Ticket #12277 (closed defect: duplicate)
Warnings in `plot_slope_field`
|Reported by:||novoselt||Owned by:||jason, was|
|Report Upstream:||N/A||Reviewers:||Karl-Dieter Crisman, Andrey Novoseltsev|
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.
- Status changed from new to needs_review
- Description modified (diff)
- Milestone changed from sage-5.0 to sage-duplicate/invalid/wontfix
- Reviewers set to Karl-Dieter Crisman, Andrey Novoseltsev