Move boltzmann to cell spaces (#2680)

mesa/examples/basic/boltzmann_wealth_model/agents.py

@@ -1,7 +1,7 @@
-from mesa import Agent
+from mesa.discrete_space import CellAgent
 
 
-class MoneyAgent(Agent):
+class MoneyAgent(CellAgent):
     """An agent with fixed initial wealth.
 
     Each agent starts with 1 unit of wealth and can give 1 unit to other agents
@@ -11,28 +11,23 @@ class MoneyAgent(Agent):
         wealth (int): The agent's current wealth (starts at 1)
     """
 
-    def __init__(self, model):
+    def __init__(self, model, cell):
         """Create a new agent.
 
         Args:
             model (Model): The model instance that contains the agent
         """
         super().__init__(model)
+        self.cell = cell
         self.wealth = 1
 
     def move(self):
         """Move the agent to a random neighboring cell."""
-        possible_steps = self.model.grid.get_neighborhood(
-            self.pos, moore=True, include_center=False
-        )
-        new_position = self.random.choice(possible_steps)
-        self.model.grid.move_agent(self, new_position)
+        self.cell = self.cell.neighborhood.select_random_cell()
 
     def give_money(self):
         """Give 1 unit of wealth to a random agent in the same cell."""
-        cellmates = self.model.grid.get_cell_list_contents([self.pos])
-        # Remove self from potential recipients
-        cellmates.pop(cellmates.index(self))
+        cellmates = [a for a in self.cell.agents if a is not self]
 
         if cellmates:  # Only give money if there are other agents present
             other = self.random.choice(cellmates)

mesa/examples/basic/boltzmann_wealth_model/model.py

@@ -9,8 +9,8 @@
 
 from mesa import Model
 from mesa.datacollection import DataCollector
+from mesa.discrete_space import OrthogonalMooreGrid
 from mesa.examples.basic.boltzmann_wealth_model.agents import MoneyAgent
-from mesa.space import MultiGrid
 
 
 class BoltzmannWealth(Model):
@@ -39,22 +39,18 @@ def __init__(self, n=100, width=10, height=10, seed=None):
         super().__init__(seed=seed)
 
         self.num_agents = n
-        self.grid = MultiGrid(width, height, torus=True)
+        self.grid = OrthogonalMooreGrid((width, height), random=self.random)
 
         # Set up data collection
         self.datacollector = DataCollector(
             model_reporters={"Gini": self.compute_gini},
             agent_reporters={"Wealth": "wealth"},
         )
-
-        # Create and place the agents
-        for _ in range(self.num_agents):
-            agent = MoneyAgent(self)
-
-            # Add agent to random grid cell
-            x = self.random.randrange(self.grid.width)
-            y = self.random.randrange(self.grid.height)
-            self.grid.place_agent(agent, (x, y))
+        MoneyAgent.create_agents(
+            self,
+            self.num_agents,
+            self.random.choices(self.grid.all_cells.cells, k=self.num_agents),
+        )
 
         self.running = True
         self.datacollector.collect(self)