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1. oscargus

   added

   topic: mplot3d

   status: has patchpatch suggested, PR still neededpatch suggested, PR still needed

   on Mar 8, 2022
2. oscargus commented on Mar 8, 2022

   

   oscargus

   on Mar 8, 2022

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   The warning occurs the first time x21 and y21 both are 0 (so it is a divide by zero error).

   A simple way fix it is to change the code to something like:

       if x21 != 0 or y21 != 0:
           u = (x01*x21 + y01*y21) / (x21**2 + y21**2)
           u = np.clip(u, 0, 1)
       else:
           u = 0   # Actually doesn't matter since it will be multiplied by zero anyway...
   

   although the preferred syntax may differ.
3. patquem commented on Mar 8, 2022

   

   patquem

   on Mar 8, 2022

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   thanks @oscargus fror your reply
   there is this other possibility :

   with np.errstate(divide='ignore'):
       u = (x01*x21 + y01*y21) / (x21**2 + y21**2)
   

   Whatever, I think one of this bugfix should be push in the next release.
   Could you please be in charge of that ?
   Thanks,
   Patrick
4. oscargus commented on Mar 8, 2022

   

   oscargus

   on Mar 8, 2022 via email

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   That is indeed a better solution. I can create a PR. Thanks!
5. oscargus commented on Mar 9, 2022

   

   oscargus

   on Mar 9, 2022

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   Seems like one should use invalid='ignore' as although there is a division by zero, the actual warning is "Invalid..." (probably because it is 0/0). For now, I went with my approach (as I didn't figure out the answer above until after pushing it...), but we'll see what the review leads to.

   Reacted by patquem
6. anntzer commented on Mar 10, 2022

   

   anntzer

   on Mar 10, 2022

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   The warning is triggered when trying to get xyz coordinates for the mouse cursor and one of the axes is exactly orthogonal to the screen, but I wonder whether printing xyz coordinates in the toolbar even makes sense at all? Basically, we pick an arbitrary screen-z-depth for the cursor (based on the distance to the edges -- which is where the warning comes from) and print the corresponding xyz value, but if one e.g. carefully looks at the displayed xyz values while slowly moving the mouse across a (default, non-ortho) 3d axes, one will see that the value suddenly jumps when the mouse goes from "closer to one axis" to "closer to another axis".
   In other words, I would suggest to just stop displaying mouse cursor xyz values here. (Also compare with e.g. mayavi, which doesn't display them either.)

   Reacted by Oscar Gustafsson, patquem and Tim Hoffmann
7. WeatherGod commented on Mar 10, 2022

   

   WeatherGod

   on Mar 10, 2022 via email

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   Displaying the (estimated) 3D pointer coordinates has been a feature in mplot3d for over 10 years. The code that is used to compute this estimate has been reused in other projects as well, and when this feature has broken for other reasons, users have noticed and complained. I see no reason to get rid of it entirely. Now, if a better algorithm for computing the estimated coordinates can be devised, all the better!

   …

   On Thu, Mar 10, 2022 at 6:17 AM Antony Lee ***@***.***> wrote: The warning is triggered when trying to get xyz coordinates for the mouse cursor and one of the axes is exactly orthogonal to the screen, but I wonder whether printing xyz coordinates in the toolbar even makes sense at all? Basically, we pick an arbitrary screen-z-depth for the cursor (based on the distance to the edges -- which is where the warning comes from) and print the corresponding xyz value, but if one e.g. carefully looks at the displayed xyz values while slowly moving the mouse across a (default, non-ortho) 3d axes, one will see that the value suddenly jumps when the mouse goes from "closer to one axis" to "closertto another axis". In other words, I would suggest to just stop displaying mouse cursor xyz values here. — Reply to this email directly, view it on GitHub <#22624 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AACHF6HGWOEACZLOBBB4EBLU7HK4TANCNFSM5QG3L5RA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

   Reacted by Thomas A Caswell
8. anntzer commented on Mar 10, 2022

   

   anntzer

   on Mar 10, 2022

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   I am not convinced the values make sense at all. For example, these are the xyz values printed when dragging the mouse across window (default 3d view) horizontally, along the middle y position:

   from pylab import *
   from matplotlib.backend_bases import LocationEvent
   rcdefaults(); rcParams["axes.unicode_minus"] = False  # use ascii minus
   fig = figure()
   ax = fig.add_subplot(projection="3d")
   fig.canvas.draw()
   xyzs = []
   screen_ry = .5
   # drag mouse across window horizontally, along the middle y position
   for screen_rx in np.linspace(0, 1, 1001):
       screen_xy = fig.transFigure.transform((screen_rx, screen_ry))
       pseudo_xy = ax.transData.inverted().transform(screen_xy)
       ev = LocationEvent("", fig.canvas, *screen_xy)
       ev.xdata, ev.ydata = pseudo_xy
       if any([axis.pane.contains(ev)[0] for axis in ax._axis_map.values()]):
           s = ax.format_coord(*pseudo_xy)  # formatted string
           xyzs.append([float(part.split("=")[1]) for part in s.split(",")])  # displayed xyz
       else:  # out of Axes
           xyzs.append((np.nan, np.nan, np.nan))
   xyzs = array(xyzs)
   close(fig)
   plot(xyzs[:, 0], label="x")
   plot(xyzs[:, 1], label="y")
   plot(xyzs[:, 2], label="z")
   legend()
   show()

   

   The jumping is... not nice.
9. anntzer commented on Mar 16, 2022

   

   anntzer

   on Mar 16, 2022

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   when this feature has broken for other reasons, users have noticed and complained

   Actually, I have quickly skimmed through the issue list and didn't find anything related, but perhaps you have refs e.g. on the mailing list?
10. WeatherGod commented on Mar 20, 2022

    

    WeatherGod

    on Mar 20, 2022

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    Ok, so I am also having difficulty finding what I was thinking of, but, here are some issues where people expressed interest in having access to 3D coordinate information:

    #16156
    #11309
    https://discourse.matplotlib.org/t/no-zdata-in-motion-notify-event-when-using-a-3d-plot/16201

    This isn't a comprehensive listing of such interest, and it shows that users find the information that is displayed by format_coords() to be useful enough to want to know more about how to get it programmatically. While I haven't had time to look closely at what you showed above, that isn't an argument to get rid of it; it is an argument to make it better behaved.
11. anntzer commented on Mar 20, 2022

    

    anntzer

    on Mar 20, 2022

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    I don't disagree with making it better behaved. However, the value currently displayed is simply worse than useless, it is misleading (it does not correspond to the dot they are pointing to).
12. tacaswell

    added this to the v3.5.2 milestone on Mar 31, 2022
13. timhoffm

    closed this as completedin #22628on Mar 31, 2022