Opened 11 years ago
Last modified 7 years ago
#8341 new defect
detect_poles doesn't find a vertical asymptote where both sides go to infinity
Reported by: | jason | Owned by: | was |
---|---|---|---|
Priority: | major | Milestone: | sage-6.4 |
Component: | graphics | Keywords: | |
Cc: | whuss, robert.marik | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
It seems like this should show a vertical asymptote at x=1, but it doesn't:
plot(1/((x-1)^2), (x, -3.5, 3.5), detect_poles='show', ymin = -5, ymax = 5)
Change History (6)
comment:1 Changed 11 years ago by
- Cc robert.marik added
comment:2 Changed 8 years ago by
See also #3985.
comment:3 Changed 8 years ago by
- Milestone changed from sage-5.11 to sage-5.12
comment:4 Changed 7 years ago by
- Milestone changed from sage-6.1 to sage-6.2
comment:5 Changed 7 years ago by
- Milestone changed from sage-6.2 to sage-6.3
comment:6 Changed 7 years ago by
- Milestone changed from sage-6.3 to sage-6.4
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It would be nice to fix this. But current detect_poles simply skips the lines with slope close to pi/2 and draws the vertical asyptote, if the function changes sign (skips from -infinity to +infinity). I think that using this idea it is not possible to detect vertical asymptote.
Just some attempts: If we drop the condition which requires change in sign, we get "interval of asymptotes" - the asymptote is too thick. Making epsilon smaller introduces problems with other graphs.
This is the diff with my experiments, if someone is interested