Ticket #12277 (closed defect: duplicate)
Warnings in `plot_slope_field`
| Reported by: | novoselt | Owned by: | jason, was |
|---|---|---|---|
| Priority: | major | Milestone: | sage-duplicate/invalid/wontfix |
| Component: | graphics | Keywords: | |
| Cc: | jason | Work issues: | |
| Report Upstream: | N/A | Reviewers: | Karl-Dieter Crisman, Andrey Novoseltsev |
| Authors: | Merged in: | ||
| Dependencies: | Stopgaps: |
Description (last modified by novoselt) (diff)
Duplicate of #11208
If I do (in Sage 4.7.2 or 4.8.alpha6)
plot_slope_field(1, (1,2), (3,4))
(or anything else that I have tried), then in front of the plot, which looks as expected, I get
Warning: divide by zero encountered in divide Warning: invalid value encountered in multiply Warning: invalid value encountered in multiply Warning: divide by zero encountered in divide Warning: invalid value encountered in multiply Warning: invalid value encountered in multiply
My investigation so far shows: this function is a little wrapper for plot_vector_field which sets new defaults for three options. If headlength is set to 0, there are warnings.
A possible workaround is to set it to something small: 0.001 seems to work on the screen. However, since with headaxislength=0 and headlength=0.2 I definitely see "a hair on the end", it does not seem to be satisfactory from a perfectionist point of view (and producing vector formats that may be scaled or printed with high resolution).
Besides, current settings do produce the accurate plot, it just shows warnings that should not be there, and I have no idea how to fix it.
Change History
comment:2 follow-up: ↓ 3 Changed 17 months ago by jason
Ah yes, #11915. Do you still see the problem after applying that spkg?
comment:5 Changed 17 months ago by novoselt
- Status changed from new to needs_review
- Description modified (diff)
- Milestone changed from sage-5.0 to sage-duplicate/invalid/wontfix
Yes, strange I couldn't find it, I tried to search... My current workaround is that I have redefined plot_slope_field. It is in a way good, since I also had to fix aspect ratio (for 4.7.2) and changed defaults for colour and frame to match the textbook I am using.
comment:7 Changed 17 months ago by novoselt
Am I supposed to do anything with author/reviewer fields?
It seems like I remember that this was fixed in the new matplotlib 1.1.0 release (an spkg is up on trac somewhere).