173 lines
		
	
	
		
			5.3 KiB
		
	
	
	
		
			Prolog
		
	
	
	
	
	
			
		
		
	
	
			173 lines
		
	
	
		
			5.3 KiB
		
	
	
	
		
			Prolog
		
	
	
	
	
	
| 
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| :- module(clpbn_connected,
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| 	[clpbn_subgraphs/2,
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| 	influences/4,
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| 	init_influences/3,
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| 	influences/5]).
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| 
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| :- use_module(library(dgraphs),
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| 	[dgraph_new/1,
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| 	dgraph_add_edges/3,
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| 	dgraph_add_vertex/3,
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| 	dgraph_neighbors/3,
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| 	dgraph_edge/3]).
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| 
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| :- use_module(library(rbtrees),
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| 	[rb_new/1,
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| 	rb_insert/4,
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| 	rb_lookup/3]).
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| 
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| :- attribute component/1.
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| 
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| % search for connected components, that is, where we know that A influences B or B influences A.
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| clpbn_subgraphs(Vs, Gs) :-
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| 	mark_components(Vs, Components),
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| 	keysort(Components, Ordered),
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| 	same_key(Ordered, Gs).
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| 
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| % ignore variables with evidence,
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| % the others mark the MB.
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| mark_components([], []).
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| mark_components([V|Vs], Components) :-
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| 	clpbn:get_atts(V, [evidence(_),dist(_,Parents)]), !,
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| 	merge_parents(Parents, _),
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| 	mark_components(Vs, Components).
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| mark_components([V|Vs], [Mark-V|Components]) :-
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| 	mark_var(V, Mark),
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| 	mark_components(Vs, Components).
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| 
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| mark_var(V, Mark) :-
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| 	get_atts(V, [component(Mark)]), !,
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| 	clpbn:get_atts(V, [dist(_,Parents)]), !,
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| 	merge_parents(Parents, Mark).
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| mark_var(V, Mark) :-
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| 	clpbn:get_atts(V, [dist(_,Parents)]), !,
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| 	put_atts(V,[component(Mark)]),
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| 	merge_parents(Parents, Mark).
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| 
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| merge_parents([], _).
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| merge_parents([V|Parents], Mark) :-
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| 	clpbn:get_atts(V,[evidence(_)]), !,
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| 	merge_parents(Parents, Mark).
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| merge_parents([V|Parents], Mark) :-
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| 	get_atts(V,[component(Mark)]), !,
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| 	merge_parents(Parents, Mark).
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| merge_parents([V|Parents], Mark) :-
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| 	put_atts(V,[component(Mark)]),
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| 	merge_parents(Parents, Mark).
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| 
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| 	
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| same_key([],[]).
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| same_key([K-El|More],[[El|Els]|Gs]) :-
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| 	same_keys(More, K, Els, Rest),
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| 	same_key(Rest,Gs).
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| 
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| same_keys([], _, [], []).
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| same_keys([K1-El|More], K, [El|Els], Rest) :-
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| 	K == K1, !,
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| 	same_keys(More, K, Els, Rest).
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| same_keys(Rest, _, [], Rest).
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| 
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| influences_more([], _, _, Is, Is, Evs, Evs, V2, V2).
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| influences_more([V|LV], G, RG, Is0, Is, Evs0, Evs, GV0, GV2) :-
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| 	rb_lookup(V, _, GV0), !,
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| 	influences_more(LV, G, RG, Is0, Is, Evs0, Evs, GV0, GV2).
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| influences_more([V|LV], G, RG, Is0, Is, Evs0, Evs, GV0, GV3) :-
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| 	rb_insert(GV0, V, _, GV1),
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| 	follow_dgraph(V, G, RG, [V|Is0], Is1, [V|Evs0], Evs1, GV1, GV2),
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| 	influences_more(LV, G, RG, Is1, Is, Evs1, Evs, GV2, GV3).
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| 
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| % search for the set of variables that influence V
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| influences(Vs, LV, Is, Evs) :-
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| 	init_influences(Vs, G, RG),
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| 	influences(LV, Is, Evs, G, RG).
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| 
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| init_influences(Vs, G, RG) :-
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| 	dgraph_new(G0),
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| 	dgraph_new(RG0),
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| 	to_dgraph(Vs, G0, G, RG0, RG).
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| 
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| influences([], [], [], _, _).
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| influences([V|LV], Is, Evs, G, RG) :-
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| 	rb_new(V0),
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| 	rb_insert(V0, V, _, V1),
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| 	follow_dgraph(V, G, RG, [V], Is1, [V], Evs1, V1, V2),
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| 	influences_more(LV, G, RG, Is1, Is, Evs1, Evs, V2, _).
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| 
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| to_dgraph([], G, G, RG, RG).
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| to_dgraph([V|Vs], G0, G, RG0, RG) :-
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| 	clpbn:get_atts(V, [evidence(_),dist(_,Parents)]), !,
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| 	build_edges(Parents, V, Edges, REdges),
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| 	dgraph_add_edges(G0,[V-e|Edges],G1),
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| 	dgraph_add_edges(RG0,REdges,RG1),
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| 	to_dgraph(Vs, G1, G, RG1, RG).
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| to_dgraph([V|Vs], G0, G, RG0, RG) :-
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| 	clpbn:get_atts(V, [dist(_,Parents)]),
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| 	build_edges(Parents, V, Edges, REdges),
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| 	dgraph_add_vertex(G0,V,G1),
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| 	dgraph_add_edges(G1, Edges, G2),
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| 	dgraph_add_vertex(RG0,V,RG1),
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| 	dgraph_add_edges(RG1, REdges, RG2),
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| 	to_dgraph(Vs, G2, G, RG2, RG).
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| 
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| 
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| build_edges([], _, [], []).
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| build_edges([P|Parents], V, [P-V|Edges], [V-P|REdges]) :-
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| 	build_edges(Parents, V, Edges, REdges).
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| 
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| follow_dgraph(V, G, RG, Is0, IsF, Evs0, EvsF, Visited0, Visited) :-
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| 	dgraph_neighbors(V, RG, Parents),
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| 	add_parents(Parents, G, RG, Is0, IsI, Evs0, EvsI, Visited0, Visited1),
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| 	dgraph_neighbors(V, G, Kids),
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| 	add_kids(Kids, G, RG, IsI, IsF, EvsI, EvsF, Visited1, Visited).
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| 
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| add_parents([], _, _, Is, Is, Evs, Evs, Visited, Visited).
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| % been here already, can safely ignore.
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| add_parents([V|Vs], G, RG, Is0, IsF, Evs0, EvsF, Visited0, VisitedF) :-
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| 	rb_lookup(V, _, Visited0), !,
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| 	add_parents(Vs, G, RG, Is0, IsF, Evs0, EvsF, Visited0, VisitedF).
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| % evidence node,
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| % just say that we visited it
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| add_parents([V|Vs], G, RG, Is0, IsF, Evs0, EvsF, Visited0, VisitedF) :-
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| 	dgraph_edge(V,e,G), !, % has evidence
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| 	rb_insert(Visited0, V, _, VisitedI),
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| 	add_parents(Vs, G, RG, Is0, IsF, [V|Evs0], EvsF, VisitedI, VisitedF).
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| % non-evidence node,
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| % we will need to find its parents.
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| add_parents([V|Vs], G, RG, Is0, IsF, Evs0, EvsF, Visited0, VisitedF) :-
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| 	rb_insert(Visited0, V, _, VisitedI),
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| 	follow_dgraph(V, G, RG, [V|Is0], IsI, [V|Evs0], EvsI, VisitedI, VisitedII),
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| 	add_parents(Vs, G, RG, IsI, IsF, EvsI, EvsF, VisitedII, VisitedF).
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| 	
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| add_kids([], _, _, Is, Is, Evs, Evs, Visited, Visited).
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| add_kids([V|Vs], G, RG, Is0, IsF, Evs0, EvsF, Visited0, VisitedF) :-
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| 	dgraph_edge(V,e,G), % has evidence
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| 	% we will go there even if it was visited
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| 	( rb_insert(Visited0, V, _, Visited1) ->
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| 	    true
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| 	;
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| 	    % we've been there, but were we there as a father or as a kid?
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| 	    not_in(Evs0, V),
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| 	    Visited1 = Visited0
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| 	),
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| 	!,
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| 	dgraph_neighbors(V, RG, Parents),	
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| 	add_parents(Parents, G, RG, Is0, Is1, [V|Evs0], EvsI, Visited1, VisitedI),	
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| 	(Is1 = Is0 ->
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| 	    % ignore whatever we did with this node,
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| 	    % it didn't lead anywhere (all parents have evidence).
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| 	    add_kids(Vs, G, RG, Is0, IsF, [V|Evs0], EvsF, Visited1, VisitedF)
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| 	;
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| 	    % insert parents
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| 	    add_kids(Vs, G, RG, Is1, IsF, EvsI, EvsF, VisitedI, VisitedF)
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| 	).
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| add_kids([_|Vs], G, RG, Is0, IsF, Evs0, EvsF, Visited0, VisitedF) :-
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| 	add_kids(Vs, G, RG, Is0, IsF, Evs0, EvsF, Visited0, VisitedF).
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| 	
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| 
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| not_in([V1|_], V) :- V1 == V, !, fail.
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| not_in([_|Evs0], V) :-
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| 	not_in(Evs0, V).
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| 
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| 
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