Bugfix for Solara deepcopy bug

mesa/examples/basic/boltzmann_wealth_model/app.py

@@ -20,6 +20,11 @@
         "max": 100,
         "step": 1,
     },
+    "seed": {
+        "type": "InputText",
+        "value": 42,
+        "label": "Random Seed",
+    },
     "width": 10,
     "height": 10,
 }
@@ -30,7 +35,7 @@
 
 
 # Create initial model instance
-model1 = BoltzmannWealthModel(50, 10, 10)
+model = BoltzmannWealthModel(50, 10, 10)
 
 # Create visualization elements. The visualization elements are solara components
 # that receive the model instance as a "prop" and display it in a certain way.
@@ -49,7 +54,7 @@
 # solara run app.py
 # It will automatically update and display any changes made to this file
 page = SolaraViz(
-    model1,
+    model,
     components=[SpaceGraph, GiniPlot],
     model_params=model_params,
     name="Boltzmann Wealth Model",

mesa/visualization/solara_viz.py

@@ -24,7 +24,6 @@
 from __future__ import annotations
 
 import asyncio
-import copy
 import inspect
 from collections.abc import Callable
 from typing import TYPE_CHECKING, Literal
@@ -48,7 +47,6 @@ def SolaraViz(
     | Literal["default"] = "default",
     play_interval: int = 100,
     model_params=None,
-    seed: float = 0,
     name: str | None = None,
 ):
     """Solara visualization component.
@@ -69,8 +67,6 @@ def SolaraViz(
             This controls the speed of the model's automatic stepping. Defaults to 100 ms.
         model_params (dict, optional): Parameters for (re-)instantiating a model.
             Can include user-adjustable parameters and fixed parameters. Defaults to None.
-        seed (int, optional): Seed for the random number generator. This ensures reproducibility
-            of the model's behavior. Defaults to 0.
         name (str | None, optional): Name of the visualization. Defaults to the models class name.
 
     Returns:
@@ -88,7 +84,9 @@ def SolaraViz(
           value results in faster stepping, while a higher value results in slower stepping.
     """
     if components == "default":
-        components = [components_altair.make_space_altair()]
+        components = [components_altair.make_altair_space()]
+    if model_params is None:
+        model_params = {}
 
     # Convert model to reactive
     if not isinstance(model, solara.Reactive):
@@ -109,20 +107,23 @@ def step():
 
     solara.use_effect(connect_to_model, [model.value])
 
+    # set up reactive model_parameters shared by ModelCreator and ModelController
+    reactive_model_parameters = solara.use_reactive({})
+
     with solara.AppBar():
         solara.AppBarTitle(name if name else model.value.__class__.__name__)
 
     with solara.Sidebar(), solara.Column():
         with solara.Card("Controls"):
-            ModelController(model, play_interval)
-
-        if model_params is not None:
-            with solara.Card("Model Parameters"):
-                ModelCreator(
-                    model,
-                    model_params,
-                    seed=seed,
-                )
+            ModelController(
+                model,
+                model_parameters=reactive_model_parameters,
+                play_interval=play_interval,
+            )
+        with solara.Card("Model Parameters"):
+            ModelCreator(
+                model, model_params, model_parameters=reactive_model_parameters
+            )
         with solara.Card("Information"):
             ShowSteps(model.value)
 
@@ -173,24 +174,23 @@ def ComponentsView(
 
 
 @solara.component
-def ModelController(model: solara.Reactive[Model], play_interval=100):
+def ModelController(
+    model: solara.Reactive[Model],
+    model_parameters: dict | solara.Reactive[dict] = None,
+    play_interval: int = 100,
+):
     """Create controls for model execution (step, play, pause, reset).
 
     Args:
-        model (solara.Reactive[Model]): Reactive model instance
-        play_interval (int, optional): Interval for playing the model steps in milliseconds.
+        model: Reactive model instance
+        model_parameters: Reactive parameters for (re-)instantiating a model.
+        play_interval: Interval for playing the model steps in milliseconds.
+
     """
     playing = solara.use_reactive(False)
     running = solara.use_reactive(True)
-    original_model = solara.use_reactive(None)
-
-    def save_initial_model():
-        """Save the initial model for comparison."""
-        original_model.set(copy.deepcopy(model.value))
-        playing.value = False
-        force_update()
-
-    solara.use_effect(save_initial_model, [model.value])
+    if model_parameters is None:
+        model_parameters = solara.use_reactive({})
 
     async def step():
         while playing.value and running.value:
@@ -210,7 +210,7 @@ def do_reset():
         """Reset the model to its initial state."""
         playing.value = False
         running.value = True
-        model.value = copy.deepcopy(original_model.value)
+        model.value = model.value = model.value.__class__(**model_parameters.value)
 
     def do_play_pause():
         """Toggle play/pause."""
@@ -269,17 +269,21 @@ def check_param_is_fixed(param):
 
 
 @solara.component
-def ModelCreator(model, model_params, seed=1):
+def ModelCreator(
+    model: solara.Reactive[Model],
+    user_params: dict,
+    model_parameters: dict | solara.Reactive[dict] = None,
+):
     """Solara component for creating and managing a model instance with user-defined parameters.
 
     This component allows users to create a model instance with specified parameters and seed.
     It provides an interface for adjusting model parameters and reseeding the model's random
     number generator.
 
     Args:
-        model (solara.Reactive[Model]): A reactive model instance. This is the main model to be created and managed.
-        model_params (dict): Dictionary of model parameters. This includes both user-adjustable parameters and fixed parameters.
-        seed (int, optional): Initial seed for the random number generator. Defaults to 1.
+        model: A reactive model instance. This is the main model to be created and managed.
+        user_params: Parameters for (re-)instantiating a model. Can include user-adjustable parameters and fixed parameters. Defaults to None.
+        model_parameters: reactive parameters for reinitializing the model
 
     Returns:
         solara.component: A Solara component that renders the model creation and management interface.
@@ -300,24 +304,25 @@ def ModelCreator(model, model_params, seed=1):
         - The component provides an interface for adjusting user-defined parameters and reseeding the model.
 
     """
+    if model_parameters is None:
+        model_parameters = solara.use_reactive({})
+
     solara.use_effect(
         lambda: _check_model_params(model.value.__class__.__init__, fixed_params),
         [model.value],
     )
+    user_params, fixed_params = split_model_params(user_params)
 
-    user_params, fixed_params = split_model_params(model_params)
-
-    model_parameters, set_model_parameters = solara.use_state(
-        {
-            **fixed_params,
-            **{k: v.get("value") for k, v in user_params.items()},
-        }
-    )
+    # set model_parameters to the default values for all parameters
+    model_parameters.value = {
+        **fixed_params,
+        **{k: v.get("value") for k, v in user_params.items()},
+    }
 
     def on_change(name, value):
-        new_model_parameters = {**model_parameters, name: value}
+        new_model_parameters = {**model_parameters.value, name: value}
         model.value = model.value.__class__(**new_model_parameters)
-        set_model_parameters(new_model_parameters)
+        model_parameters.value = new_model_parameters
 
     UserInputs(user_params, on_change=on_change)
 
@@ -409,6 +414,12 @@ def change_handler(value, name=name):
                 on_value=change_handler,
                 value=options.get("value"),
             )
+        elif input_type == "InputText":
+            solara.InputText(
+                label=label,
+                on_value=change_handler,
+                value=options.get("value"),
+            )
         else:
             raise ValueError(f"{input_type} is not a supported input type")
 

tests/test_solara_viz.py

@@ -101,7 +101,11 @@ def test_call_space_drawer(mocker):  # noqa: D103
         mesa.visualization.components.altair_components, "SpaceAltair"
     )
 
-    model = mesa.Model()
+    class MockModel(mesa.Model):
+        def __init__(self, seed=None):
+            super().__init__(seed=seed)
+
+    model = MockModel()
     mocker.patch.object(mesa.Model, "__init__", return_value=None)
 
     agent_portrayal = {
@@ -112,7 +116,10 @@ def test_call_space_drawer(mocker):  # noqa: D103
     # initialize with space drawer unspecified (use default)
     # component must be rendered for code to run
     solara.render(
-        SolaraViz(model, components=[make_mpl_space_component(agent_portrayal)])
+        SolaraViz(
+            model,
+            components=[make_mpl_space_component(agent_portrayal)],
+        )
     )
     # should call default method with class instance and agent portrayal
     mock_space_matplotlib.assert_called_with(