Remove PropertyLayer and HasPropertyLayers mixin by codebreaker32 · Pull Request #3340 · mesa/mesa

codebreaker32 · 2026-02-18T09:55:36Z

This PR removes PropertyLayer and HasPropertyLayers from discrete spaces

Replaces PropertyLayer with raw NumPy arrays stored directly on the grid as _property_layers: dict[str, np.ndarray]. Property access on cells is handled via native property closures attached to the dynamic GridCell class.

Changes:

create_property_layer(name, ...) - allocates and attaches a new array
add_property_layer(name, array) - attaches an existing array
remove_property_layer(name) - removes array and cell accessor
select_cells() removed - use numpy directly on property_layers
Visualization backends updated to match new APIs
Sugarscape and Termites examples updated

Example Usage

grid.create_property_layer("sugar", default_value=0.0)

# grid-level: full array
grid.sugar[:] = 0              
grid.sugar[grid.sugar > 4] = 4 # numpy ops directly

 # cell-level: scalar
cell.sugar = 2.0              

# replaces select_cells type ops
coords = list(zip(*np.where(grid.sugar > 2)))

github-actions · 2026-02-18T10:11:49Z

Performance benchmarks:

Model	Size	Init time [95% CI]	Run time [95% CI]
BoltzmannWealth	small	🔵 -1.7% [-2.1%, -1.4%]	🔵 -0.4% [-0.9%, +0.1%]
BoltzmannWealth	large	🔵 -0.5% [-0.8%, -0.2%]	🔵 +1.5% [+1.2%, +1.9%]
Schelling	small	🔵 -0.8% [-1.1%, -0.6%]	🔵 +0.4% [+0.3%, +0.5%]
Schelling	large	🔵 -3.5% [-4.6%, -2.5%]	🟢 -8.6% [-13.0%, -5.2%]
WolfSheep	small	🔵 -2.7% [-3.1%, -2.4%]	🔵 -0.2% [-0.5%, +0.1%]
WolfSheep	large	🔵 +3.1% [+1.2%, +5.4%]	🔴 +8.1% [+4.6%, +11.4%]
BoidFlockers	small	🔵 +0.9% [+0.5%, +1.2%]	🔵 +2.4% [+2.1%, +2.6%]
BoidFlockers	large	🔵 +1.0% [+0.4%, +1.5%]	🔵 +2.6% [+2.4%, +2.7%]

codebreaker32 · 2026-02-18T10:53:01Z

Hi @quaquel
The PropertyLayer is deeply embedded in Visualisation as well, so I would love to get a heads up before working on it further if it aligns with your vision. I realize the diff is fairly large, but the core changes are concentrated in grid.py only

quaquel · 2026-02-18T11:07:08Z

I'll try to take a look somewhere today.

mesa/discrete_space/grid.py

mesa/examples/advanced/sugarscape_g1mt/model.py

quaquel

I like the direction this is taking. I have some initial thoughts and comments.

Also, separate from this, I still want to add sugarscape to the benchmarks.

github-actions · 2026-02-20T09:54:57Z

Performance benchmarks:

Model	Size	Init time [95% CI]	Run time [95% CI]
BoltzmannWealth	small	🔵 -1.8% [-2.3%, -1.3%]	🔵 +0.4% [+0.2%, +0.6%]
BoltzmannWealth	large	🔵 -0.9% [-1.4%, -0.4%]	🔵 +0.8% [-0.3%, +2.1%]
Schelling	small	🔵 -1.4% [-1.6%, -1.2%]	🔵 -0.8% [-0.9%, -0.6%]
Schelling	large	🔵 -0.9% [-1.3%, -0.6%]	🔵 +0.5% [-0.3%, +1.9%]
WolfSheep	small	🔵 -0.3% [-0.6%, -0.1%]	🔵 -0.2% [-0.3%, +0.0%]
WolfSheep	large	🔵 -0.2% [-1.2%, +0.9%]	🔵 +0.3% [-1.6%, +1.9%]
BoidFlockers	small	🔵 -0.2% [-0.6%, +0.2%]	🔵 -1.9% [-2.1%, -1.8%]
BoidFlockers	large	🔵 -0.1% [-0.5%, +0.3%]	🔵 -1.2% [-1.6%, -0.8%]

codebreaker32 · 2026-02-21T05:48:40Z

This PR is ready for review.

During refactoring, I noticed that using property feels a bit awkward since it’s also a built-in Python decorator. Should we consider a clearer alternative name?

codebreaker32 · 2026-02-21T17:03:00Z

I profiled the Sugarscape model comparing main against this PR and results are:

Run	main	This PR	Change(in %)
Run 1	3.81	3.69	96.90%
Run 2	3.97	3.56	89.89%
Run 3	3.25	3.08	94.50%
Run 4	3.39	3.14	92.82%
Run 5	3.44	3.16	91.67%
Run 6	3.43	3.49	101.64%
Run 7	3.23	3.15	97.58%
Run 8	3.05	3.02	98.93%
Run 9	3.50	3.62	103.60%
Run 10	3.91	3.52	90.03%

1000 steps in each Run with different rng

codebreaker32 · 2026-02-21T17:12:34Z

On termites model from mesa-examples

Run	main	This PR	Change (%)
Run 1	6.90	6.93	100.39%
Run 2	6.72	7.36	109.63%
Run 3	6.33	7.06	111.46%
Run 4	7.01	6.49	92.64%
Run 5	6.57	7.30	111.23%
Run 6	6.49	6.21	95.63%
Run 7	6.56	6.78	103.34%
Run 8	6.25	6.59	105.54%
Run 9	6.57	6.85	104.18%
Run 10	6.37	6.37	100.06%

1000 steps in each run with different rng

quaquel · 2026-02-22T12:50:27Z

Can you take a look at the pre-commit and fix the errors?

mesa/discrete_space/discrete_space.py

mesa/discrete_space/grid.py

codebreaker32 · 2026-02-22T15:03:19Z

In some methods/arguments naming, we were using propertylayer*( such as for propertylayer_portrayal) and somewhere else property_layer*. While renaming back, I was finding it difficult to sync where we have used what so I have replaced all propertylayer* namings with property_layer* to maintain uniformity

codebreaker32 · 2026-02-22T15:08:15Z

docs/tutorials/9_visualization_propertylayer_visualization.ipynb

-    "> **NOTE:**\n",
-    "> This is not a tutorial on property layers themselves, but rather on their visualization. To explore the functionalities of property layers, please refer to this tutorial.\n",


I removed this Note because I couldn't find any tuorial link here.

codebreaker32 · 2026-02-22T15:12:04Z

I think this is good to go from my end. I have also opened a PR in mesa-examples for failing example mesa/mesa-examples#334

mesa/examples/advanced/sugarscape_g1mt/model.py

quaquel

This looks largely fine. One remaining API level question.

mesa/discrete_space/grid.py

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mesa/examples/advanced/sugarscape_g1mt/model.py

Co-authored-by: Jan Kwakkel <[email protected]>

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Refactor sugar and spice updates in step function for clarity.

codebreaker32 marked this pull request as draft February 18, 2026 09:56

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Remove PropertyLayer usage from mesa-examples mesa/mesa-examples#334

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codebreaker32 changed the title ~~Remove PropertyLayer~~ Remove PropertyLayer and HasPropertyLayers mixin Feb 22, 2026

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Stacked Spaces Registration API Design #3377

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This was referenced Mar 4, 2026

Delete property_layer.py #3432

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Using PropertyLayer instead of stationary patch agents in some examples mesa/mesa-examples#366

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Mesa 4 development tracking issue #3132

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		"> NOTE:\n",
		"> This is not a tutorial on property layers themselves, but rather on their visualization. To explore the functionalities of property layers, please refer to this tutorial.\n",

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