农民山羊狼白菜拼图的Prolog专家系统

时间:2014-05-06 01:28:22

标签: prolog expert-system river-crossing-puzzle

我的任务是在Prolog中创建一个通用专家系统,你可以插入不同的知识库,所以它必须是通用的。我必须在专家系统中提供的知识库是Farmer Goat Wolf和Cabbage Puzzle。我在设计知识库和一般推理引擎时非常困难。

经过几天的搜索,我找到了一系列专家系统的例子,用于鸟类等级和其他一些可能的结果,但它们似乎无法帮助我解决这个问题。一起投射。

我只是想知道是否有人有一些很好的例子或材料如何在Prolog中设计专家系统或者哪里有好看的地方?

感谢您的帮助,非常感谢。

PS。我宁愿不购买材料,因为这是我上学的最后一个月,在这门课程结束后,我不大可能会做很多Prolog编程。

谢谢和问候,

d

修改

这是我的知识库。

% Order is Farmer, Goat, Wolf, Cabbage
start_state :: state(west_side, west_side, west_side, west_side).

fact :: current(X, X, X, X) :- 
    end_state :: state(X, X, X, X),
    X = east_side.

move_goat ::
    if
        state(X, X, W, C) and
        opp(X, Y) and
        (unsafe(state(Y, Y, W, C)))
    then
        current(Y, Y, W, C).

move_wolf ::
    if
        state(X, G, X, C) and
        opp(X, Y) and
        (unsafe(state(Y, G, Y, C)))
    then
        current(Y, G, Y, C).

move_cabbage ::
    if
        state(X, G, W, X) and
        opp(X, Y) and
        (unsafe(state(Y, G, W, Y)))
    then
        current(Y, G, W, Y).

% Move the object to the other side of the river
opp(west_side, east_side).
opp(east_side, west_side).

% Is the new state unsafe
fact :: unsafe(state(X,Y,Y,C)) :- opp(X,Y).
fact :: unsafe(state(X,Y,W,Y)) :- opp(X,Y).

这是专家系统我试图改进我的知识库。

:-op(900, xfx, ::).
:-op(800, xfx, was).
:-op(880, xfx, then).
:-op(870, fx, if).
:-op(600, xfx, from).
:-op(600, xfx, by).
:-op(550, xfy, or).
:-op(540, xfy, and).
:-op(300, fx, 'derived by').

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
main :-
    consult('FarmerKB.pl'),
    assertz(lastindex(0)),
    assertz(wastold(dummy, false, 0)),
    assertz(end_answers(dummy)),
    expert.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

expert :-
    getquestion(Question),
    ( answeryes(Question)
        ;
        answerno(Question)
    ).

answeryes(Question) :-
    markstatus(negative),
    explore(Question, [], Answer),
    positive(Answer),
    markstatus(positive),
    present(Answer), nl,
    write('More Solutions?'),
    getreply(Reply),
    Reply = no.

answerno(Question) :-
    retract(no_positive_answer_yet), !,
    explore(Question, [], Answer),
    negative(Answer),
    present(Answer), nl,
    write('More Negative Solutions?'),
    getreply(Reply),
    Reply = no.

markstatus(negative) :-
    assertz(no_positive_answer_yet).

markstatus(positive) :-
    retract(no_positive_answer_yet), !
    ;
    true.

getquestion(Question) :-
    nl, write('Question Please'), nl,
    read(Question).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

explore(Goal, Trace, Goal is true was 'found as a fact') :-
    fact :: Goal.

explore(Goal, Trace, Goal is TruthValue was 'derived by' Rule from Answer) :-
    Rule :: if Condition then Goal,
    explore(Condition, [Goal by Rule | Trace], Answer),
    truth(Answer, TruthValue).

explore(Goal1 and Goal2, Trace, Answer) :- !,
    explore(Goal1, Trace, Answer1),
    continue(Answer1, Goal1 and Goal2, Trace, Answer).

explore(Goal1 or Goal2, Trace, Answer) :-
    exploreyes(Goal1, Trace, Answer)
    ;
    exploreyes(Goal2, Trace, Answer).

explore(Goal1 or Goal2, Trace, Answer1 and Answer2) :- !,
    not(exploreyes(Goal1, Trace, _)),
    not(exploreyes(Goal2, Trace, _)),
    explore(Goal1, Trace, Answer1),
    explore(Goal2, Trace, Answer2).

explore(Goal, Trace, Goal is Answer was told) :-
    useranswer(Goal, Trace, Answer).

exploreyes(Goal, Trace, Answer) :-
    explore(Goal, Trace, Answer),
    positive(Answer).

continue(Answer1, Goal1 and Goal2, Trace, Answer) :-
    positive(Answer1),
    explore(Goal2, Trace, Answer2),
    ( positive(Answer2),
        Answer = Answer1 and Answer2
        ;
        negative(Answer2),
        Answer = Answer2
    ).

continue(Answer1, Goal1 and Goal2, _, Answer1) :-
    negative(Answer1).

truth(Question is TruthValue was found, TruthValue) :- !.

truth(Answer1 and Answer2, TruthValue) :-
    truth(Answer1, true),
    truth(Answer2, true), !,
    TruthValue = true
    ;
    TruthValue = false.

positive(Answer) :-
    truth(Answer, true).

negative(Answer) :-
    truth(Answer, false).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

getreply(Reply) :-
    read(Answer),
    means(Answer, Reply), !
    ;
    nl, write('Answer unknown, try again please'), nl,
    getreply(Reply).

means(yes, yes).
means(y, yes).
means(no, no).
means(n, no).
means(why, why).
means(w, why).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

useranswer(Goal, Trace, Answer) :-
    askable(Goal, _),
    freshcopy(Goal, Copy),
    useranswer(Goal, Copy, Trace, Answer, 1).

useranswer(Goal, _, _, _, N) :-
    N > 1,
    instantiated(Goal), !,
    fail.

useranswer(Goal, Copy, _, Answer, _) :-
    wastold(Copy, Answer, _),
    instance_of(Copy, Goal), !.

useranswer(Goal, _, _, true, N) :-
    wastold(Goal, true, M),
    M >= N.

useranswer(Goal, Copy, _, Answer, _) :-
    end_answers(Copy),
    instance_of(Copy, Goal), !,
    fail.

useranswer(Goal, _, Trace, Answer, N) :-
    askuser(Goal, Trace, Answer, N).

askuser(Goal, Trace, Answer, N) :-
    askable(Goal, ExternFormat),
    format(Goal, ExternFormat, Question, [], Variables),
    ask(Goal, Question, Variables, Trace, Answer, N).

ask(Goal, Question, Variables, Trace, Answer, N) :-
    nl,
    ( Variables = [], !,
        write('Is it true:')
        ;
        write('Any (more) solution to:')
    ),
    write(Question), write('?'),
    getreply(Reply), !,
    process(Reply, Goal, Question, Variables, Trace, Answer, N).

process(why, Goal, Question, Variables, Trace, Answer, N) :-
    showtrace(Trace),
    ask(Goal, Question, Variables, Trace, Answer, N).

process(yes, Goal, _, Variables, Trace, true, N) :-
    nextindex(Next),
    Next1 is Next + 1,
    ( askvars(Variables),
        assertz(wastold(Goal, true, Next))
        ;
        freshcopy(Goal, Copy),
        useranswer(Goal, Copy, Trace, Answer, Next1)
    ).

process(no, Goal, _, _, _, false, N) :-
    freshcopy(Goal, Copy),
    wastold(Copy, true, _), !,
    assertz(end_answers(Goal)),
    fail
    ;
    nextindex(Next),
    assertz(wastold(Goal, false, Next)).

format(Var, Name, Name, Vars, [Var/Name | Vars]) :-
    var(Var), !.

format(Atom, Name, Atom, Vars, Vars) :-
    atomic(Atom), !,
    atomic(Name).

format(Goal, Form, Question, Vars0, Vars) :-
    Goal =..[Functor | Args1],
    Form =..[Functor | Forms],
    formatall(Args1, Forms, Args2, Vars0, Vars),
    Question =..[Functor | Args2].

formatall([], [], [], Vars, Vars).

formatall([X | XL], [F | FL], [Q | QL], Vars0, Vars) :-
    formatall(XL, FL, QL, Vars0, Vars1),
    format(X, F, Q, Vars1, Vars).

askvars([]).

askvars([Variable/Name | Variables]) :-
    nl, write(Name), write(' = '),
    read(Variable),
    askvars(Variables).

showtrace([]) :-
    nl, write('This was you question'), nl.

showtrace([Goal by Rule | Trace]) :-
    nl, write('To investigate, by'),
    write(Rule), write(','),
    write(Goal),
    showtrace(Trace).

instantiated(Term) :-
    numbervars(Term, 0, 0).

instance_of(Term, Term1) :-
    freshcopy(Term1, Term2),
    numbervars(Term2, 0, _), !,
    Term = Term2.

freshcopy(Term, FreshTerm) :-
    asserta(copy(Term)),
    retract(copy(FreshTerm)), !.

nextindex(Next) :-
    retract(lastindex(Last)), !,
    Next is Last + 1,
    assertz(lastindex(Next)).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

present(Answer) :-
    nl, showconclusion(Answer),
    nl, write('Would you like to see how?'),
    getreply(Reply),
    ( Reply = yes, !,
        show(Answer)
        ;
        true
    ).

showconclusion(Answer1 and Answer2) :- !,
    showconclusion(Answer1), write('and '),
    showconclusion(Answer2).

showconclusion(Conclusion was Found) :-
    write(Conclusion).

show(Solution) :-
    nl, show(Solution0), !.

show(Answer1 and Answer2, H) :- !,
    show(Answer1, H),
    tab(H), write(and), nl,
    show(Answer2, H).

show(Answer was Found, H) :-
    tab(H), writeans(Answer),
    nl, tab(H),
    write('was '),
    show1(Found, H).

show1(Derived from Answer, H) :- !,
    write(Derived), write('from'),
    nl, H1 is H + 4,
    show(Answer, H1).

show1(Found, _) :-
    write(Found), nl.

writeans(Goal is true) :- !,
    write(Goal).

writeans(Answer) :-
    write(Answer).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% Negate the current statement
not(P) :-
    P, !, fail
    ;
    true.

谢谢,

d

1 个答案:

答案 0 :(得分:0)

对于那些正在努力解决类似问题的人,我能够使用amzi.com和George Luger的例子中的教程,为农民和山羊问题提供一个有效的知识库/专家系统。

http://www.amzi.com/ExpertSystemsInProlog/xsiptop.php

http://www.cs.unm.edu/~luger/
http://www.cs.unm.edu/~luger/ai-final/code/

由于这是最艰难的部分,我只发布知识库。

rule((move(St1, Cu1) :- 
    (start(state(St1, St2, St3, St4)),
    switch(state(St1, St2, St3, St4), state(Cu1, Cu2, Cu3, Cu4), [state(St1, St2, St3, St4)]))), 100).

start(state(east_side, east_side, east_side, east_side)).
end(state(west_side, west_side, west_side, west_side)).

switch(state(F1, G1, W1, C1), state(F2, G2, W2, C2), History) :-
    is_end(state(F1, G1, W1, C1))
    ;
    move_state(state(F1, G1, W1, C1), state(F2, G2, W2, C2)),
    not(is_history(state(F2, G2, W2, C2), History)),
    switch(state(F2, G2, W2, C2), state(F3, G3, W3, C3), [state(F2, G2, W2, C2)|History]).

move_state(state(X,X,W,C), state(Y,Y,W,C)) :- 
    opp(X,Y), not(unsafe(state(Y,Y,W,C))).
move_state(state(X,G,X,C), state(Y,G,Y,C)) :- 
    opp(X,Y), not(unsafe(state(Y,G,Y,C))).
move_state(state(X,G,W,X), state(Y,G,W,Y)) :- 
    opp(X,Y), not(unsafe(state(Y,G,W,Y))).
move_state(state(X,G,W,C), state(Y,G,W,C)) :- 
    opp(X,Y), not(unsafe(state(Y,G,W,C))).

opp(east_side, west_side).
opp(west_side, east_side).

unsafe(state(X, Y, Y, C)) :- opp(X, Y).
unsafe(state(X, Y, W, Y)) :- opp(X, Y).

is_end(state(F1, G1, W1, C1)) :-
    end(state(Side1, Side2, Side3, Side4)),
    Side1 == F1, Side2 == G1, 
    Side3 == W1, Side4 == C1.

is_history(state(F1, G1, W1, C1), []) :-
    fail.
is_history(state(F1, G1, W1, C1), [HisHead|HisTail]) :-
    state(F1, G1, W1, C1) == HisHead
    ;
    is_history(state(F1, G1, W1, C1), HisTail).

% This has to be added if there are no ask-able questions otherwise the program will fail
askable(test).