refactor: Simplify Sugarscape resource agents

This combines the Sugar and Spice resources into 1 resource class.

Author: rht

examples/sugarscape_g1mt/sugarscape_g1mt/model.py

@@ -1,7 +1,7 @@
 import mesa
 import numpy as np
 
-from .resource_agents import Spice, Sugar
+from .resource_agents import Resource
 from .trader_agents import Trader
 
 
@@ -93,18 +93,11 @@ def __init__(
         agent_id = 0
         for _, (x, y) in self.grid.coord_iter():
             max_sugar = sugar_distribution[x, y]
-            if max_sugar > 0:
-                sugar = Sugar(agent_id, self, (x, y), max_sugar)
-                self.schedule.add(sugar)
-                self.grid.place_agent(sugar, (x, y))
-                agent_id += 1
-
             max_spice = spice_distribution[x, y]
-            if max_spice > 0:
-                spice = Spice(agent_id, self, (x, y), max_spice)
-                self.schedule.add(spice)
-                self.grid.place_agent(spice, (x, y))
-                agent_id += 1
+            resource = Resource(agent_id, self, (x, y), max_sugar, max_spice)
+            self.schedule.add(resource)
+            self.grid.place_agent(resource, (x, y))
+            agent_id += 1
 
         for i in range(self.initial_population):
             # get agent position
@@ -157,13 +150,9 @@ def step(self):
         Unique step function that does staged activation of sugar and spice
         and then randomly activates traders
         """
-        # step Sugar agents
-        for sugar in self.schedule.agents_by_type[Sugar].values():
-            sugar.step()
-
-        # step Spice agents
-        for spice in self.schedule.agents_by_type[Spice].values():
-            spice.step()
+        # step Resource agents
+        for resource in self.schedule.agents_by_type[Resource].values():
+            resource.step()
 
         # step trader agents
         # to account for agent death and removal we need a seperate data strcuture to

examples/sugarscape_g1mt/sugarscape_g1mt/resource_agents.py

@@ -1,43 +1,26 @@
 import mesa
 
 
-class Sugar(mesa.Agent):
+class Resource(mesa.Agent):
     """
-    Sugar:
-    - contains an amount of sugar
+    Resource:
+    - contains an amount of sugar and spice
     - grows 1 amount of sugar at each turn
-    """
-
-    def __init__(self, unique_id, model, pos, max_sugar):
-        super().__init__(unique_id, model)
-        self.pos = pos
-        self.amount = max_sugar
-        self.max_sugar = max_sugar
-
-    def step(self):
-        """
-        Sugar growth function, adds one unit of sugar each step until
-        max amount
-        """
-        self.amount = min([self.max_sugar, self.amount + 1])
-
-
-class Spice(mesa.Agent):
-    """
-    Spice:
-    - contains an amount of spice
     - grows 1 amount of spice at each turn
     """
 
-    def __init__(self, unique_id, model, pos, max_spice):
+    def __init__(self, unique_id, model, pos, max_sugar, max_spice):
         super().__init__(unique_id, model)
         self.pos = pos
-        self.amount = max_spice
+        self.sugar_amount = max_sugar
+        self.max_sugar = max_sugar
+        self.spice_amount = max_spice
         self.max_spice = max_spice
 
     def step(self):
         """
-        Spice growth function, adds one unit of spice each step until
+        Growth function, adds one unit of sugar and spice each step up to
         max amount
         """
-        self.amount = min([self.max_spice, self.amount + 1])
+        self.sugar_amount = min([self.max_sugar, self.sugar_amount + 1])
+        self.spice_amount = min([self.max_spice, self.spice_amount + 1])

examples/sugarscape_g1mt/sugarscape_g1mt/trader_agents.py

@@ -2,7 +2,7 @@
 
 import mesa
 
-from .resource_agents import Spice, Sugar
+from .resource_agents import Resource
 
 
 # Helper function
@@ -50,47 +50,12 @@ def __init__(
         self.prices = []
         self.trade_partners = []
 
-    def get_sugar(self, pos):
-        """
-        used in self.get_sugar_amount()
-        """
-
-        this_cell = self.model.grid.get_cell_list_contents(pos)
-        for agent in this_cell:
-            if type(agent) is Sugar:
-                return agent
-        return None
-
-    def get_sugar_amount(self, pos):
-        """
-        used in self.move() as part of self.calculate_welfare()
-        """
-
-        sugar_patch = self.get_sugar(pos)
-        if sugar_patch:
-            return sugar_patch.amount
-        return 0
-
-    def get_spice(self, pos):
-        """
-        used in self.get_spice_amount()
-        """
-
+    def get_resource(self, pos):
         this_cell = self.model.grid.get_cell_list_contents(pos)
         for agent in this_cell:
-            if type(agent) is Spice:
+            if type(agent) is Resource:
                 return agent
-        return None
-
-    def get_spice_amount(self, pos):
-        """
-        used in self.move() as part of self.calculate_welfare()
-        """
-
-        spice_patch = self.get_spice(pos)
-        if spice_patch:
-            return spice_patch.amount
-        return 0
+        raise Exception(f"Resource agent not found in the position {pos}")
 
     def get_trader(self, pos):
         """
@@ -292,8 +257,8 @@ def move(self):
 
         welfares = [
             self.calculate_welfare(
-                self.sugar + self.get_sugar_amount(pos),
-                self.spice + self.get_spice_amount(pos),
+                self.sugar + self.get_resource(pos).sugar_amount,
+                self.spice + self.get_resource(pos).spice_amount,
             )
             for pos in neighbors
         ]
@@ -323,20 +288,15 @@ def move(self):
         self.model.grid.move_agent(self, final_candidate)
 
     def eat(self):
-        # get sugar
-        sugar_patch = self.get_sugar(self.pos)
-
-        if sugar_patch:
-            self.sugar += sugar_patch.amount
-            sugar_patch.amount = 0
+        patch = self.get_resource(self.pos)
+        if patch.sugar_amount > 0:
+            self.sugar += patch.sugar_amount
+            patch.sugar_amount = 0
         self.sugar -= self.metabolism_sugar
 
-        # get_spice
-        spice_patch = self.get_spice(self.pos)
-
-        if spice_patch:
-            self.spice += spice_patch.amount
-            spice_patch.amount = 0
+        if patch.spice_amount > 0:
+            self.spice += patch.spice_amount
+            patch.spice_amount = 0
         self.spice -= self.metabolism_spice
 
     def maybe_die(self):