Opened 11 years ago
Closed 6 years ago
#11228 closed defect (fixed)
integer_rational_power problems
Reported by: | gerbicz | Owned by: | AlexGhitza |
---|---|---|---|
Priority: | major | Milestone: | sage-7.4 |
Component: | algebra | Keywords: | |
Cc: | leif, darij, tscrim | Merged in: | |
Authors: | Frédéric Chapoton | Reviewers: | Travis Scrimshaw |
Report Upstream: | N/A | Work issues: | |
Branch: | ff92822 (Commits, GitHub, GitLab) | Commit: | ff92822014f3efa9fc6518b44f20517179535088 |
Dependencies: | Stopgaps: |
Description
The following answers are all wrongs/inconsistent with the documentation:
from sage.rings.rational import integer_rational_power print integer_rational_power(-10, 1/1) print integer_rational_power(-10, 2/2) print integer_rational_power(-10, 4/2) print integer_rational_power(-10, 6/3) print integer_rational_power(0, 0/1) print integer_rational_power(0, 1/2) print integer_rational_power(10, 0/1) sage gives: None None None None 0 0 1 From the first four examples it is clear that sage is unable to observe if b evaluate as an integer when compute a^b for negative "a" value. (the answers should be -10,-10,100,100). The fifth example: as 0^0 is undefined it should return by None. The sixth example: 0^(1/2)=0 is correct but shows that the documentation is broken, because from it: "The positive real root is taken for even denominators.", here 2 is even, but the result 0 is not positive. The seventh example: 10^(0/1)=1 is correct, but from the documentation: "b -- a positive Rational", so change the documentation or return by None.}}}
Change History (6)
comment:1 Changed 8 years ago by
- Status changed from new to needs_info
comment:2 Changed 6 years ago by
- Branch set to u/chapoton/11228
- Cc leif added
- Commit set to ff92822014f3efa9fc6518b44f20517179535088
- Milestone set to sage-7.4
- Status changed from needs_info to needs_review
New commits:
ff92822 | trac 11228 fine details in integer_rational_power
|
comment:4 Changed 6 years ago by
- Reviewers set to Travis Scrimshaw
- Status changed from needs_review to positive_review
muhahahaha
comment:5 Changed 6 years ago by
./sage -Wunused-function
?
(If you want to have further fun, perhaps take a look at rational_power_parts()
in the same file, the only instance in the Sage library where integer_rational_power()
is used at all.)
comment:6 Changed 6 years ago by
- Branch changed from u/chapoton/11228 to ff92822014f3efa9fc6518b44f20517179535088
- Resolution set to fixed
- Status changed from positive_review to closed
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SomeoneTM should check what of the above still applies.