In place of not(X = Y) you need to write \+ X = Y or X \= Y. But consider to use dif(X,Y) instead. dif/2 is present in B, SWI, YAP, SICStus. To see the difference: ?- X = b, dif(a, X). X = b. ?- X = b, \+ a = X. X = … Read more
TL;DR: Don’t. The cut prunes Prolog’s search tree. That is, given a pure Prolog program without cut and the same program with cuts the only difference is that the program with cuts might spend less time in fruitless branches, and thus is more efficient ; might have fewer answers ; it might also terminate whereas … Read more
Preface In Prolog, CLP(FD) constraints are the right choice for solving such scheduling tasks. See clpfd for more information. In this case, I suggest using the powerful global_cardinality/2 constraint to restrict the number of occurrences of each round, depending on the number of available courts. We can use iterative deepening to find the minimal number of admissible … Read more
How about defining path/4 like this? path(R_2, Xs, A,Z) :- % A path `Xs` from `A` to `Z` is … walk(R_2, Xs, A,Z), % … a walk `Xs` from `A` to `Z` … all_dif(Xs). % … with no duplicates in `Xs`. To aid universal termination, we swap the two goals in above conjunction … path(R_2, … Read more
According to Wikipedia, the following versions of Prolog have Java interfaces. I’ve linked to the main pages for them: BProlog Ciao Prolog SICStus Prolog SWI Prolog TuProlog (implemented in Java) LPA Prolog Good luck with your search!
What are the names of the algorithms and concepts used in Prolog? Logic programming Depth-first, backtracking search Unification See Sterling & Shapiro, The Art of Prolog (MIT Press) for the theory behind Prolog. Probably it builds some kind of tree structure or directed object graph, and then upon queries it traveres that graph with a … Read more
Backward chaining (a la Prolog) is more like finding what initial conditions form a path to your goal. At a very basic level it is a backward search from your goal to find conditions that will fulfil it. Backward chaining is used for interrogative applications (finding items that fulfil certain criteria) – one commercial example … Read more
Prolog mode for (X)Emacs. See http://bruda.ca/emacs-prolog/
Single quoted items are always atoms. The meaning of double quotes depends on the Prolog flag double_quotes: atom — with this value “a” = a. Nowadays, this is rarely used. But you will find Prolog books where [“abc.pl”] is written. codes — a list of character codes. This is frequently the default, but it leads … Read more
avs_term_rearranged(AVs, T, AVsR) :- term_variables(T, Vs), copy_term(Vs+AVs, Vs1+AVs1), bind_names(AVs1), build_vn_list(Vs, Vs1, AVsR). bind_names([]). bind_names([N=V|AVs]) :- N = V, bind_names(AVs). build_vn_list([], [], []). build_vn_list([V|Vs],[N|Ns],NVs) :- ( atom(N) -> NVs = [N=V|NVs1] ; var(N) -> NVs = NVs1 ), build_vn_list(Vs, Ns, NVs1).