Opened 8 weeks ago
Last modified 3 weeks ago
#28630 new defect
Wrong conversion from fricas
Reported by: | tmonteil | Owned by: | |
---|---|---|---|
Priority: | major | Milestone: | sage-9.0 |
Component: | symbolics | Keywords: | FriCAS |
Cc: | hemmecke, whuss, rws, chapoton, mantepse | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | Reported upstream. Developers acknowledge bug. | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
As reported on this ask question, we have:
sage: f = polylog(3, x) sage: f.integral(x, algorithm='fricas') -x*%iint(x, -log(-x + 1)/x) - (x - 1)*log(-x + 1) + x*polylog(3, x) + x
So, fricas
produces something that is ill-interpreted as some %iint
symbolic function.
Note that maxima
produces the following answer:
sage: f.integral(x, algorithm='maxima') -x*dilog(x) - (x - 1)*log(-x + 1) + x*polylog(3, x) + x
Change History (7)
comment:1 Changed 8 weeks ago by
- Cc hemmecke whuss rws chapoton added
comment:2 Changed 8 weeks ago by
- Keywords FriCAS added
comment:3 Changed 8 weeks ago by
- Cc mantepse added
comment:4 Changed 8 weeks ago by
comment:5 Changed 3 weeks ago by
More a reminder to myself: SageMath's dilog(x)
is FriCAS' dilog(1-x)
. This is properly reflected in sage.functions.log.py
, in class Function_dilog
.
So FriCAS should simplify %iint(x, -log(1-x)/x))
to FriCAS dilog(1-x)
.
comment:6 Changed 3 weeks ago by
- Report Upstream changed from N/A to Reported upstream. No feedback yet.
I reported this at
https://groups.google.com/forum/#!topic/fricas-devel/olmzqJ6IJsE
comment:7 Changed 3 weeks ago by
- Report Upstream changed from Reported upstream. No feedback yet. to Reported upstream. Developers acknowledge bug.
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This seems to be some kind of bug in Fricas:
And the first term can be differentiated (inside Fricas) correctly.