Opened 7 years ago
Closed 7 years ago
#9053 closed defect (fixed)
Sage's new generic HNF doesn't quite work right wrt the free modules code
Reported by: | was | Owned by: | jason, was |
---|---|---|---|
Priority: | major | Milestone: | sage-4.7 |
Component: | linear algebra | Keywords: | |
Cc: | minz | Merged in: | sage-4.7.alpha4 |
Authors: | Moritz Minzlaff | Reviewers: | Keshav Kini |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
The last output below should obviously be True, but it is False.
sage: R.<x> = GF(7)[] sage: A = R^3 sage: L = A.span([x*A.0 + (x^3 + 1)*A.1, x*A.2]); L Free module of degree 3 and rank 2 over Univariate Polynomial Ring in x over Finite Field of size 7 Echelon basis matrix: [ x x^3 + 1 0] [ 0 0 x] sage: M = A.span([x*L.0]); M Free module of degree 3 and rank 1 over Univariate Polynomial Ring in x over Finite Field of size 7 Echelon basis matrix: [ x^2 x^4 + x 0] sage: M.0 in L False
Apply trac_9053_fixes_pivots.v2.patch
Attachments (2)
Change History (8)
comment:1 Changed 7 years ago by
- Component changed from algebra to linear algebra
- Owner changed from AlexGhitza to jason, was
Changed 7 years ago by
comment:2 Changed 7 years ago by
- Cc minz added
- Status changed from new to needs_review
comment:3 Changed 7 years ago by
I just reran the above two doctests on a different machine and receieved no doctest failures. *shrug*
comment:4 Changed 7 years ago by
- Reviewers set to Keshav Kini
- Status changed from needs_review to positive_review
I can't replicate your doctest failures. Everything passes on sage.math, except the ever-troublesome devel/sage/sage/tests/startup.py , which I tried again individually with no problems. The fix itself looks good. Reference builds, though how that could be affected I don't know. IIRC all code should be within 79 columns, so I split some lines in this function for you while you're at it. Feel free to rewrite it if it looks ugly, haha.
comment:6 Changed 7 years ago by
- Merged in set to sage-4.7.alpha4
- Resolution set to fixed
- Status changed from positive_review to closed
The bug was a single line in _echelon_form_PID which returned the wrong pivot element for matrices of one row. The attached patch should fix that.
While doctesting all of Sage I received two errors (that seem unrelated?):
The first apparently also came up during discussions on #9390. The doctest failure in sage0.py "randomly" appeared or not when I reran the test mutiple times. I'm not quite sure what to make of this...