Improve elastic-tube-1d code and documentation

[IshaanDesai]

Related to #188 but in the context of the new tutorials structure. The elastic-tube-1d was ported to the tutorials from a separate repository and this PR is a check if all the post-processing steps work as expected.

Closes #188

[IshaanDesai]

Attempting to generate a video in FluidSolver.py by passing the flag --write-video leads to the following error:

MovieWriter stderr:
convert-im6.q16: delegate failed `'ffmpeg' -nostdin -v -1 -i '%M%%d.jpg' '%u.%m' 2> '%u'' @ error/delegate.c/InvokeDelegate/1928.

Traceback (most recent call last):
  File "./FluidSolver.py", line 161, in <module>
    writer.finish()
  File "/home/desaiin/.local/lib/python3.8/site-packages/matplotlib/animation.py", line 354, in finish
    self.cleanup()
  File "/home/desaiin/.local/lib/python3.8/site-packages/matplotlib/animation.py", line 390, in cleanup
    raise subprocess.CalledProcessError(
subprocess.CalledProcessError: Command '['convert', '-size', '640x480', '-depth', '8', '-delay', '6.666666666666667', '-loop', '0', 'rgba:-', 'writer_test.mp4']' returned non-zero exit status 1.
(0) 10:32:47 [impl::SolverInterfaceImpl]:147 in ~SolverInterfaceImpl: Implicitly finalizing in destructor

@MakisH could you please reproduce this to ensure it is not just something with my system? If this persists then I suggest temporarily suspending the video writing functionality and resolving this in another PR. This PR already has a lot of clean-up

[MakisH]

python3 FluidSolver.py --enable-plot --write-video

works for me, I see the live animation. We should document this option.

I am using Python 3.8.6 and the Python binding v2.2.0.2.

[IshaanDesai]

I see the live animation

I also see the live animation which is the succession of plots generated by matplotlib. But do you get a valid .mp4 file in the directory at the end of the simulation? I see this error at the very end.

[MakisH]

I get a valid video file, here it is:

writer_test.mp4

I don't see any errors even after completing (fluid-python + solid-python).

Edit: GitHub does not show the video, but it works with every player I tried locally (GNOME Videos, VLC). Renaming it to something more decsriptive than writer_test.mp4 would be good, though.

video.tar.gz

[IshaanDesai]

I get a valid video file

Okay great, in that case I add the --write-video flag information to the README and this PR is ready to be merged.

[MakisH]

Maybe already try fixing the failing "Lint docs" pipeline to experience these new checks, it should be very easy. :-)

[IshaanDesai]

Maybe already try fixing the failing "Lint docs" pipeline to experience these new checks, it should be very easy. :-)

Interestingly doing act -j check_md passes on my local machine but somehow fails in the remote deployment! Have you experienced this before?

[MakisH]

Interestingly doing act -j check_md passes on my local machine but somehow fails in the remote deployment! Have you experienced this before?

I have not yet had the chance to try out act, so no clue here. But I use the davidanson.vscode-markdownlint extension in VSCode and it shows the same errors (since all exceptions are already in the files or in the project markdownlint config.

[IshaanDesai]

I have not yet had the chance to try out act, so no clue here. But I use the davidanson.vscode-markdownlint extension in VSCode and it shows the same errors (since all exceptions are already in the files or in the project markdownlint config.

Thanks! davidanson.vscode-markdownlint extension caught the problem even though act -j check_md did not catch it.