/* From the book PROLOG PROGRAMMING IN DEPTH by Michael A. Covington, Donald Nute, and Andre Vellino. Copyright 1988 Scott, Foresman & Co. Non-commercial distribution of this file is permitted. */ /* Modified for Quintus Prolog by Andreas Siebert */ % get1(C) % accepts a line of input and returns only the first character. % A good way to obtain a 1-character response from the user % in a Prolog with buffered input, such as Quintus or ALS. :- multifile get1/1. get1(C) :- get(C), repeat, get0(N), (N=10 ; N=13), !. /* CONMAN.PL */ /* * Requires procedures defined in files * WRITELN.PL, YES.PL, and FINDALL.PL. */ :- ( clause(writeln(_),_) ; consult('writeln.pl') ). :- ( clause(yes(_),_) ; consult('yes.pl') ). :- ( clause(find_all(_),_) ; consult('findall.pl') ). :- dynamic known/3. /* * CONMAN user interface * CONMAN modifies and extends the standard Prolog infer- * ence engine, providing the ability to use confidence * factors in reaching conclusions. As a result, we dis- * tinguish the procedures in CONMAN that handle communi- * cation with the user from the predicates that make up * the CONMAN inference engine. */ conman :- kb_intro(Statement), writeln(Statement),nl, kb_threshold(T), kb_hypothesis(Hypothesis), confidence_in([Hypothesis,yes],CF), CF >= T, write('Conclusion: '), writeln(Hypothesis), write('Confidence in hypothesis: '), write(CF), writeln('%.'), explain_conclusion(Hypothesis), fail. conman :- kb_hypothesis(Hypothesis), confirm([Hypothesis]),!, writeln('No further conclusions.'), nl, finish_conman. conman :- writeln('Can draw no conclusions.'), nl, finish_conman. finish_conman :- abolish(known,3), write('Do you want to conduct another consultation?'), yes('>'), nl, nl, asserta(known(xxx,yyy,zzz)), /* dummy predicate */ !, conman. finish_conman :- asserta(known(xxx,yyy,zzz)). /* dummy predicate */ ask_confidence(Hypothesis,CF) :- kb_can_ask(Hypothesis), writeln('Is the following conjecture true? --'), write(' '), writeln(Hypothesis), writeln(['Possible responses: ', ' (y) yes (n) no', ' (l) very likely (v) very unlikely', ' (p) probably (u) unlikely', ' (m) maybe (d) don''t know.', ' (?) why?']), write(' Your response --> '), get0_only([y,l,p,m,n,v,u,d,?],Reply), nl, nl, convert_reply_to_confidence(Reply,CF), !, Reply \== d, ask_confidence_aux(Reply,Hypothesis,CF). ask_confidence_aux(Char,_,_) :- Char \== ?, !. ask_confidence_aux(_,Hypothesis,CF) :- explain_question, !, ask_confidence(Hypothesis,CF). get0_only(List,Reply) :- get1(Char), % Some Prologs can use get0 here name(Value,[Char]), member(Value,List),Reply = Value, !. get0_only(List,Result) :- put(7), write(' [Invalid response. Try again.] '), get0_only(List,Result). convert_reply_to_confidence(?,_). convert_reply_to_confidence(d,_). convert_reply_to_confidence(n,0). convert_reply_to_confidence(v,5). convert_reply_to_confidence(u,25). convert_reply_to_confidence(m,60). convert_reply_to_confidence(p,80). convert_reply_to_confidence(l,90). convert_reply_to_confidence(y,100). explain_question :- current_hypothesis(Hypothesis), writeln( 'I need this information to test the following hypothesis:'), writeln(Hypothesis), nl, writeln('Do you want further explanation?'), explain_question_aux,!. explain_question :- writeln('This is a basic hypothesis.'), nl, wait. explain_question_aux :- \+ yes('>'), nl, nl, !. explain_question_aux :- nl, nl, fail. explain_conclusion(Hypothesis) :- writeln('Do you want an explanation?'), yes('>'), nl, nl, explain_conclusion_aux(Hypothesis), wait, !. explain_conclusion(_) :- nl, nl. explain_conclusion_aux([]) :- !. explain_conclusion_aux([Hypothesis,_]) :- !, explain_conclusion_aux(Hypothesis). explain_conclusion_aux([and,[Hypothesis,_],Rest]) :- !, explain_conclusion_aux(Hypothesis), explain_conclusion_aux(Rest). explain_conclusion_aux([or,[Hypothesis,_],Rest]) :- !, explain_conclusion_aux(Hypothesis), explain_conclusion_aux(Rest). explain_conclusion_aux(Hypothesis) :- known(Hypothesis,CF,user), kb_threshold(T),CF >= T, !, write(Hypothesis),writeln(' -'), write('From what you told me, I accepted this with '), write(CF),writeln('% confidence.'), nl. explain_conclusion_aux(Hypothesis) :- known(Hypothesis,CF,user), !, DisCF is 100 - CF, write(Hypothesis),writeln(' -'), write('From what you told me, I rejected this with '), write(DisCF),writeln('% confidence.'), nl. explain_conclusion_aux(Hypothesis) :- known(Hypothesis,50,no_evidence), !, write(Hypothesis),writeln(' -'), writeln( 'Having no evidence, I assumed this was 50-50.'), nl. explain_conclusion_aux(Hypothesis) :- !, known(Hypothesis,CF1,[CF,Prerequisites,Conditions]), writeln(Hypothesis),write('Accepted with '), write(CF1), writeln('% confidence on the basis of the following'), write('Rule: '),writeln(Hypothesis), write(' with confidence of '), write(CF), writeln('% if'), list_prerequisites(Prerequisites), list_conditions(Conditions), nl, explain_conclusion_aux(Conditions). list_prerequisites([]) :- !. list_prerequisites([-,Hypothesis|Rest]) :- !, write(' is disconfirmed: '), writeln(Hypothesis), list_prerequisites(Rest). list_prerequisites([Hypothesis|Rest]) :- write(' is confirmed: '), writeln(Hypothesis), list_prerequisites(Rest). list_conditions([]) :- !. list_conditions([and,Hypothesis,Rest]) :- list_conditions(Hypothesis), list_conditions(Rest). list_conditions([or,Hypothesis,Rest]) :- writeln(' ['), list_conditions(Hypothesis), writeln(' or'), list_conditions(Rest), writeln(' ]'). list_conditions([Hypothesis,yes]) :- write(' to confirm: '), writeln(Hypothesis). list_conditions([Hypothesis,no]) :- write(' to disconfirm: '), writeln(Hypothesis). wait :- write('Press Return when ready to continue. '), get0(_), nl, nl. % Even ALS can use get0 here /* * CONMAN inference engine * The CONMAN inference engine computes the confidence in * compound goals and decides which of several rules best * support a conclusion. It remembers this information for * later use by itself, the main conman procedure, and the * explanatory facilities. */ confidence_in([],100) :- !. confidence_in([Hypothesis,yes],CF) :- known(Hypothesis,CF,_), !. confidence_in([Hypothesis,yes],CF) :- ask_confidence(Hypothesis,CF), !, assert(known(Hypothesis,CF,user)). confidence_in([Hypothesis,yes],CF) :- asserta(current_hypothesis(Hypothesis)), find_all(X,evidence_that(Hypothesis,X),List), find_all(C,member([C,_],List),CFList), retract(current_hypothesis(_)), CFList \== [], !, maximum(CFList,CF), member([CF,Explanation],List), assert(known(Hypothesis,CF,Explanation)). confidence_in([Hypothesis,yes],50) :- assert(known(Hypothesis,50,no_evidence)), !. confidence_in([Hypothesis,no],CF) :- !, confidence_in([Hypothesis,yes],CF0), CF is 100 - CF0. confidence_in([and,Conjunct1,Conjunct2],CF) :- !, confidence_in(Conjunct1,CF1), confidence_in(Conjunct2,CF2), minimum([CF1,CF2],CF). confidence_in([or,Disjunct1,Disjunct2],CF) :- !, confidence_in(Disjunct1,CF1), confidence_in(Disjunct2,CF2), maximum([CF1,CF2],CF). evidence_that(Hypothesis,[CF,[CF1,Prerequisite,Condition]]):- c_rule(Hypothesis,CF1,Prerequisite,Condition), confirm(Prerequisite), confidence_in(Condition,CF2), CF is (CF1 * CF2)//100. confirm([]). confirm([-,Hypothesis|Rest]) :- !, known(Hypothesis,CF,_), kb_threshold(T), M is 100 - CF, M >= T, confirm(Rest). confirm([Hypothesis|Rest]) :- known(Hypothesis,CF,_), kb_threshold(T),CF >= T, !, confirm(Rest). minimum([M,K],M) :- M < K, ! . minimum([_,M],M). maximum([],0) :- !. maximum([M],M) :- !. maximum([M,K],M) :- M >= K, !. maximum([M|R],N) :- maximum(R,K), maximum([K,M],N). append([],X,X). append([X|Y],Z,[X|W]) :- append(Y,Z,W). member(X,[X|_]). member(X,[_|Z]) :- member(X,Z).