use PropertyLayer to store cliff cell information

mesa/examples/advanced/wolf_sheep/agents.py

@@ -39,7 +39,12 @@ def feed(self):
     def step(self):
         """Execute one step of the animal's behavior."""
         # Move to random neighboring cell
-        self.cell = self.cell.neighborhood.select_random_cell()
+        self.cell = self.cell.neighborhood.select_random_cell() 
+        is_cliff = self.model.grid.cliff.data[self.cell.coordinate[0]][self.cell.coordinate[1]]
+        if is_cliff: # if it is a cliff, then the animal dies
+            self.remove()
+            return
+
         self.energy -= 1
 
         # Try to feed

mesa/examples/advanced/wolf_sheep/model.py

@@ -92,19 +92,19 @@ def __init__(
 
         self.datacollector = DataCollector(model_reporters)
 
-        obstructionArr = [[False]*self.width for i in range(self.height)]
+        cliff_arr = [[False]*self.width for i in range(self.height)]
 
-        obstructionCoord = set([(random.randrange(self.height), random.randrange(self.width)) for i in range(10)] ) # set is used because the random number gen might return the same coordinate
-        for i,j in obstructionCoord:
-            obstructionArr[i][j] = True
+        cliff_coord = set([(random.randrange(self.height), random.randrange(self.width)) for i in range((width*height)//3)] ) # set is used because the random number gen might return the same coordinate
+        for i,j in cliff_coord:
+            cliff_arr[i][j] = True
 
-        obstructionArr = np.array(obstructionArr)
+        cliff_arr = np.array(cliff_arr)
 
-        self.grid.add_property_layer(PropertyLayer.from_data("obstruction", obstructionArr))
+        self.grid.add_property_layer(PropertyLayer.from_data("cliff", cliff_arr))
 
         possibleCells = []
         for cell in self.grid.all_cells.cells:
-            if (cell.coordinate[0], cell.coordinate[1]) not in obstructionCoord: # so we don't create wolf or sheep on obstructed cells
+            if (cell.coordinate[0], cell.coordinate[1]) not in cliff_coord: # so we don't create wolf or sheep on cliff cells
                 possibleCells.append(cell)
 
         # Create sheep: