars,NVars,EvVars),
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	bnt_learn_parameters(NVars,EvVars),
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	get_parameters(Reps, Tables),
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	clpbn_flag(solver, bnt, OldSolver),
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	clpbn_flag(bnt_model, tied, Old).
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run_all([]).
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run_all([G|Gs]) :-
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	call(user:G),
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	run_all(Gs).
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clpbn_vars(Vs,BVars) :-
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	get_clpbn_vars(Vs,CVs),
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	keysort(CVs,KVs),
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	merge_vars(KVs,BVars).
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get_clpbn_vars([],[]).
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get_clpbn_vars([V|GVars],[K-V|CLPBNGVars]) :-
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	clpbn:get_atts(V, [key(K)]), !,
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	get_clpbn_vars(GVars,CLPBNGVars).
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get_clpbn_vars([_|GVars],CLPBNGVars) :-
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	get_clpbn_vars(GVars,CLPBNGVars).
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merge_vars([],[]).
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merge_vars([K-V|KVs],[V|BVars]) :-
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	get_var_has_same_key(KVs,K,V,KVs0),
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	merge_vars(KVs0,BVars).
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get_var_has_same_key([K-V|KVs],K,V,KVs0) :- !,
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	get_var_has_same_key(KVs,K,V,KVs0).
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get_var_has_same_key(KVs,_,_,KVs).
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mk_sample(AllVars,NVars, LL) :-
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	add2sample(AllVars, LN),
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	length(LN,LL),
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	matlab_initialized_cells( NVars, 1, LN, sample).
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add2sample([], []).
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add2sample([V|Vs],[val(VId,1,Val)|Vals]) :-
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	clpbn:get_atts(V, [evidence(Ev),dist(Id,_)]), !,
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	bnt:get_atts(V,[bnt_id(VId)]),
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	get_dist_domain(Id, Domain),
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	evidence_val(Ev,1,Domain,Val),
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	add2sample(Vs, Vals).
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add2sample([_V|Vs],Vals) :-
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	add2sample(Vs, Vals).
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evidence_val(Ev,Val,[Ev|_],Val) :- !.
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evidence_val(Ev,I0,[_|Domain],Val) :-
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	I1 is I0+1,
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	evidence_val(Ev,I1,Domain,Val).
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bnt_learn_parameters(_,_) :-
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	engine <-- jtree_inf_engine(bnet),
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%	engine <-- var_elim_inf_engine(bnet),
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%	engine <-- gibbs_sampling_inf_engine(bnet),
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%	engine <-- belprop_inf_engine(bnet),
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%	engine <-- pearl_inf_engine(bnet),
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	bnt_em_max_iter(MaxIters),
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	[new_bnet, trace] <-- learn_params_em(engine, sample, MaxIters).
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get_parameters([],[]).
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get_parameters([Rep-v(_,_,_)|Reps],[CPT|CPTs]) :-
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	get_new_table(Rep,CPT),
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	get_parameters(Reps,CPTs).
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get_new_table(Rep,CPT) :-
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	s <-- struct(new_bnet.'CPD'({Rep})),
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	matlab_get_variable( s.'CPT', CPT).
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