VPython in JupyterLab not rendering

[John Burk]

I've installed a VPython 7.5 using the command conda install -c vpython vpython to a clean anaconda environment running python 3.6. When I open Jupyterlab (0.35.4) and try to run a program to render a sphere, the sphere() command hangs and no window appears.

When I enter these same commands to a Jupyter Notebook  (5.7.8) running in the same environment, it works, and the sphere is rendered. 

I'd appreciate any suggestions on how to fix this problem. 

Thanks,

-John

[Steve Spicklemire]

Try:

jupyter labextension install vpython

-steve

> On Apr 2, 2019, at 5:07 AM, John Burk <jb...@standrews-de.org> wrote:
>
> I've installed a VPython 7.5 using the command conda install -c vpython vpython to a clean anaconda environment running python 3.6. When I open Jupyterlab (0.35.4) and try to run a program to render a sphere, the sphere() command hangs and no window appears.
>

> <Screen Shot 2019-04-02 at 11.06.17 AM.png>
>
> When I enter these same commands to a Jupyter Notebook (5.7.8) running in the same environment, it works, and the sphere is rendered.
>
> I'd appreciate any suggestions on how to fix this problem.
>
> Thanks,
> -John
>

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[John Burk]

Thanks so much. That fixed it. 

[Isabel Marie]

Hi, I am having the same issue, although I am using a virtual environment running python 3.7.2. I did the commend pip install vpython (installed v.7.5.0). John's program renders in a jupyter notebook (5.7.4) but the sphere() command hangs in jupyterlab (0.35.4). I ran the jupyter labextension install vpython but the issue is still present.

Any help would be appreciated.

Thanks,

Isabel

[John]

Here is the documentation for working with jupyter labextensions.

https://jupyterlab.readthedocs.io/en/stable/user/extensions.html

Check that the vpython labextension was installed correctly with the command

jupyter labextension list

You can try uninstalling and installing it.

jupyter labextension uninstall vpython

jupyter labextension install vpython

Also according to the labextension documentation "In order to install JupyterLab extensions, you need to have Node.js installed."  

You can also try looking at the javascript console in the jupyterlab notebook and see if there are any error messages being generated.

John

[Bruce Sherwood]

John, is it still advisable when using Anaconda to use "conda install -c vpython vpython" instead of using pip? Would that make any difference?

Bruce

[John]

Bruce, I don't think it would make any difference. It was mentioned that vpython was working fine in the jupyter notebook. The vpython labextension is installed from the npm website and is not part of vpython package on conda or pip.

John

[Bruce Sherwood]

Ah. Understood. So now the installation instructions at vpython. org includes this:

If you use Jupyter lab, after installing VPython you need to install Node.js (https://nodejs.org/en/download/) and then execute this:

    jupyter labextension install vpython

Bruce