Need to create and update figures in seperate cells?

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Stale
Tech stack
jupyter, jupyter-notebook, python

Research direction

The issue names no repository files or tests. Start by reproducing the separate-cell and combined-cell examples in JupyterLab, then compare how the long-running update_function affects rendering. Done means the combined cell updates the figure as requested, or the issue documents a confirmed limitation and its correct workaround.

Written by the indexing model from the issue text.

Description

Something I've seen in previous versions as well as the current version: In order to have a figure that dynamically updates while some code is executing (e.g. tracking the loss function of an optimization), I have to create the figure in a separate jupyter notebook cell and run it before a I run the code that updates. If I don't do this, then a blank figure shows and never updates. I'm using Jupyter lab. Wondering if I'm doing something wrong here? It would make the code cleaner and easier to run if it could all be put in a single cell.

Example:

Using the following function:

def update_function(fig, ax):
   while True:
       # Do some computation
       ax.clear() #clear previously drawn
       ax.plot(some_data)
       fig.canvas.draw() #force it to update

This works:

# cell 1
fig, ax = plt.subplots()
# cell 2
update_function(fig, ax)

But this does not:

# one combined cell
fig, ax = plt.subplots()
update_function(fig, ax)
Dominant language
Jupyter Notebook
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Forks
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