[問題] PROLOG
由於第一次接觸PROLOG，所以語法不熟，不知道怎麼除錯..
可以請大大幫我看一下嗎?謝謝~
% Candidate Elimination Algorithm
run_candidate_elim :- candidate_elim([[_,_,_]], [],
[[small, medium, large], [red, blue, green], [ball, brick, cube]]).
% Candidate_elim implements a top level read-process loop
% It prints out the current G set
% the S set
%
% and calls process to process the input.
candidate_elim([G],[S],_) :-
covers(G,S),covers(S,G),
write("target concept is "), write(G),nl.
candidate_elim(G, S, Types) :-
write("G= "), write(G),nl,
write("S= "), write(S),nl,
write("Enter Instance "),
read(Instance),
process(Instance, G, S, Updated_G, Updated_S, Types),
candidate_elim(Updated_G, Updated_S, Types).
% Process takes the instance,
% a set of concepts, G and
% and a set of concepts, S
% it implements a step of the candidate elimination algorithm.
process(negative(Instance), G, S, Updated_G, Updated_S, Types) :-
delete(X, S, covers(X, Instance), Updated_S),
specialize_set(G,Spec_G, Instance, Types),
delete(X, Spec_G, (member(Y, Spec_G), more_general(Y, X)), Pruned_G),
delete(X, Pruned_G, (member(Y, Updated_S), not(covers(X, Y))), Updated_G).
process(positive(Instance), G, [], Updated_G, [Instance],_):-
% Initialize S
delete(X, G, not(covers(X, Instance)), Updated_G).
process(positive(Instance), G, S, Updated_G, Updated_S,_) :-
delete(X, G, not(covers(X, Instance)), Updated_G),
generalize_set(S,Gen_S, Instance),
delete(X, Gen_S, (member(Y, Gen_S), more_general(X, Y)), Pruned_S),
delete(X, Pruned_S, not((member(Y, Updated_G), covers(Y, X))), Updated_S).
process(Input, G, P, G, P,_):-
Input \= positive(_),
Input \= negative(_),
write("Enter either positive(Instance) or negative(Instance) "), nl
% The following predicate definitions are duplicated in either
% the general to specific searches or the specific to genearal searches.
%
specialize_set([], [], _, _).
ERROR: c:/candidate1.pl:54:0: Syntax error: Operator expected
specialize_set([Hypothesis|Rest],Updated_H,Instance, Types):-
covers(Hypothesis, Instance),
(bagof(Hypothesis, specialize(Hypothesis, Instance, Types), Updated_head); Updated_head = []),
specialize_set(Rest, Updated_rest, Instance, Types),
append(Updated_head, Updated_rest, Updated_H).
specialize_set([Hypothesis|Rest],[Hypothesis|Updated_rest],Instance, Types):-
not (covers(Hypothesis, Instance)),
specialize_set(Rest,Updated_rest, Instance, Types).
specialize([Prop|_], [Inst_prop|_], [Instance_values|_]):-
var(Prop),
member(Prop, Instance_values),
Prop \= Inst_prop.
specialize([_|Tail], [_|Inst_tail], [_|Types]):-
specialize(Tail, Inst_tail, Types).
%
generalize_set([], [], _).
generalize_set([Hypothesis|Rest],Updated_H,Instance):-
not(covers(Hypothesis, Instance)),
(bagof(X, generalize(Hypothesis, Instance, X), Updated_H); Updated_head = []),
generalize_set(Rest,Updated_rest, Instance),
append(Updated_head, Updated_rest, Updated_H).
generalize_set([Hypothesis|Rest],[Hypothesis|Updated_rest],Instance):-
covers(Hypothesis, Instance),
generalize_set(Rest,Updated_rest, Instance).
%
generalize([],[],[]).
generalize([Feature|Rest], [Inst_prop|Rest_inst], [Feature|Rest_gen]) :-
not(Feature \= Inst_prop),
generalize(Rest, Rest_inst, Rest_gen).
generalize([Feature|Rest], [Inst_prop|Rest_inst], [_|Rest_gen]) :-
Feature \= Inst_prop,
generalize(Rest, Rest_inst, Rest_gen).
% more_general(Feature_vector_1, Feature_vector_2) :- succeeds if
% Feature_vector_1 is strictly more general than Feature_vector_2
more_general(X, Y) :- not(covers(Y, X)), covers(X, Y).
% covers(Feature_list_1, Feature_list_2) :- Succeeds if Feature_list_1
% covers Feature_list_2. Note that covers, unlike unification is
% not symmetric: variables in Feature_list_2 will not match constants
% in Feature_list_1.
covers([],[]).
covers([H1|T1], [H2|T2]) :-
var(H1), var(H2),
covers(T1, T2).
covers([H1|T1], [H2|T2]) :-
var(H1), atom(H2),
covers(T1, T2).
covers([H1|T1], [H2|T2]) :-
atom(H1), atom(H2), H1 = H2,
covers(T1, T2).
% delete(Element, List1, Goal, List2) :- List2 contains all bindings
% of Element to a member of List1 except those that cause
% Goal to succeed
delete(X, L, Goal, New_L) :-
(bagof(X, (member(X, L), not(Goal)), New_L);New_L = []).
麻煩大家了~謝謝!!
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 140.121.219.142
※ 編輯: ntouckcm 來自: 140.121.219.142 (05/24 10:43)
※ 編輯: ntouckcm 來自: 140.121.219.142 (05/24 10:44)
推
05/26 14:09, , 1F
05/26 14:09, 1F
討論串 (同標題文章)