| Karim Belabas on Fri, 24 Jan 2025 18:11:40 +0100 |
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| Re: equality of t_INTMODs |
* Max Alekseyev [2025-01-24 17:56]:
> Hi Karim,
>
> On "===" vs "==", what are other notable cases when the two give different
> results?
There are many:
? 1. == 0E38 \\ at default precision
%1 = 1
? [] == 0
%2 = 1
? 1 == [1,0,0]~
%3 = 1
? Mod(1,2) == 1
%4 = 1
etc.
> Do I understand correctly, that internally functions in PARI/GP, such as
> setsearch(), rely on "===" rather than "=="?
Mostly yes. They rely on cmp(), which is a universal comparison function.
Mathematically meaningless but transitive, and it guarantees
cmp(x,y) == 0 if and only if x === y
Cheers,
K.B.
--
Pr. Karim Belabas, U. Bordeaux, Vice-président en charge du Numérique
Institut de Mathématiques de Bordeaux UMR 5251 - (+33) 05 40 00 29 77
http://www.math.u-bordeaux.fr/~kbelabas/