Opened 12 years ago
Closed 9 years ago
#9046 closed defect (duplicate)
bug in collect and/or term ordering in symbolics
Reported by: | zimmerma | Owned by: | burcin |
---|---|---|---|
Priority: | minor | Milestone: | sage-duplicate/invalid/wontfix |
Component: | symbolics | Keywords: | pynac |
Cc: | kcrisman | Merged in: | |
Authors: | Reviewers: | Burcin Erocal, Paul Zimmermann | |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | #9880 | Stopgaps: |
Description (last modified by )
This seems a bug (note the instances of -x^2
and x^2
):
var('a b x y z') sage: p = -a*x^3 - a*x*y^2 + 2*b*x^2*y + 2*y^3 + x^2*z + y^2*z + x^2 + y^2 + a*x sage: p.collect(x) -a*x^3 + (2*b*y + z + 1)*x^2 - x^2 - (a*y^2 - a)*x + x^2 + 2*y^3 + y^2*z + y^2
Change History (13)
comment:1 Changed 12 years ago by
- Keywords pynac added
comment:2 Changed 11 years ago by
- Cc kcrisman added
- Priority changed from critical to minor
This is not critical.
comment:3 Changed 10 years ago by
- Component changed from calculus to symbolics
- Description modified (diff)
- Summary changed from missing documentation and bug in collect to bug in collect and/or term ordering in symbolics
It turns out that #11839 was opened and did the first part of this ticket, including documenting the expand()
issue.
However, the bug remains, so I'll just change this ticket to be about it.
comment:4 Changed 10 years ago by
With the new description, this is probably a duplicate of #9880. I will check if the pynac changes for that ticket fix this one.
comment:5 Changed 10 years ago by
bug still present in Sage 5.0.
Paul
comment:6 Changed 10 years ago by
- Milestone changed from sage-5.1 to sage-duplicate/invalid/wontfix
- Reviewers set to Burcin Erocal
- Status changed from new to needs_review
This is a duplicate of #9880. With the Pynac patch queue and patches listed on #9880, I get:
sage: var('a b x y z') (a, b, x, y, z) sage: p = -a*x^3 - a*x*y^2 + 2*b*x^2*y + 2*y^3 + x^2*z + y^2*z + x^2 + y^2 + a> sage: p.collect(x) -a*x^3 + (2*b*y + z + 1)*x^2 + 2*y^3 + y^2*z - (a*y^2 - a)*x + y^2
We should close this after adding it as a doctest to #9880.
comment:7 Changed 10 years ago by
- Status changed from needs_review to positive_review
Doctest is in attachment:trac_9880-doctest_for_9046.patch:ticket:9880. This can be closed now.
comment:8 Changed 10 years ago by
- Reviewers changed from Burcin Erocal to Burcin Erocal, Paul Zimmermann
- Status changed from positive_review to needs_work
- Work issues set to correct doctests
Burcin,
first the ticket number is wrong (13107 instead of 9046) then the input p was mangled
(ends with a>
instead of a*x
).
Paul
comment:9 Changed 9 years ago by
- Status changed from needs_work to needs_review
I replaced the patch attached to #9880:
attachment:trac_9880-doctest_for_9046.patch:ticket:9880
I hope I got it right this time. Sorry for the noise.
comment:10 Changed 9 years ago by
comment:11 Changed 9 years ago by
- Dependencies set to #9880
comment:12 Changed 9 years ago by
- Status changed from needs_review to positive_review
That ticket has been merged, so I think this can be closed.
comment:13 Changed 9 years ago by
- Resolution set to duplicate
- Status changed from positive_review to closed
- Work issues correct doctests deleted
Here is the same session using GiNaC directly via
ginsh
:It seems that one needs to call
expand()
explicitly before callingcollect()
. I think this should just be documented in the docstring.The problem with
-x^2 + x^2
appearing in the output is probably a bug I introduced while playing with the ordering of the terms. I will take a look at it when I find a chance. It's likely to be later than a week though.