Add configurable center obstacle size to Pursuit

pettingzoo/env_registry/__init__.py

@@ -111,7 +111,7 @@ def _maybe_register_parallel(
 
 _sisl_envs = [
     ("multiwalker_v9", "multiwalker"),
-    ("pursuit_v5", "pursuit"),
+    ("pursuit_v6", "pursuit"),
 ]
 
 for _id, _base in _sisl_envs:

pettingzoo/sisl/all_modules.py

@@ -1,6 +1,6 @@
-from pettingzoo.sisl import multiwalker_v9, pursuit_v5
+from pettingzoo.sisl import multiwalker_v9, pursuit_v6
 
 sisl_environments = {
     "sisl/multiwalker_v9": multiwalker_v9,
-    "sisl/pursuit_v5": pursuit_v5,
+    "sisl/pursuit_v6": pursuit_v6,
 }

pettingzoo/sisl/pursuit/manual_policy.py

@@ -50,14 +50,14 @@ def available_agents(self):
 
 
 if __name__ == "__main__":
-    from pettingzoo.sisl import pursuit_v5
+    from pettingzoo.sisl import pursuit_v6
 
     clock = pygame.time.Clock()
 
-    env = pursuit_v5.env()
+    env = pursuit_v6.env()
     env.reset()
 
-    manual_policy = pursuit_v5.ManualPolicy(env)
+    manual_policy = pursuit_v6.ManualPolicy(env)
 
     for agent in env.agent_iter():
         clock.tick(env.metadata["render_fps"])

pettingzoo/sisl/pursuit/pursuit.py

@@ -9,7 +9,7 @@
 
 This environment is part of the <a href='..'>SISL environments</a>. Please read that page first for general information.
 
-| Creation             | `make("aec", "sisl/pursuit-v5")`                       |
+| Creation             | `make("aec", "sisl/pursuit-v6")`                       |
 |----------------------|--------------------------------------------------------|
 | Actions              | Discrete                                               |
 | Parallel API         | Yes                                                    |
@@ -32,6 +32,18 @@
 
 The state takes the full form of `(y_size, x_size, 3)`, with the same three channels as the observations, but covering the whole map instead of the `obs_range` box around each agent.
 
+### Center obstacle
+
+The `center_box_size` argument controls the size of the centered obstacle in
+grid cells. Pass a `(width, height)` tuple to set an explicit size, for example
+`center_box_size=(4, 2)`. Passing `(0, 0)` removes the obstacle entirely, while
+the default `None` preserves the obstacle dimensions used by earlier versions
+of Pursuit.
+
+Both dimensions must be non-negative integers, cannot exceed the corresponding
+map dimension, and cannot cover the entire map. This argument was introduced in
+`pursuit_v6`; code using `pursuit_v5` must update its import to use it.
+
 ### Manual Control
 
 Select different pursuers with 'J' and 'K'. The selected pursuer can be moved with the arrow keys.
@@ -42,9 +54,10 @@
 ```python
 from pettingzoo import make
 
-make("aec", "sisl/pursuit-v5", max_cycles=500, x_size=16, y_size=16, shared_reward=True,
+make("aec", "sisl/pursuit-v6", max_cycles=500, x_size=16, y_size=16, shared_reward=True,
 n_evaders=30, n_pursuers=8, obs_range=7, n_catch=2, freeze_evaders=False, tag_reward=0.01,
-catch_reward=5.0, urgency_reward=-0.1, surround=True, constraint_window=1.0)
+catch_reward=5.0, urgency_reward=-0.1, surround=True, constraint_window=1.0,
+center_box_size=None)
 ```
 
 `x_size, y_size`: Size of environment world space
@@ -71,11 +84,14 @@
 
 `constraint_window`: Size of box (from center, in proportional units) which agents can randomly spawn into the environment world. Default is 1.0, which means they can spawn anywhere on the map. A value of 0 means all agents spawn in the center.
 
+`center_box_size`: Optional `(width, height)` of the center obstacle in grid cells. The default `None` preserves the original proportional obstacle size. Use `(0, 0)` for a map without a center obstacle.
+
 `max_cycles`:  After max_cycles steps all agents will return done
 
 
 ### Version History
 
+* v6: Add `center_box_size` to control or remove the center obstacle
 * v5: Add state() and state space support (1.27.0)
 * v4: Change the reward sharing, fix a collection bug, add agent counts to the rendering (1.14.0)
 * v3: Observation space bug fixed (1.5.0)
@@ -110,7 +126,7 @@ def env(**kwargs):
 class raw_env(AECEnv, EzPickle):
     metadata = {
         "render_modes": ["human", "rgb_array"],
-        "name": "pursuit_v5",
+        "name": "pursuit_v6",
         "is_parallelizable": True,
         "render_fps": 5,
         "has_manual_policy": True,

pettingzoo/sisl/pursuit/pursuit_base.py

@@ -35,6 +35,7 @@ def __init__(
         surround: bool = True,
         render_mode=None,
         constraint_window: float = 1.0,
+        center_box_size: tuple[int, int] | None = None,
     ):
         """In evade pursuit a set of pursuers must 'tag' a set of evaders.
 
@@ -57,10 +58,13 @@ def __init__(
         urgency_reward: reward added in each step
         surround: toggles surround condition for evader removal
         constraint_window: window in which agents can randomly spawn
+        center_box_size: width and height of the center obstacle in grid cells
         """
         self.x_size = x_size
         self.y_size = y_size
-        self.map_matrix = two_d_maps.rectangle_map(self.x_size, self.y_size)
+        self.map_matrix = two_d_maps.rectangle_map(
+            self.x_size, self.y_size, center_box_size=center_box_size
+        )
         self.max_cycles = max_cycles
         self._seed()
 

pettingzoo/sisl/pursuit/test_pursuit.py

@@ -1,11 +1,13 @@
 import numpy as np
+import pytest
 
-from pettingzoo.sisl import pursuit_v5
+from pettingzoo.sisl import pursuit_v6
+from pettingzoo.sisl.pursuit.utils import two_d_maps
 
 
 def test_state_matches_model_state():
     # use a non-square map so axis ordering mistakes are caught
-    env = pursuit_v5.env(x_size=8, y_size=19, max_cycles=40)
+    env = pursuit_v6.env(x_size=8, y_size=19, max_cycles=40)
     env.reset(seed=42)
     base_env = env.unwrapped.env
     for agent in env.agent_iter(env.num_agents * 4):
@@ -22,7 +24,7 @@ def test_state_matches_model_state():
 
 
 def test_observations_are_crops_of_state():
-    env = pursuit_v5.env(max_cycles=40)
+    env = pursuit_v6.env(max_cycles=40)
     env.reset(seed=0)
     base_env = env.unwrapped.env
     for agent in env.agent_iter(env.num_agents * 4):
@@ -40,7 +42,61 @@ def test_observations_are_crops_of_state():
 
 
 def test_parallel_state():
-    par_env = pursuit_v5.parallel_env(max_cycles=40)
+    par_env = pursuit_v6.parallel_env(max_cycles=40)
     par_env.reset(seed=42)
     state = par_env.state()
     assert par_env.state_space.contains(state)
+
+
+def test_center_box_size():
+    env = pursuit_v6.env(
+        x_size=8,
+        y_size=10,
+        n_evaders=1,
+        n_pursuers=1,
+        center_box_size=(4, 2),
+    )
+    expected_map = np.zeros((8, 10), dtype=np.int32)
+    expected_map[2:6, 4:6] = -1
+    assert np.array_equal(env.unwrapped.env.map_matrix, expected_map)
+
+
+def test_zero_center_box_size_removes_obstacle():
+    env = pursuit_v6.env(
+        x_size=8,
+        y_size=10,
+        n_evaders=1,
+        n_pursuers=1,
+        center_box_size=(0, 0),
+    )
+    assert np.count_nonzero(env.unwrapped.env.map_matrix) == 0
+
+
+def test_default_center_box_size_is_unchanged():
+    env = pursuit_v6.env(n_evaders=1, n_pursuers=1)
+    assert np.array_equal(
+        env.unwrapped.env.map_matrix,
+        two_d_maps.rectangle_map(env.unwrapped.env.x_size, env.unwrapped.env.y_size),
+    )
+
+
+@pytest.mark.parametrize(
+    ("center_box_size", "error"),
+    [
+        ([2, 2], TypeError),
+        ((2,), TypeError),
+        ((2.0, 2), TypeError),
+        ((-1, 2), ValueError),
+        ((9, 2), ValueError),
+        ((8, 10), ValueError),
+    ],
+)
+def test_invalid_center_box_size(center_box_size, error):
+    with pytest.raises(error):
+        pursuit_v6.env(
+            x_size=8,
+            y_size=10,
+            n_evaders=1,
+            n_pursuers=1,
+            center_box_size=center_box_size,
+        )

pettingzoo/sisl/pursuit/utils/two_d_maps.py

@@ -2,13 +2,41 @@
 from scipy.ndimage import zoom
 
 
-def rectangle_map(xs, ys, xb=0.3, yb=0.2):
-    """Returns a 2D 'map' with a rectangle building centered in the middle.
+def rectangle_map(xs, ys, xb=0.3, yb=0.2, center_box_size=None):
+    """Returns a 2D map with a rectangle building centered in the middle.
 
-    Map is a 2D numpy array
-    xb and yb are buffers for each dim representing the raio of the map to leave open on each side
+    ``center_box_size`` is an optional ``(width, height)`` tuple measured in
+    grid cells. When omitted, the historical proportional sizing controlled by
+    ``xb`` and ``yb`` is preserved.
     """
     rmap = np.zeros((xs, ys), dtype=np.int32)
+
+    if center_box_size is not None:
+        if (
+            not isinstance(center_box_size, tuple)
+            or len(center_box_size) != 2
+            or any(
+                not isinstance(size, int) or isinstance(size, bool)
+                for size in center_box_size
+            )
+        ):
+            raise TypeError("center_box_size must be a tuple of two integers or None")
+
+        box_width, box_height = center_box_size
+        if box_width < 0 or box_height < 0:
+            raise ValueError("center_box_size dimensions must be non-negative")
+        if box_width > xs or box_height > ys:
+            raise ValueError(
+                "center_box_size dimensions cannot exceed the map dimensions"
+            )
+        if box_width == xs and box_height == ys:
+            raise ValueError("center_box_size must leave at least one free grid cell")
+
+        x_start = (xs - box_width) // 2
+        y_start = (ys - box_height) // 2
+        rmap[x_start : x_start + box_width, y_start : y_start + box_height] = -1
+        return rmap
+
     for i in range(xs):
         for j in range(ys):
             # are we in the rectnagle in x dim?

test/all_parameter_combs_test.py

@@ -46,7 +46,7 @@
     texas_holdem_v4,
     tictactoe_v3,
 )
-from pettingzoo.sisl import multiwalker_v9, pursuit_v5
+from pettingzoo.sisl import multiwalker_v9, pursuit_v6
 from pettingzoo.test import max_cycles_test, parallel_api_test
 from pettingzoo.test.api_test import api_test
 from pettingzoo.test.render_test import render_test
@@ -230,17 +230,22 @@
         multiwalker_v9,
         {"terminate_on_fall": False, "remove_on_fall": False, "max_cycles": 50},
     ],
-    ["sisl/pursuit_v5", pursuit_v5, {"max_cycles": 50}],
-    ["sisl/pursuit_v5", pursuit_v5, {"x_size": 8, "y_size": 19, "max_cycles": 50}],
-    ["sisl/pursuit_v5", pursuit_v5, {"shared_reward": True, "max_cycles": 50}],
+    ["sisl/pursuit_v6", pursuit_v6, {"max_cycles": 50}],
+    ["sisl/pursuit_v6", pursuit_v6, {"x_size": 8, "y_size": 19, "max_cycles": 50}],
+    ["sisl/pursuit_v6", pursuit_v6, {"shared_reward": True, "max_cycles": 50}],
     [
-        "sisl/pursuit_v5",
-        pursuit_v5,
+        "sisl/pursuit_v6",
+        pursuit_v6,
         {"n_evaders": 5, "n_pursuers": 16, "max_cycles": 50},
     ],
-    ["sisl/pursuit_v5", pursuit_v5, {"obs_range": 15, "max_cycles": 50}],
-    ["sisl/pursuit_v5", pursuit_v5, {"n_catch": 3, "max_cycles": 50}],
-    ["sisl/pursuit_v5", pursuit_v5, {"freeze_evaders": True, "max_cycles": 50}],
+    ["sisl/pursuit_v6", pursuit_v6, {"obs_range": 15, "max_cycles": 50}],
+    ["sisl/pursuit_v6", pursuit_v6, {"n_catch": 3, "max_cycles": 50}],
+    ["sisl/pursuit_v6", pursuit_v6, {"freeze_evaders": True, "max_cycles": 50}],
+    [
+        "sisl/pursuit_v6",
+        pursuit_v6,
+        {"center_box_size": (4, 2), "max_cycles": 50},
+    ],
 ]
 
 

test/pygame_init_test.py

@@ -18,7 +18,7 @@
     texas_holdem_v4,
     tictactoe_v3,
 )
-from pettingzoo.sisl import multiwalker_v9, pursuit_v5
+from pettingzoo.sisl import multiwalker_v9, pursuit_v6
 
 pygame_envs = [
     cooperative_pong_v6,
@@ -32,7 +32,7 @@
     texas_holdem_v4,
     tictactoe_v3,
     multiwalker_v9,
-    pursuit_v5,
+    pursuit_v6,
 ]