failure-slice

问题 Clue Four guests (Colonel Mustard, Professor Plum, Miss Scarlett, Ms. Green) attend a dinner party at the home of Mr. Boddy. Suddenly, the lights go out! When they come back, Mr Boddy lies dead in the middle of the table. Everyone is a suspect. Upon further examination, the following facts come to light: Mr Boddy was having an affair with Ms. Green. Professor Plum is married to Ms. Green. Mr. Boddy was very rich. Colonel Mustard is very greedy. Miss Scarlett was also having an affair with Mr.

问题 The term fib(N,F) is true when F is the N th Fibonacci number. The following Prolog code is generally working for me: :-use_module(library(clpfd)). fib(0,0). fib(1,1). fib(N,F) :- N #> 1, N #=< F + 1, F #>= N - 1, F #> 0, N1 #= N - 1, N2 #= N - 2, F1 #=< F, F2 #=< F, F #= F1 + F2, fib(N1,F1), fib(N2,F2). When executing this query (in SICStus Prolog), the first (and correct) match is found for N (rather instantly): | ?- fib(X,377). X = 14 ? When proceeding (by entering ";") to see if there are

问题 I am trying to make a function that splits a list of variable length into three lists of even length in order. The following splits it into three, but processes inserts them into each list one at a time. An example of what I want is: [1, 2, 3, 4, 5] -> [1, 2], [3, 4], [5] Another example would be: [8, 7, 6, 5, 4, 3, 2, 1] -> [8, 7, 6], [5, 4, 3], [2, 1]. The following code splits them by inserting into each list one at a time: div([], [], [], []). div([X], [X], [], []). div([X,Y], [X], [Y], [

问题 I am trying to implement a dcg that takes a set of strings of the form {a,b,c,d}*.The problem i have is if I have a query of the form s([a,c,b],[]),It returns true which is the right answer but when i have a query of the form s([a,c,f],[]),It does not return an answer and it runs out of local stack. s --> []. s --> s,num. num --> [a]. num--> [b]. num--> [c]. num--> [d]. 回答1: Use phrase/2 Let's try phrase(s,[a,b,c]) in place of s([a,b,c],[]) . The reason is very simple: In this manner we are

问题 I'm given the following program: edge(a,b). edge(b,c). edge(a,d). path(N,M):- path(N,New),edge(New,M). path(N,M):- edge(N,M). And asked if when applying a proof tree algorithm to the following query: ?- path(a,X). the proof tree is an infinite success tree, or an infinite failure tree? Now as I see it, during the building of the tree, you get stuck in applying rule 1 of path over and over again, creating an infinite tree and never getting to rule 2 of path.. thus creating an infinite failure

问题 I can't figure out where this is going wrong. Please note that I am very new to Prolog and I'm sure I'm missing something - just no idea what that might be. Could anyone help me out please? Thanks, here is my code: printSentence([]). printSentence([W|[]]) :- write(W), write('.'), nl. printSentence([W|R]) :- write(W), write(' '), printSentence(R). transform([], Result). transform([Word|Rest], Result) :- replace(Word, Replacement), append(Result, Replacement, NewResult), transform(Rest,

问题 I have the following problem: Define a predicate sorted(LL) , that is satisfied when the list LL contains other lists that are sorted in order of increasing length. For example: ?- sorted([[],[1],[1,1],[1,1,1]]) -> yes. ?- sorted([[],[1],[1,1]]) -> yes. ?- sorted([[1],[],[1,1],[1,1,1]]) -> no. And I have this code so far: % shorter/2 shorter([],_). shorter([_|T1], [_|T2]) :- shorter(T1,T2). % sorted/1 sorted([]). sorted([_]). sorted([L1,L2 | T]) :- shorter2(L1, L2), sorted([L2,T]). The

问题 I'd like my program to find me all sub-sets of size K of the integers 1,2,...,N. For this, I wrote the following subs(N,X,Y) means that X is a sub-set of size N of the set Y. I defined the following: subs(0,[],X). subs(N,[A|R1],[A|R2]):-N>0, N1 is N-1, subs(N1,R1,R2). subs(N,[A|R1],[B|R2]):-subs(N,[A|R1],R2). subs(N,[A|R1],[B|R2]):-subs(N,R1,[B|R2]). And then as a check I ran subs(2,X,[1,2,3,4]). I got the first answer [1,2], but never did it give a second answer, as it got stuck in an

问题 I'd like someone to explain this procedure if possible (from the book 'learn prolog now'). It takes two numerals and adds them together. add(0,Y,Y). add(s(X),Y,s(Z)) :- add(X,Y,Z). In principle I understand, but I have a few issues. Lets say I issue the query ?- add(s(s(0)), s(0), R). Which results in: R = s(s(s(0))). Step 1 is the match with rule 2. Now X becomes s(0) and Y is still s(0). However Z (according to the book) becomes s(_G648), or s() with an uninstantiated variable inside it.

问题 Assume we have the following predicates (This is an example from Programming in Prolog): [F0] isInteger(0). [F1] isInteger(X):- isInteger(Y), X is Y+1. The first result for query isInteger(R), the marker is placed at F0, and will return R=0 If user presses ; , the marker is placed at F1, we move to subgoal(isInteger(Y), which is satisfied with F0) and R=1. I understand the above. Now here are my questions: If user presses ; again, where is the marker? How does the search proceed to return R=2