Opened 3 years ago
Closed 2 years ago
#20752 closed defect (wontfix)
Wrong simplification in symbolic trigonometry involving fractions
Reported by: | tmonteil | Owned by: | |
---|---|---|---|
Priority: | major | Milestone: | sage-duplicate/invalid/wontfix |
Component: | symbolics | Keywords: | |
Cc: | rws | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
As reported in this ask question, Sage makes wrong simplifications in symbolic trigonometry involving fractions:
sage: cos(pi+pi*1/42) cos(1/42*pi)
While it should be -cos(1/42*pi)
.
Change History (10)
comment:1 Changed 3 years ago by
comment:2 Changed 3 years ago by
I do not have intermediate versions of Sage with me, but i confirm that it is a regression since on Sage 5.12, we have:
sage: cos(pi+pi*1/42) cos(43/42*pi) sage: sin(pi+pi/42) sin(43/42*pi)
comment:3 Changed 3 years ago by
No, the changes were just a few months ago, will get to it tomorrow.
comment:4 follow-up: ↓ 7 Changed 3 years ago by
More precisely, on a 7.2.beta4 version of Sage which i can reach by ssh, it works well:
sage: cos(pi+pi*1/42) cos(43/42*pi) sage: sin(pi+pi*1/42) sin(43/42*pi)
So the regression is very recent, could it be due to the last update of pynac/ginac ?
comment:5 Changed 3 years ago by
- Description modified (diff)
- Summary changed from Wrong simplification in symbolic trigonometry to Wrong simplification in symbolic trigonometry involving fractions
comment:6 Changed 3 years ago by
- Component changed from porting: Solaris to symbolics
comment:7 in reply to: ↑ 4 Changed 3 years ago by
So the regression is very recent, could it be due to the last update of pynac/ginac ?
Almost certainly so. See e.g. this bug, though I assume it is a different particular one.
comment:8 Changed 3 years ago by
- Milestone changed from sage-7.3 to sage-duplicate/invalid/wontfix
- Status changed from new to needs_review
This is fixed and doctested in #20742.
comment:9 Changed 3 years ago by
- Status changed from needs_review to positive_review
comment:10 Changed 2 years ago by
- Resolution set to wontfix
- Status changed from positive_review to closed
Determined to be invalid/duplicate/wontfix (closing as "wontfix" as a catch-all resolution).
Same with
sin(pi+pi/42)
.