Sugarscape Chapter 3- Draft Pull Request

examples/sugarscape_cg/sugarscape_cg/model.py

@@ -47,11 +47,9 @@ def __init__(self, width=50, height=50, initial_population=100):
         import numpy as np
 
         sugar_distribution = np.genfromtxt(Path(__file__).parent / "sugar-map.txt")
-        agent_id = 0
         for _, (x, y) in self.grid.coord_iter():
             max_sugar = sugar_distribution[x, y]
-            sugar = Sugar(agent_id, (x, y), self, max_sugar)
-            agent_id += 1
+            sugar = Sugar(self.next_id(), (x, y), self, max_sugar)
             self.grid.place_agent(sugar, (x, y))
             self.schedule.add(sugar)
 
@@ -62,8 +60,9 @@ def __init__(self, width=50, height=50, initial_population=100):
             sugar = self.random.randrange(6, 25)
             metabolism = self.random.randrange(2, 4)
             vision = self.random.randrange(1, 6)
-            ssa = SsAgent(agent_id, (x, y), self, False, sugar, metabolism, vision)
-            agent_id += 1
+            ssa = SsAgent(
+                self.next_id(), (x, y), self, False, sugar, metabolism, vision
+            )
             self.grid.place_agent(ssa, (x, y))
             self.schedule.add(ssa)
 

examples/sugarscape_scc/README.md

@@ -0,0 +1,43 @@
+# Sugarscape: Sex, Culture, and Conflict : The Emergence of History
+
+## Summary
+
+This is a work-in-progress implementation of Chapter 3 from *Growing Artificial Societies: Social Science from the Bottom Up.*, adding mechanics such as sexual reproduction, cultural exchange and combat.
+
+This model greatly increases the complexity of interactions between agents, following on from Chapter 2's model.
+
+## Mechanics Introduced
+
+### Sexual Reproduction
+
+We assign agents a trait, **Fertility**, according to which they can perform Agent Rule **S**:
+- Select a neighbour at random
+- If the neighbor is fertile and of the opposite sex and at least one of the agents has an empty neighboring site (for the baby), then a child is born
+- Repeat for all neighbors
+
+###  Cultural Processes (WIP)
+
+### Combat (WIP)
+
+This model demonstrates visualisation of agent attributes.
+## How to Run
+
+To run the model interactively, run ``mesa runserver`` in this directory. e.g.
+
+`$ mesa runserver`
+
+Then open your browser to [http://127.0.0.1:8521/](http://127.0.0.1:8521/) and press **Reset**, then **Run**.
+
+## Files
+
+* `sugarscape_scc/agents.py`: Adds chapter-specific mechanics to `sugarscape_cg/agent.py`
+* `sugarscape_scc/server.py`: Sets up the interactive server with charts visualising data.
+* `sugarscape_scc/model.py`: Defines the Sugarscape model itself
+* `run.py`: Launches a model visualization server.
+
+## Further Reading
+
+Epstein, J. M., & Axtell, R. (n.d.). *Growing Artificial Societies*: Social science from the bottom up. Brookings Institution Press, Chapter 3.
+
+
+The ant sprite is taken from https://openclipart.org/detail/229519/ant-silhouette, with CC0 1.0 license.

examples/sugarscape_scc/run.py

@@ -0,0 +1,3 @@
+from sugarscape_scc.server import server
+
+server.launch(open_browser=True)

examples/sugarscape_scc/sugarscape_scc/agents.py

@@ -0,0 +1,146 @@
+import math
+
+import mesa
+
+
+def get_distance(pos_1, pos_2):
+    """Get the distance between two point
+
+    Args:
+        pos_1, pos_2: Coordinate tuples for both points.
+    """
+    x1, y1 = pos_1
+    x2, y2 = pos_2
+    dx = x1 - x2
+    dy = y1 - y2
+    return math.sqrt(dx**2 + dy**2)
+
+
+class SsAgent(mesa.Agent):
+    def __init__(
+        self, unique_id, pos, model, moore=False, sugar=0, metabolism=0, vision=0
+    ):
+        # first generation agents are randomly assigned metabolism and vision,
+        # children get a contribution from their parents
+
+        super().__init__(unique_id, model)
+        self.pos = pos
+        self.moore = moore
+        self.sugar = sugar
+        self.metabolism = metabolism
+        self.vision = vision
+        self.age = 0
+        self.age_of_death = self.random.randrange(60, 100)
+        self.fertility = self.random.randrange(10, 40)
+        self.gender = self.random.randint(0, 1)  # 0 is FEMALE, 1 is MALE
+
+    def is_occupied(self, pos):
+        this_cell = self.model.grid.get_cell_list_contents([pos])
+        return any(isinstance(agent, SsAgent) for agent in this_cell)
+
+    def childbearing_years(self) -> bool:
+        return True
+
+    def get_sugar(self, pos):
+        this_cell = self.model.grid.get_cell_list_contents([pos])
+        for agent in this_cell:
+            if type(agent) is Sugar:
+                return agent
+
+    def move(self):
+        # Get neighborhood within vision
+        neighbors = [
+            i
+            for i in self.model.grid.get_neighborhood(
+                self.pos, self.moore, False, radius=self.vision
+            )
+            if not self.is_occupied(i)
+        ]
+        neighbors.append(self.pos)
+        # Look for location with the most sugar
+        max_sugar = max(self.get_sugar(pos).amount for pos in neighbors)
+        candidates = [
+            pos for pos in neighbors if self.get_sugar(pos).amount == max_sugar
+        ]
+        # Narrow down to the nearest ones
+        min_dist = min(get_distance(self.pos, pos) for pos in candidates)
+        final_candidates = [
+            pos for pos in candidates if get_distance(self.pos, pos) == min_dist
+        ]
+        self.random.shuffle(final_candidates)
+        self.model.grid.move_agent(self, final_candidates[0])
+
+    def eat(self):
+        sugar_patch = self.get_sugar(self.pos)
+        self.sugar = self.sugar - self.metabolism + sugar_patch.amount
+        sugar_patch.amount = 0
+
+    def sex(self):
+        potential_mates = [
+            i
+            for i in self.model.grid.get_neighbors(
+                self.pos, self.moore, include_center=False, radius=self.vision
+            )
+            if
+            (  # also check for childbearing age
+                (type(i) is SsAgent)
+                and (i.sugar >= i.fertility)
+                and (i.gender != self.gender)
+            )
+        ]
+
+        # check for empty spots next to self
+        empty_cells = [
+            i
+            for i in self.model.grid.get_neighborhood(
+                self.pos, self.moore, include_center=False, radius=1
+            )
+            if not self.is_occupied(i)
+        ]
+        self.random.shuffle(empty_cells)
+        for neighbor in potential_mates:
+            if self.sugar < self.fertility:
+                break
+
+            if len(empty_cells) == 0:
+                continue  # placeholder
+                # check for first empty spot next to neighbor
+                # if none found iterate to next neighbor
+            endowment = (self.sugar / 2) + (neighbor.sugar / 2)
+            self.sugar -= self.sugar / 2
+            neighbor.sugar -= neighbor.sugar / 2
+            ssa = SsAgent(
+                self.model.next_id(),
+                empty_cells[0],
+                self.model,
+                False,
+                sugar=endowment,
+                metabolism=self.random.choice([neighbor.metabolism, self.metabolism]),
+                vision=self.random.choice([neighbor.vision, self.vision]),
+            )
+            self.model.grid.place_agent(ssa, empty_cells[0])
+            self.model.schedule.add(ssa)
+
+        # iterate through list
+
+    def step(self):
+        self.move()
+        self.eat()
+        if self.sugar >= self.fertility:  # also check for childbearing age
+            self.sex()  # sex condition(s)
+
+        if (self.sugar <= 0) or (self.age == self.age_of_death):
+            self.model.grid.remove_agent(self)
+            self.model.schedule.remove(self)  # death conditions
+        self.age += 1
+
+
+class Sugar(mesa.Agent):
+    def __init__(self, unique_id, pos, model, max_sugar, growback_rule=1):
+        super().__init__(unique_id, model)
+        self.amount = max_sugar
+        self.max_sugar = max_sugar
+        self.growback = growback_rule
+
+    def step(self):
+        self.amount = min([self.max_sugar, self.amount + self.growback])

examples/sugarscape_scc/sugarscape_scc/model.py

@@ -0,0 +1,95 @@
+"""
+Sugarscape Constant Growback Model
+================================
+
+Replication of the model found in Netlogo:
+Li, J. and Wilensky, U. (2009). NetLogo Sugarscape 2 Constant Growback model.
+http://ccl.northwestern.edu/netlogo/models/Sugarscape2ConstantGrowback.
+Center for Connected Learning and Computer-Based Modeling,
+Northwestern University, Evanston, IL.
+"""
+
+from pathlib import Path
+
+import mesa
+
+from .agents import SsAgent, Sugar
+
+
+class SugarscapeScc(mesa.Model):
+    """
+    Sugarscape 3 SCC
+    """
+
+    verbose = True  # Print-monitoring
+
+    def __init__(self, width=50, height=50, initial_population=100):
+        """
+        Create a new Constant Growback model with the given parameters.
+
+        Args:
+            initial_population: Number of population to start with
+        """
+        super().__init__()
+
+        # Set parameters
+        self.width = width
+        self.height = height
+        self.initial_population = initial_population
+        self.schedule = mesa.time.RandomActivationByType(self)
+        self.grid = mesa.space.MultiGrid(self.width, self.height, torus=False)
+        self.datacollector = mesa.DataCollector(
+            model_reporters={"SsAgent": lambda m: m.schedule.get_type_count(SsAgent)},
+            agent_reporters={
+                "Age": lambda a: a.age if (isinstance(a, SsAgent)) else None
+            },
+        )
+        # Create sugar
+        import numpy as np
+
+        sugar_distribution = np.genfromtxt(Path(__file__).parent / "sugar-map.txt")
+        for _, (x, y) in self.grid.coord_iter():
+            max_sugar = sugar_distribution[x, y]
+            sugar = Sugar(self.next_id(), (x, y), self, max_sugar)
+            self.grid.place_agent(sugar, (x, y))
+            self.schedule.add(sugar)
+
+        # Create agent:
+        for _ in range(self.initial_population):
+            x = self.random.randrange(self.width)
+            y = self.random.randrange(self.height)
+            sugar = self.random.randrange(50, 100)
+            metabolism = self.random.randrange(2, 4)
+            vision = self.random.randrange(1, 6)
+            ssa = SsAgent(
+                self.next_id(), (x, y), self, False, sugar, metabolism, vision
+            )
+            self.grid.place_agent(ssa, (x, y))
+            self.schedule.add(ssa)
+
+        self.running = True
+        self.datacollector.collect(self)
+
+    def step(self):
+        self.schedule.step()
+        # collect data
+        self.datacollector.collect(self)
+        if self.verbose:
+            print([self.schedule.time, self.schedule.get_type_count(SsAgent)])
+
+    def run_model(self, step_count=200):
+        if self.verbose:
+            print(
+                "Initial number Sugarscape Agent: ",
+                self.schedule.get_type_count(SsAgent),
+            )
+
+        for i in range(step_count):
+            self.step()
+
+        if self.verbose:
+            print("")
+            print(
+                "Final number Sugarscape Agent: ",
+                self.schedule.get_type_count(SsAgent),
+            )

examples/sugarscape_scc/sugarscape_scc/server.py

@@ -0,0 +1,40 @@
+import mesa
+
+# TODO implement age graph as well
+from .agents import SsAgent, Sugar
+from .model import SugarscapeScc
+
+color_dic = {4: "#005C00", 3: "#008300", 2: "#00AA00", 1: "#00F800"}
+
+
+def SsAgent_portrayal(agent):
+    if agent is None:
+        return
+
+    if type(agent) is SsAgent:
+        return {"Shape": "sugarscape_scc/resources/ant.png", "scale": 0.9, "Layer": 1}
+
+    elif type(agent) is Sugar:
+        color = color_dic[agent.amount] if agent.amount != 0 else "#D6F5D6"
+        return {
+            "Color": color,
+            "Shape": "rect",
+            "Filled": "true",
+            "Layer": 0,
+            "w": 1,
+            "h": 1,
+        }
+
+    return {}
+
+
+canvas_element = mesa.visualization.CanvasGrid(SsAgent_portrayal, 50, 50, 500, 500)
+chart_element = mesa.visualization.ChartModule(
+    [{"Label": "SsAgent", "Color": "#AA0000"}], data_collector_name="datacollector"
+)
+bar_graph = mesa.visualization.BarChartModule(
+    [{"Label": "age", "Color": "#AAAAAA"}], data_collector_name="datacollector"
+)
+server = mesa.visualization.ModularServer(
+    SugarscapeScc, [canvas_element, chart_element, bar_graph], "Sugarscape 3 SCC"
+)