A (very) strange story:
I married a widow(W) who has a daughter(D). My father(F) married my stepdaughter (D). My wife gave birth to a son(s1). The wife of my father (the stepdaughter) also had a son (s2).
The goal of this project is to input:
grandfather(i,i).
and return yes in prolog.
Here is what I have so far:
%facts
father(f,i).
husband(i,w).
husband(f,d).
mother(w,d).
mother(w,s1).
father(i,s1).
mother(d,s2).
father(f,s2).
%rules
father(X,Y) :- f_in_law(X,Y).
father(X,Y) :- husband(X,Z),mother(Z,Y).
f_in_law(X,Y) :- husband(Z,Y),father(X,Z).
b_in_law(X,Y) :- husband(Z,Y),brother(X,Z).
%brother(X,Y) :- b_in_law(X,Y).
uncle(X,Y) :- father(Z,Y),brother(X,Z).
grandfather(X,Y) :- father(Z,Y),father(X,Z).
I traced through it to see what went wrong. father(f,i) is true so that's good! But father(i,f) is thought of as false. Any suggestions/ideas on how to correct this? I appreciate any input as I am rather new to prolog.
Should the predicate be
f_in_law(X,Y) :- husband(Y,Z),father(X,Z).
instead of
f_in_law(X,Y) :- husband(Z,Y),father(X,Z).
I have reformulated the riddle
father(i, s1).
father(f, i).
father(f, s2).
fatlaw(X, Y) :- husband(X, Z), mother(Z, Y).
mother(w, d).
mother(w, s1).
mother(d, s2).
motlaw(X, Y) :- husband(Z, X), father(Z, Y).
husband(i, w).
husband(f, d).
grandfather(X, Y) :-
( father(X, Z) ; fatlaw(X, Z) )
, ( father(Z, Y) ; fatlaw(Z, Y) ; mother(Z, Y) ; motlaw(Z, Y) )
.
the point seems to be that grandfather must accept fake biological offsprings (I hope this is reasonable English).
with that
?- grandfather(X,X).
X = i ;
false.
Related
This is my prolog file.
male(bob).
male(john).
female(betty).
female(dana).
father(bob, john).
father(bob, dana).
mother(betty, john).
mother(betty, dana).
husband(X, Y) :- male(X), mother(Y, Z), father(X, Z).
wife(X, Y) :- female(X), father(Y, Z), mother(X, Z).
son(X, Y) :- male(X), mother(Y, X);female(X), father(Y, X).
daughter(X, Y) :- female(X), mother(Y, X);female(X), father(Y, X).
sister(X, Y) :- female(X), mother(Z, X), mother(Z, Y), X \= Y.
brother(X, Y) :- male(X), mother(Z, X), mother(Z, Y), X \= Y.
I want a name of rule if it returns true for any value x or y.
Let's say x = betty and y = john.
mother(betty, john). <- this will meet so my rule should return 'mother'.
Similarly if any other rule or fact meets true for some value x, y it should return that rule name.
How can I achieve something like that?
could be easy as
query_family(P1, P2, P) :-
% current_predicate(P/2),
member(P, [father, mother, husband, wife, son, daughter, sister, brother]),
call(P, P1, P2).
that gives
?- query_family(betty, john, R).
R = mother ;
false.
?- query_family(betty, X, R).
X = john,
R = mother ;
X = dana,
R = mother ;
X = bob,
R = wife ;
X = bob,
R = wife ;
false.
the semicolon after the answer means 'gimme next'
$ swipl
?- ['facts'].
?- setof( Functor,
Term^(member(Functor, [father, mother, husband, wife, son, daughter, sister, brother]),
Term =.. [Functor, betty, john],
once(Term)),
Answer).
Answer = [mother].
?-
If you want to avoid having to specify the list of functors of interest, you could use current_predicate(F/2).
I am writing a program to return true if a person is another persons second cousin once removed. The only information that is known is who is the parent of who else. I am using the family tree from here http://en.wikipedia.org/wiki/Cousin#Second_cousins_once_removed. Overall I got everything working but i cant make it find the second cousin once removed. The first cousin and the once removed ones work, just looking to get some help on how to find a second cousin that is also once removed.
parent(adam, betty).
parent(agatha, betty).
parent(adam, charles).
parent(agatha, charles).
parent(bill, david).
parent(betty, david).
parent(charles, emma).
parent(corinda, emma).
parent(dawn, frank).
parent(david, frank).
parent(emma, gwen).
parent(eric, gwen).
parent(frank, harry).
parent(felicity, harry).
child(X, Y) :-
parent(Y, X).
grandparent(X, Y) :-
parent(X, Z),
parent(Z, Y).
greatgrandparent(X, Y) :-
parent(P, Y),
grandparent(X, P).
cousin(X, Y) :-
grandparent(Z, X),
grandparent(Z, Y),
\+sibling(X, Y),
X \= Y.
sibling(X, Y) :-
parent(Z, X),
parent(Z, Y),
X \= Y.
cousinonceremoved(X, Y) :-
cousin(Z, Y),
child(X, Z).
secondcousin(X, Y) :-
greatgrandparent(Z, X),
greatgrandparent(Z, Y),
\+sibling(X, Y),
\+cousin(X, Y),
X \= Y.
Just as stated in the article: "The child of one's second cousin".
secondCousinOnceRemoved(H, G) :- child(H, F), secondcousin(F, G).
Using recursion i need to find all blood relatives of any person in the family tree.
My attempt so far has failed.
Here is my code, with my attempt at the bottom
female(helen).
female(debbie).
female(louise).
female(yvonne).
female(belinda).
female(heather).
male(john).
male(andrew).
male(barry).
male(daniel).
male(charles).
parent(helen, debbie).
parent(helen, barry).
parent(helen, louise).
parent(john, debbie).
parent(john, barry).
parent(andrew, louise).
parent(debbie, yvonne).
parent(debbie, daniel).
parent(barry, charles).
parent(barry, belinda).
parent(louise, heather).
mother(X, Y) :-
female(X),
parent(X, Y).
father(X, Y) :-
male(X),
parent(X,Y).
child(X, Y) :-
parent(Y, X).
daughter(X, Y) :-
parent(Y, X),
female(X).
son(X, Y) :-
parent(Y,X),
male(X).
sister(X, Y) :-
female(X),
parent(Q,X),
parent(Q,Y).
brother(X, Y) :-
male(X),
parent(Q,X),
parent(Q,Y).
sibling(X, Y) :-
parent(Q,X),
parent(Q,Y),
X\=Y.
uncle(X, Y) :-
parent(P,Y),
brother(X,P).
aunt(X, Y) :-
parent(P,Y),
sister(X,P).
cousin(C, Cousin):-
parent(Parent,C),
sibling(Parent,AU),
child(Cousin,AU).
%Here is Relative
relative(An, Re):-
An\=Re,
parent(An, Re);
sibling(An, Re).
relative(An, Rela):-
parent(An, Child);
sibling(An, Rela),
relative(Child, Rela),
An\=Rela, C\=Rela.
Sort of works, but gets stuck in an infinite loop at the end.
Thanks.
not sure about 'relatives' (any person bound reachable in a parent/child relation ?), but your definition seems more complex than needed ( do you know what ; does ?).
I tried
relative(An, Re):-
parent(An, Re).
relative(An, Rela):-
parent(An, C),
relative(C, Rela).
that yields
16 ?- forall(relative(X,Y),writeln(X:Y)).
helen:debbie
helen:barry
helen:louise
john:debbie
john:barry
andrew:louise
debbie:yvonne
debbie:daniel
barry:charles
barry:belinda
louise:heather
helen:yvonne
helen:daniel
helen:charles
helen:belinda
helen:heather
john:yvonne
john:daniel
john:charles
john:belinda
andrew:heather
true.
edit I tried another relation, using a generalized parent/2, but still too permissive.
relative(Pers, Re):-
ancestor(Re, Pers) ; sibling(Pers, Re) ; cousin(Pers, Re) ; uncle(Re, Pers) ; aunt(Re, Pers).
ancestor(Anc, Pers) :- parent(Anc, Pers).
ancestor(Anc, Pers) :- parent(Anc, P), ancestor(P, Pers).
Maybe cousin/2 is too permissive also. Here is the graph
I guess that heather should have only luise,helen,andrew as relatives. It's this true ?
edit given latest comment, seems that the definition could be right. I get
24 ?- setln(X,relative(heather,X)).
andrew
barry
belinda
charles
daniel
debbie
helen
louise
yvonne
true.
that is everyone is related to heather apart john.
Here's one way that works, but it will sometimes produce duplicates. Using setof will give the unique collection. I avoided the miscellaneous relations and stuck with descendent or parent.
descendent(A, B) :-
parent(B, A).
descendent(A, B) :-
parent(C, A),
descendent(C, B).
relative(A, B) :-
descendent(B, A).
relative(A, B) :-
descendent(A, B).
relative(A, B) :-
descendent(A, C),
descendent(B, C),
A \= B.
setof(A, relative(heather, A), Relatives).
Relatives = [andrew,barry,belinda,charles,daniel,debbie,helen,louise,yvonne]
If you don't have setof, you can use the findall/3 and sort/2 ISO predicates:
findall(A, relative(heather, A), R), sort(R, Relatives).
Note that the solutions presented so far assume that all of the relatives have unique names. A general case of dealing with relatives with the same first name (and possibly the same last name) you would need to track and compare lineages for differences.
I am struggling to get my head around this basic Prolog concept.
I understand that the basic clause for determining the ancestor of a person is as follows:
ancestor(X, Y) :- parent(X, Y).
ancestor(X, Y) :- parent(X, Z), ancestor(Z, Y).
However, I am trying to get my head around how this works for a prolog program that implements lists to determine children of a parent, i.e:
parent_of(simon, [matthew, andrea, joanne]).
To determine wether or not somebody is the father of somebody, I am using this which works perfectly:
father_of(X, Y) :- parent_of(X, List), my_member(Y, List), male(X).
However, I cant seem to figure out how to get this to work for the ancestor clause above.
member/2 it's the simpler relation between an element and a list:
ancestor_of(X, Y) :- parent_of(X, Ys), member(Y, Ys).
ancestor_of(X, Y) :- parent_of(X, Zs), member(Z, Zs), ancestor_of(Z, Y).
I've added a relation to test the transitive rule
parent_of(simon, [matthew, andrea, joanne]).
parent_of(andrea, [bill, joan]).
yields
?- ancestor_of(andrea,A).
A = bill ;
A = joan ;
false.
?- ancestor_of(simon,A).
A = matthew ;
A = andrea ;
A = joanne ;
A = bill ;
A = joan ;
false.
?- ancestor_of(X,bill).
X = andrea ;
X = simon ;
false.
I have to write a small prolog program which checks if a given person is a ancestor of a second one.
These are the facts and rules:
mother(tim, anna).
mother(anna, fanny).
mother(daniel, fanny).
mother(celine, gertrude).
father(tim, bernd).
father(anna, ephraim).
father(daniel, ephraim).
father(celine, daniel).
parent(X,Y) :- mother(X,Y).
parent(X,Y) :- father(X,Y).
The test if a person is an ancestor of another person is easy:
ancestor(X, Y) :- parent(X, Y).
ancestor(X, Y) :- parent(X, Z), ancestor(Z, Y).
But now I have to write a method ancestor(X,Y,Z) which also prints out the relationship between two persons. It should look like this
?- ancestor(ephraim, tim, X).
false.
?- ancestor(tim, ephraim, X).
X = father(mother(tim)).
And that is the problem: I have no clue how do to this.
You can use an accumulator to adapt #Scott Hunter's solution :
mother(anna, fanny).
mother(daniel, fanny).
mother(celine, gertrude).
father(tim, bernd).
father(anna, ephraim).
father(daniel, ephraim).
father(celine, daniel).
ancestor(X, Y, Z) :- ancestor(X, Y, X, Z).
ancestor(X, Y, Acc, father(Acc)) :- father(X, Y).
ancestor(X, Y, Acc, mother(Acc)) :- mother(X, Y).
ancestor(X, Y, Acc, Result) :-
father(X, Z),
ancestor(Z, Y, father(Acc), Result).
ancestor(X, Y, Acc, Result) :-
mother(X, Z),
ancestor(Z, Y, mother(Acc), Result).
edit : as Scott Hunter showed in his edit, there's no need for an explicit accumulator here, since we can left the inner part of the term unbound easily at each iteration. His solution is therefore better !
A term manipulation alternative to the accumulator tecnique by #Mog:
parent(X, Y, mother(X)) :- mother(X, Y).
parent(X, Y, father(X)) :- father(X, Y).
ancestor(X, Y, R) :-
parent(X, Y, R).
ancestor(X, Y, R) :-
parent(X, Z, P),
ancestor(Z, Y, A),
eldest(A, P, R).
eldest(A, P, R) :-
A =.. [Af, Aa],
( atom(Aa)
-> T = P
; eldest(Aa, P, T)
),
R =.. [Af, T].
To test, I made tim a father: father(ugo, tim).
?- ancestor(tim, ephraim, X).
X = father(mother(tim)) .
?- ancestor(ugo, ephraim, X).
X = father(mother(father(ugo))) .
Simply add a term which tracts what kind of parent is used at each step (edited to get result in proper order):
ancestor(X,Y,father(X)) :- father(X,Y).
ancestor(X,Y,mother(X)) :- mother(X,Y).
ancestor(X,Y,father(Z2)) :- father(Z,Y), ancestor(X,Z,Z2).
ancestor(X,Y,mother(Z2)) :- mother(Z,Y), ancestor(X,Z,Z2).