Update README and align parameter naming in app/model

Author: nyksans

examples/energy_expenditure/app.py

@@ -20,7 +20,7 @@ def agent_portrayal(agent):
 
 # Allow easy parameter tweaking
 model = EnergyModel(
-    N=20,
+    n=20,
     width=10,
     height=10,
 )

examples/energy_expenditure/model.py

@@ -1,112 +1,70 @@
 from mesa import Agent, Model
 from mesa.space import MultiGrid
-from mesa.time import RandomActivation
 
 
 class EnergyAgent(Agent):
-    """
-    Energy-based agent with a well-defined lifecycle.
-
-    Design guarantees:
-    - Energy is updated ONLY in step()
-    - Actions (move/rest) do not mutate energy
-    - Energy strictly decreases over time
-    - Agent is removed immediately when energy reaches zero
-
-    Invariant:
-        energy > 0  <=>  agent.alive == True
-    """
-
     # --- Tunable Parameters ---
     LOW_ENERGY_THRESHOLD = 4
     MOVE_DECAY = 1.0
     REST_DECAY = 0.4
 
-    def __init__(self, unique_id, model, energy=10):
-        super().__init__(unique_id, model)
+    def __init__(self, model, energy=10):
+        super().__init__(model)
         self.energy = energy
         self.alive = True
 
     def step(self):
-        """Single authoritative lifecycle step."""
-
         if not self.alive:
-            return  # safety guard
+            return
 
-        # --- Decision Phase ---
         is_resting = self.energy < self.LOW_ENERGY_THRESHOLD
 
-        # --- Action Phase (pure, no energy mutation) ---
         if is_resting:
             self.rest()
             decay = self.REST_DECAY
         else:
             self.move()
             decay = self.MOVE_DECAY
 
-        # --- Energy Update ---
         self.energy = max(self.energy - decay, 0)
 
-        # --- Immediate Death (no zombie tick) ---
         if self.energy == 0:
             self._die()
 
     def move(self):
-        """Move to a random neighboring cell."""
         neighbors = self.model.grid.get_neighborhood(
             self.pos, moore=True, include_center=False
         )
-
         if neighbors:
             new_pos = self.random.choice(neighbors)
             self.model.grid.move_agent(self, new_pos)
 
     def rest(self):
-        """Agent remains stationary to conserve energy."""
+        pass
 
     def _die(self):
-        """
-        Safe removal:
-        - Marks agent as dead
-        - Removes from grid and scheduler
-        """
         self.alive = False
         self.model.grid.remove_agent(self)
-        self.model.schedule.remove(self)
+        self.remove()  # deregisters from model AgentSet
 
 
 class EnergyModel(Model):
-    """
-    Model with agents that expend energy over time and eventually die.
-
-    Behavior:
-    - Agents move when energy is sufficient
-    - Agents rest when energy is low
-    - All agents eventually die due to energy depletion
-    """
-
     def __init__(self, n=10, width=10, height=10):
         super().__init__()
-
         self.num_agents = n
         self.grid = MultiGrid(width, height, torus=True)
-        self.schedule = RandomActivation(self)
-
-        # Create agents
-        for i in range(self.num_agents):
-            agent = EnergyAgent(i, self)
-            self.schedule.add(agent)
 
+        for _ in range(self.num_agents):
+            agent = EnergyAgent(self)
             x = self.random.randrange(self.grid.width)
             y = self.random.randrange(self.grid.height)
             self.grid.place_agent(agent, (x, y))
 
         self.running = True
 
     def step(self):
-        """Advance the model by one step."""
-        self.schedule.step()
+        # RandomActivation replacement in Mesa 3.x
+        self.agents.shuffle_do("step")
 
-        # Stop simulation if no agents remain
-        if self.schedule.get_agent_count() == 0:
+        if len(self.agents) == 0:
             self.running = False