Hello, on a 2019-release of sage, the following behaviour was observed: After defining:
R = Zp(5)
a = R(5, 6)
b = R(10)
an inconsistent output was given for a<b and b>a:
a<b
False
b>a
True
Is this a bug, or should the output not be consistent here for some reason?
P.S: The comparison function is implemented in the file: padic_generic_element.pyx
Thank you.
Ordering of p-adics is not terribly meaningful of course but it should at least be consistent. So I think this is a bug.
If I understood things correctly, the code that eventually runs is:
mpz_sub(holder.value, a, b)
mpz_mod(holder.value, holder.value, prime_pow.pow_mpz_t_tmp(prec))
return mpz_sgn(holder.value)
The problem here is that mpz_mod is always non-negative so mpz_sgn never returns -1.
I created https://trac.sagemath.org/ticket/2870... to track this issue.
Asked: 2019-11-06 21:23:41 +0100
Seen: 291 times
Last updated: Nov 07 '19
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Great, I will use this from now on. thanks.