Question

以下是我的决策树的Prolog程序，它根据输入的名称给出输出油或电信或计算机（该人的投资选项：高油风险，电信 - 中等风险，计算机稳定风险）， marital_status，收入和抵押贷款。但是我收到了错误！ moderate_risk（X）： - ask_marital_status（X，Y），Y =已婚，ask_income（X，I）， I =＆lt; 50000，ask_mortgage（X，Z），Z =＆lt; 50000，！。

moderate_risk(X):-ask_marital_status(X,M),M=married,ask_income(X,I), I>50000,!.


moderate_risk(X):-ask_marital_status(X,M), M=single, ask_income(X,I), I=<35000,!.


stable_risk(X):-ask_marital_status(X,M), M=married, ask_income(X,I), I=<50000,


                ask_mortgage(X,Z), Z>50000,!.


stable_risk(X):-ask_marital_status(X,M), M=single, ask_income(X,I), I>35000,  


                        ask_age(X,A),A>50,!.


high_risk(X):-ask_marital_status(X,M), M=single, ask_income(X,I), I>35000,



                     ask_age(X,A),A=<50,!.


invest(X,oil):-stable_risk(X),!.


invest(X,telecommunications):-moderate_risk(X),!.


invest(X,computers):-high_risk(X),!.

main(X,Z):-var(X), write('what is your name?'),read(X), invest(X,Z),!.


main(X,Z):-invest(X,Z),!.


ask_marital_status(X,Y):-marital_status(X,Y).


ask_marital_status(X,Y):-not(marital_status(X,Y)), write('what is your marital



  status:married or single?'), read(Y), asserta(marital_status(X,Y)).


    ask_income(X,Y):-income(X,Y).


ask_income(X,Y):-not(income(X,Y)),write('what is your annual income?'), read(Y),


asserta(income(X,Y)).


ask_mortgage(X,Z):-mortgage(X,Z).


ask_mortgage(X,Z):-not(mortgage(X,Z)),write('what is your remaining mortgage?'),


 read(Z), asserta(mortgage(X,Z)).


ask_age(X,A):-not(age(X,A)).


ask_age(X,A):-not(age(X,A)), write('what is your age?'), read(A), asserta(age(X,A)).

Answer 1

这是我尝试编译时得到的结果：

Warning: The predicates below are not defined. If these are defined
Warning: at runtime using assert/1, use :- dynamic Name/Arity.
Warning: 
Warning: age/2, which is referenced by
Warning:    /home/bvassile/Documents/code/prolog/marital.pl:80:16: 1-st clause of ask_age/2
Warning:    /home/bvassile/Documents/code/prolog/marital.pl:81:19: 2-nd clause of ask_age/2
Warning: income/2, which is referenced by
Warning:    /home/bvassile/Documents/code/prolog/marital.pl:70:19: 1-st clause of ask_income/2
Warning:    /home/bvassile/Documents/code/prolog/marital.pl:71:22: 2-nd clause of ask_income/2
Warning: marital_status/2, which is referenced by
Warning:    /home/bvassile/Documents/code/prolog/marital.pl:64:4: 1-st clause of ask_marital_status/2
Warning:    /home/bvassile/Documents/code/prolog/marital.pl:66:8: 2-nd clause of ask_marital_status/2
Warning: mortgage/2, which is referenced by
Warning:    /home/bvassile/Documents/code/prolog/marital.pl:75:21: 1-st clause of ask_mortgage/2
Warning:    /home/bvassile/Documents/code/prolog/marital.pl:76:24: 2-nd clause of ask_mortgage/2
true.

因此，我按照警告信息的前两行中的建议，将以下内容添加到文件顶部：

:- dynamic age/2, income/2, marital_status/2, mortgage/2.

我还纠正了ask_age/2定义中的错误。使用此程序（具有更正的格式）：

:- dynamic age/2, income/2, marital_status/2, mortgage/2.

moderate_risk(X) :-
    ask_marital_status(X,Y),
    Y=married,
    ask_income(X,I), I=<50000,
    ask_mortgage(X,Z), Z=<50000,
    !.

moderate_risk(X) :-
    ask_marital_status(X,M),
    M=married,
    ask_income(X,I), I>50000,
    !.

moderate_risk(X) :-
    ask_marital_status(X,M),
    M=single,
    ask_income(X,I), I=<35000,
    !.

stable_risk(X) :-
    ask_marital_status(X,M),
    M=married,
    ask_income(X,I), I=<50000,
    ask_mortgage(X,Z), Z>50000,
    !.

stable_risk(X) :-
    ask_marital_status(X,M),
    M=single,
    ask_income(X,I), I>35000,
    ask_age(X,A), A>50,
    !.

high_risk(X) :-
    ask_marital_status(X,M),
    M=single,
    ask_income(X,I), I>35000,
    ask_age(X,A),A=<50,
    !.

invest(X,oil) :-
    stable_risk(X),
    !.

invest(X,telecommunications) :-
    moderate_risk(X),
    !.

invest(X,computers) :-
    high_risk(X),
    !.

main(X,Z) :-
    var(X),
    write('what is your name?'), read(X),
    invest(X,Z),
    !.
main(X,Z) :-
    invest(X,Z),
    !.

ask_marital_status(X,Y) :-
    marital_status(X,Y).
ask_marital_status(X,Y) :-
    not(marital_status(X,Y)),
    write('what is your marital status:married or single?'), read(Y),
    asserta(marital_status(X,Y)).

ask_income(X,Y) :- income(X,Y).
ask_income(X,Y) :- \+ income(X,Y),
    write('what is your annual income?'), read(Y),
    asserta(income(X,Y)).

ask_mortgage(X,Z) :- mortgage(X,Z).
ask_mortgage(X,Z) :- \+ mortgage(X,Z),
    write('what is your remaining mortgage?'), read(Z),
    asserta(mortgage(X,Z)).

ask_age(X,A) :- age(X,A).
ask_age(X,A) :- \+ age(X,A),
    write('what is your age?'), read(A),
    asserta(age(X,A)).

你会注意到你有一些愚蠢的削减。其中大多数可能是不必要的。特别是在子句末尾的剪辑总是永远不会存在。您可以尝试删除子句末尾的所有剪切，看看这是否会改变程序的行为。我现在可以使用?- main(boris, Z).加载和运行代码。

Answer 2

正如SWI-Prolog告诉你的那样，marital_status/2没有定义。你可以参考：

ask_marital_status(X,Y) :- marital_status(X,Y).

但你从未在任何地方定义它。

Prolog中的决策树

2 个答案: