Releases · projectmesa/mesa

09 Sep 15:42

EwoutH

v3.0.0a4

eaf7457

v3.0 alpha 4 (pre-release) Pre-release

Pre-release

Highlights

Mesa 3.0.0a4 contains two major breaking changes:

The Agent's unique_id is now automatically assigned, so doesn't need to be passed to the Agent class anymore. In a subclassed custom Agent, like normally used, this now looks like this:

class Wolf(Agent):
-    def __init__(self, unique_id, model, energy=None):
+    def __init__(self, model, energy=None):
        # When initializing the super class (Agent), passing unique_id isn't needed anymore
-        super().__init__(unique_id, model)
+        super().__init__(model)

- wolf = Wolf(unique_id, model)
+ wolf = Wolf(model)

Example models were updated in mesa-examples#194, which shows more examples on how to update existing models.

Our visualisation API is being overhauled, to be more flexible and powerful. For more details, see #2278.
- An initial update to the tutorial was made in #2289 and is available here.
- An initial example model was updated in mesa-examples#195, and more examples will be updated in mesa-examples#195.
- The old SolaraViz API is still available at mesa.experimental, but might be removed in future releases.

Furthermore, the AgentSet has a new agg method to quickly get an aggerate value (for example min_energy = model.agents.agg("energy", min)) (#2266), The Model get_agents_of_type function is replaced by directly exposing the agents_by_type property (which can be accessed as a dict) (#2267, mesa-examples#190) and the AgentSet get() methods can now handle missing values by replacing it with a default value (#2279).

Finally, it fixes a bug in which the Grid's move_agent_to_one_of method with selection="closest" selected a location deterministically, instead of randomly (#2118).

What's Changed

⚠️ Breaking changes

move solara_viz back to experimental by @Corvince in #2278
track unique_id automatically by @quaquel in #2260

🎉 New features added

AgentSet: Add agg method by @EwoutH in #2266
Implement new SolaraViz API by @Corvince in #2263

🛠 Enhancements made

Model: Replace get_agents_of_type method with agents_by_type property by @EwoutH in #2267
add default SolaraViz by @Corvince in #2280
Simplify ModelController by @Corvince in #2282
Add default values and missing value handling to agentset.get by @quaquel in #2279

🐛 Bugs fixed

Fix deterministic behavior in move_agent_to_one_of with selection="closest" by @OrenBochman in #2118

📜 Documentation improvements

docs: Fix Visualization Tutorial (main branch) by @EwoutH in #2271
Docs: Fix broken relative links by removing .html suffix by @EwoutH in #2274
Readthedocs: Don't let notebook failures pass silently by @EwoutH in #2276
Update viz tutorial to the new API by @Corvince in #2289

🔧 Maintenance

Resolve multiprocessing warning, state Python 3.13 support by @rht in #2246

New Contributors

@OrenBochman made their first contribution in #2118

Full Changelog: v3.0.0a3...v3.0.0a4

Contributors

rht, OrenBochman, and 3 other contributors

Assets 2

04 Sep 09:12

EwoutH

v2.3.4

8daebf5

v2.3.4 Latest

Latest

Highlights

Two fixes in our docs: The visualization tutorial started using an example model that wasn't compatible with Mesa 2.x anymore, and some relative links were broken. This release fixes both.

What's Changed

📜 Documentation improvements

docs: Fix Visualization Tutorial (2.x branch) by @EwoutH in #2272
Docs: Fix broken relative links by removing .html suffix by @EwoutH in #2274

Full Changelog: v2.3.3...v2.3.4

Contributors

EwoutH

Assets 2

01 Sep 11:56

EwoutH

v2.3.3

3583293

v2.3.3

Highlights

Mesa v2.3.3 is a small patch release with documentation and maintenance updates backported from our main branch.

We do have included one feature as preview for Mesa 3.0: The AgentSet got a convenient set method to quickly set a variable value to (a subset of) agents. See #2254 for some examples.

What's Changed

🎉 New features added

AgentSet: Add set method by @EwoutH in #2254

📜 Documentation improvements

Fix image on landing page of docs. by @jackiekazil in #2146
Replace links in docs - google group to matrix. by @jackiekazil in #2148
Add experimental features to documentation as per #2122 by @stephenfmann in #2154
Update visualisation docs by @EwoutH in #2162
Add original conference paper link to docs by @ENUMERA8OR in #2160
docs/conf.py: Use modern intersphinx_mapping format by @EwoutH in #2206
Contribution: Add "I have no idea where to start" section by @EwoutH in #2258

Full Changelog: v2.3.2...v2.3.3

Contributors

jackiekazil, EwoutH, and 2 other contributors

Assets 2

30 Aug 16:10

EwoutH

v3.0.0a3

002d3f4

v3.0 alpha 3 (pre-release) Pre-release

Pre-release

Highlights

Developments toward Mesa 3.0 are steaming ahead, and our fourth alpha release is packed with features and updates - only 8 days after our third.

Mesa 3.0.0a3 contains one breaking change: We now automatically increase the steps counter by one at the beginning of each Model.steps() call. That means increasing steps by hand isn't necessary anymore.

The big new features is the experimental Voronoi grid that @vitorfrois implemented in #2084. It allows creating cells in a Voronoi layout as part of the experimental cell space. An example using it to model Cholera spread can be found here.

The AgentSet got a lot of love with two brand new methods: .groupby() to split in groups (#2220) and .set() to easily assign variables to all agents in that set (#2254). The select() method is improved by allowing to select at most a fraction of the agents (#2253), and we split the do() method in do() and map() to make a distinction between the return types (#2237).

Furthermore, we improved the performance of accessing Model.agents, squashed a bug in SolaraViz, started testing on Python 3.13 and added a new benchmark model.

Our example models also got more love: We removed the RandomActivation scheduler in 14 models and removed SimultaneousActivation in 3 models (examples#183). They now use the automatic step increase and AgentSet functionality. We started testing our GIS model in CI (examples#171) and resolved a lot of bugs in them (examples#172, help appreciated!).

Finally, we have two brand new examples: An Ant Colony Optimization model using an Ant System approach to the Traveling Salesman problem, a Mesa NetworkGrid, and a custom visualisation with SolaraViz (examples#157 by @zjost). The first example using the PropertyLayer was added, a very fast implementation of Conway's Game of Life (examples#182).

To help the transition to Mesa 3.0, we started writing a migration guide. Progress is tracked in #2233, feedback and help is appreciated! Finally, we also added a new section to our contributor guide to get new contributors up to speed.

This pre-release can be installed as always with pip install --pre mesa