A mixed bag of python questions: Ipython crash, best build-backend, matplotlib inline plotting, pytorch

[allanolesen]

I discovered a-shell yesterday and am now trying to figure out how far I can get with a-shell as a python development platform for my own private python packages. Until now, I have used a mixture of GitHub Codespaces and Carnets Plus, but Codespaces isn't local on my iPad, and Carnets Plus seems limited to notebooks only.

So far I have stumbled into the following questions/issues.

Ipython crash
If I start ipython with python3 -m IPython, everything works fine. However, if I start it with ipython, it works only once. The next two starts will crash. Then it will work again once. Crash twice, etc.

Is this a known issue?

If yes: Is the cause and potential fixes already well-understood?
I ask this cryptical question, because my prosthetic brain proposed some possible fixes to a-shell after driving me through a lot of testing to isolate the problem. However, I don't trust LLMs, and I don't want to waste everyone's time by posting the results here.

Anyway, the overly confident answer from the LLM was that ipython is crashing because it is trying to get a ctypes handle to a-shell's python implementation, and this handle is missing or bad. I have a long report from that session, and I will be happy to share it with anyone who is willing to potentially waste their time reading it.

Inline plotting with mathplotlib
I do not really expect to be able to plot inline in a terminal. But I will ask anyway, hoping that a solution exists. It would be nice tosomehow see the plots without changing all my code so it saves them as files.

Build backend for my own packages
Is there a "whitelist" of build backends, which behave well in a-shell when pip builds a package from source on the fly, using the build backend information in that package's pyproject.toml?

I tried one of my packages, which had poetry as its build backend, and that caused pip to fail with the message 'pip._vendor.pyproject_hooks._impl.BackendUnavailable: Cannot import 'poetry.core.masonry.api''.

Is it possible to install pytorch?
I already know why the answer has to be 'no'. I am asking anyway, just to be sure.

Integration between a-shell and Carnets Plus?
Is it correctly understood that Carnets Plus can only run python code as .ipynb files? I can edit .py files, but I have not found a way to execute them.

When I have both a-shell and Carnets Plus installed, is there some way of combining their functionality into something resembling an IDE for python code?

[holzschu]

Hi,
thanks for the kind words. I'm going to try to answer your questions:

• ipython crashing: it was raised a few days ago on our Discord channel: https://discord.com/channels/935519150305050644/1107396954767503480/threads/1448684596207026350 I haven't yet started to work on it.
• LLM and a-Shell: LLMs base their answers on an existing corpus of text that they gathered on the web. Since a-Shell is not well known, there are very few pages about it, and so LLM answers are almost always wrong.
• inline plotting with matplotlib: I vaguely remember that there is a command to display images in the terminal (imgcat ?) and a matplotlib backend to take advantage of that.
• Python packages: only pure Python packages can be installed with a-Shell. There are no ways to generate a binary on the iPad that can be loaded afterwards. Same with installing pytorch yourself (but it's one of the packages I am planning to add).
• a-Shell and Carnets plus: they are separate apps. Each of them can access the directories of the other (using pickFolder on a-Shell, navigating with Carnets) but that won't help a lot: ipynb files are not designed for editing outside of a Jupyter editor. You can run Python files inside Jupyter with exec(open("filename.py").read()), of course.

[allanolesen]

Hm. I think I actually forgot the kind words. So I will add them now:

I have owned this ipad with a magic keyboard for 3 years. I have always been disappointed that it lacked 3 things I can't live without:

• a free git client with push capability
  • (I have the free version of Working Copy, and I would probably had upgraded to the pay version if this was my only missing piece of the puzzle.)
• a CLI
• a way to run .py files locally
  • (I used your Carnets Plus, and I have been very happy to have it, but Notebooks are sort of a niche use case for me.)

Yesterday I decided to see if the git situation had improved, and I saw someone mention a-shell, so I downloaded it. And found out that not only does it check all three boxes and not just the one box I was looking for - it has also been available to me the entire time, right under my nose, from the author of Carnets Plus!

This is fucking awesome, and I mean it sincerely. Do you take donations? I have looked both here on Github and on your website, but didn't see any options of donating.

[allanolesen]

By the way, it surprises me that you are thinking of including pytorch. Isn't it far too large to be included? When I installed pytorch in a virtual environment on my Github Codespaces desktop, the size of the venv folder increased by 5 or 6 GB.

If pytorch get included, will it be able to use GPU hardware acceleration from Apple's Metal Performance Shaders (like pytorch using CUDA on a PC with an Nvidia GPU)? Or will it be a CPU-only version?

[holzschu]

Regarding PyTorch, it's one of the most frequently requested packages. I have several goals:

1. cross-compile it and make it work,
2. have a look at how much it increases the size of the app. I'll see about making a release based on those facts.

It would probably be a CPU-only version, the code for the Metal shaders seems to be Mac-specific. At least at first.