viz: stop running and disable buttons when model.running is False

[wang-boyu]

This PR stops calling model.step() from the frontend when model.running is False. Play and step buttons are also disabled.

[github-actions]

Performance benchmarks:

Model	Size	Init time [95% CI]	Run time [95% CI]
BoltzmannWealth	small	🔵 -1.4% [-2.2%, -0.5%]	🔵 -0.3% [-0.5%, -0.1%]
BoltzmannWealth	large	🔵 -0.5% [-0.8%, -0.1%]	🔵 -0.0% [-0.6%, +0.6%]
Schelling	small	🔵 -0.3% [-0.6%, +0.1%]	🔵 -0.0% [-0.3%, +0.2%]
Schelling	large	🔵 -0.3% [-0.7%, +0.1%]	🔵 -0.3% [-0.9%, +0.2%]
WolfSheep	small	🔵 +1.7% [+1.5%, +1.9%]	🔵 +1.3% [+1.1%, +1.4%]
WolfSheep	large	🔵 +1.7% [+1.1%, +2.3%]	🔵 +1.0% [+0.5%, +1.6%]
BoidFlockers	small	🔵 +0.6% [+0.1%, +1.2%]	🔵 -0.1% [-0.8%, +0.5%]
BoidFlockers	large	🔵 +1.2% [+0.3%, +1.9%]	🔵 -0.4% [-0.9%, +0.1%]

[Corvince]

Looks good to me!

[EwoutH]

How/when should/can I use this?

[wang-boyu]

Oh sorry I should've provided more context.

The current solara viz keeps calling model.step() and updating plots, even when the model stops itself, in models such as the Schelling example:

def step(self):
    # model logic
    ...
    if self.happy == len(self.agents):
        self.running = False

This PR stops the frontend when model.running becomes False, and disables the play and step buttons.

[EwoutH]

Awesome, sounds like an useful feature!

[EwoutH]

@quaquel want do you think about the whole self.running concept?

[quaquel]

@quaquel want do you think about the whole self.running concept?

A currently underdeveloped feature that needs to be implemented better. It is used with self.run_model, which is also strange and creates a typing mess. I. have looked at it a few times without coming up with a clean solution. My rough idea is to have some stopping_condition callable, which can be parameterized by arguments to self.run_model, and when the stopping condition becomes true, self.running is automatically set to false. By default this stopping_condition might simply be tied to steps and be parameterized with n for the number of steps. If this stopping_condition is a method on Model, you would have a meaningful default while making it user-extendable,

[rht]

Minor question:

I forgot about the old behavior of SolaraViz. Which one is it:
1.has it been this way but changed in #2299, then this PR fixes it
2. the bug has always been there even before #2299

This only affects whether it should be communicated as a bug fix or a new feature in the release note.

[wang-boyu]

It's probably included in #2263? I didn't try it but there were some usages of model.value.running. It was replaced with playing.value in #2282.

[wang-boyu]

Merged! Pls feel free to change the label if anyone thinks there's a better one.

[rht]

It's a bug fix. The old JupyterViz does check the model.running:

mesa/mesa/experimental/jupyter_viz.py

Lines 231 to 234 in 7addec3

	def do_play():
	model.running = True
	while model.running:
	do_step()

.