GoL_fast: Add fast PropertyLayer implementation of Game of Life

A special implementation of Conway's Game of Life, using only the PropertyLayer, without needing a Grid or even any Agents.

Author: EwoutH

examples/conways_game_of_life_fast/model.py

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+import numpy as np
+from mesa import Model
+from mesa.space import PropertyLayer
+from scipy.signal import convolve2d
+
+# fmt: off
+class GameOfLifeModel(Model):
+    def __init__(self, width=10, height=10, alive_fraction=0.2):
+        super().__init__()
+        # Initialize the property layer for cell states
+        self.cell_layer = PropertyLayer("cells", width, height, False, dtype=bool)
+        # Randomly set cells to alive
+        self.cell_layer.data = np.random.choice([True, False], size=(width, height), p=[alive_fraction, 1 - alive_fraction])
+
+    def step(self):
+        self._advance_time()
+        # Define a kernel for counting neighbors. The kernel has 1s around the center cell (which is 0).
+        # This setup allows us to count the live neighbors of each cell when we apply convolution.
+        kernel = np.array([[1, 1, 1],
+                           [1, 0, 1],
+                           [1, 1, 1]])
+
+        # Count neighbors using convolution.
+        # convolve2d applies the kernel to each cell of the grid, summing up the values of neighbors.
+        # boundary="wrap" ensures that the grid wraps around, simulating a toroidal surface.
+        neighbor_count = convolve2d(self.cell_layer.data, kernel, mode="same", boundary="wrap")
+
+        # Apply Game of Life rules:
+        # 1. A live cell with 2 or 3 live neighbors survives, otherwise it dies.
+        # 2. A dead cell with exactly 3 live neighbors becomes alive.
+        # These rules are implemented using logical operations on the grid.
+        self.cell_layer.data = np.logical_or(
+            np.logical_and(self.cell_layer.data, np.logical_or(neighbor_count == 2, neighbor_count == 3)),
+            # Rule for live cells
+            np.logical_and(~self.cell_layer.data, neighbor_count == 3)  # Rule for dead cells
+        )