Opened 2 years ago
Last modified 3 months ago
#28704 new defect
Inconsistent cmp for p-adics
Reported by: | saraedum | Owned by: | |
---|---|---|---|
Priority: | minor | Milestone: | sage-9.5 |
Component: | padics | Keywords: | cmp |
Cc: | roed, slelievre, xcaruso | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
As reported in https://ask.sagemath.org/question/48658/possible-bug-in-_cmp_-function/ cmp
is inconsistent for p-adics, i.e., a<b
does not imply b>a
. While ordering p-adics has no deep meaning, it should at least be consistent.
The problem seems to be in ccmp
doing the following
mpz_sub(holder.value, a, b) mpz_mod(holder.value, holder.value, prime_pow.pow_mpz_t_tmp(prec)) return mpz_sgn(holder.value)
But mpz_mod is always non-negative.
Change History (5)
comment:1 Changed 2 years ago by
- Milestone changed from sage-9.0 to sage-9.1
comment:2 Changed 19 months ago by
- Milestone changed from sage-9.1 to sage-9.2
Moving tickets to milestone sage-9.2 based on a review of last modification date, branch status, and severity.
comment:3 Changed 14 months ago by
- Milestone changed from sage-9.2 to sage-9.3
comment:4 Changed 7 months ago by
- Milestone changed from sage-9.3 to sage-9.4
Moving to 9.4, as 9.3 has been released.
comment:5 Changed 3 months ago by
- Milestone changed from sage-9.4 to sage-9.5
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Ticket retargeted after milestone closed