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patham9/gist:58b63d02717b034822f0bb92cced97fd

Created October 3, 2025 08:23
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Behavior of once(concurrent_and( vs. first_solution(
Raw
gistfile1.txt
%Finding divisors
'find-divisor'(A, B, C) :-
*(B, B, D),
>(D, A, E),
( E==true
-> C=A
; C=F,
'%'(A, B, G),
==(0, G, H),
( H==true
-> F=B
; F=I,
+(B, 1, J),
'find-divisor'(A, J, I)
)
).
%In order to check if a number is prime:
'prime?'(A, B) :-
'find-divisor'(A, 2, C),
==(A, C, B).
%%% Arithmetic & Comparison: %%%
'+'(A,B,R) :- R is A + B.
'*'(A,B,R) :- R is A * B.
'%'(A,B,R) :- R is A mod B.
'>'(A,B,R) :- (A>B -> R=true ; R=false).
'=='(A,B,R) :- (A==B -> R=true ; R=false).
%%For test output:
test(A,B,R) :- (A == B -> E = '✅' ; E = '❌'),
format(string(R), "is ~w, should ~w. ~w ~n", [A, B, E]),
writeln(R).
%First approach:
branch_to_goal(Out, (Goal,Res), (Goal, Out=Res)).
maplist_firstsolution(A) :-
maplist(branch_to_goal(B),
[ ('prime?'(5353725700019, C), C),
('prime?'(5378181100003, D), D),
('prime?'(5421844300001, E), E),
('prime?'(5473443100001, F), F)
],
G),
first_solution(B, G, []),
test(B, true, A).
%Second approach:
once_concurrentand(A) :-
once(concurrent_and(member((B, C),
[ ('prime?'(535372570000000063, D), D),
('prime?'(537818110000000001, E), E),
('prime?'(5421844300001, F), F),
('prime?'(547344310000000013, G), G)
]),
(call(B), H=C))),
test(H, true, A).
%Invoke both:
:- maplist_firstsolution(A), once_concurrentand(B).
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