Remove unique_id and model.next_id (#194)

All examples can be updated to no longer pass a unique id, nor use model.next_id.

This only fixes the examples, not the gis-examples or rl examples.

Co-authored-by: Ewout ter Hoeven <[email protected]>

Author: quaquel

examples/basic/boid_flockers/boid_flockers/model.py

@@ -26,7 +26,6 @@ class Boid(mesa.Agent):
 
     def __init__(
         self,
-        unique_id,
         model,
         speed,
         direction,
@@ -40,7 +39,6 @@ def __init__(
         Create a new Boid flocker agent.
 
         Args:
-            unique_id: Unique agent identifier.
             speed: Distance to move per step.
             direction: numpy vector for the Boid's direction of movement.
             vision: Radius to look around for nearby Boids.
@@ -49,7 +47,7 @@ def __init__(
             separate: the relative importance of avoiding close neighbors
             match: the relative importance of matching neighbors' headings
         """
-        super().__init__(unique_id, model)
+        super().__init__(model)
         self.speed = speed
         self.direction = direction
         self.vision = vision
@@ -129,13 +127,12 @@ def make_agents(self):
         """
         Create self.population agents, with random positions and starting headings.
         """
-        for i in range(self.population):
+        for _ in range(self.population):
             x = self.random.random() * self.space.x_max
             y = self.random.random() * self.space.y_max
             pos = np.array((x, y))
             direction = np.random.random(2) * 2 - 1
             boid = Boid(
-                unique_id=i,
                 model=self,
                 speed=self.speed,
                 direction=direction,

examples/basic/boltzmann_wealth_model/boltzmann_wealth_model/model.py

@@ -26,8 +26,8 @@ def __init__(self, N=100, width=10, height=10):
             model_reporters={"Gini": compute_gini}, agent_reporters={"Wealth": "wealth"}
         )
         # Create agents
-        for i in range(self.num_agents):
-            a = MoneyAgent(i, self)
+        for _ in range(self.num_agents):
+            a = MoneyAgent(self)
 
             # Add the agent to a random grid cell
             x = self.random.randrange(self.grid.width)
@@ -50,8 +50,8 @@ def run_model(self, n):
 class MoneyAgent(mesa.Agent):
     """An agent with fixed initial wealth."""
 
-    def __init__(self, unique_id, model):
-        super().__init__(unique_id, model)
+    def __init__(self, model):
+        super().__init__(model)
         self.wealth = 1
 
     def move(self):

examples/basic/conways_game_of_life/conways_game_of_life/cell.py

@@ -11,7 +11,7 @@ def __init__(self, pos, model, init_state=DEAD):
         """
         Create a cell, in the given state, at the given x, y position.
         """
-        super().__init__(pos, model)
+        super().__init__(model)
         self.x, self.y = pos
         self.state = init_state
         self._nextState = None

examples/basic/schelling/model.py

@@ -6,16 +6,15 @@ class SchellingAgent(mesa.Agent):
     Schelling segregation agent
     """
 
-    def __init__(self, unique_id, model, agent_type):
+    def __init__(self, model, agent_type):
         """
         Create a new Schelling agent.
 
         Args:
-           unique_id: Unique identifier for the agent.
            x, y: Agent initial location.
            agent_type: Indicator for the agent's type (minority=1, majority=0)
         """
-        super().__init__(unique_id, model)
+        super().__init__(model)
         self.type = agent_type
 
     def step(self):
@@ -82,7 +81,7 @@ def __init__(
         for _, pos in self.grid.coord_iter():
             if self.random.random() < self.density:
                 agent_type = 1 if self.random.random() < self.minority_pc else 0
-                agent = SchellingAgent(self.next_id(), self, agent_type)
+                agent = SchellingAgent(self, agent_type)
                 self.grid.place_agent(agent, pos)
 
         self.datacollector.collect(self)

examples/basic/virus_on_network/virus_on_network/model.py

@@ -65,9 +65,8 @@ def __init__(
         )
 
         # Create agents
-        for i, node in enumerate(self.G.nodes()):
+        for node in self.G.nodes():
             a = VirusAgent(
-                i,
                 self,
                 State.SUSCEPTIBLE,
                 self.virus_spread_chance,
@@ -112,15 +111,14 @@ class VirusAgent(mesa.Agent):
 
     def __init__(
         self,
-        unique_id,
         model,
         initial_state,
         virus_spread_chance,
         virus_check_frequency,
         recovery_chance,
         gain_resistance_chance,
     ):
-        super().__init__(unique_id, model)
+        super().__init__(model)
 
         self.state = initial_state