Implement a goal base reward function

mujoco_maze/__init__.py

@@ -3,11 +3,18 @@ import gym
 MAZE_IDS = ["Maze", "Push", "Fall", "Block", "BlockMaze"]
 
 
+def _get_kwargs(maze_id: str) -> tuple:
+    return {
+        "observe_blocks": maze_id in ["Block", "BlockMaze"],
+        "pin_spin_near_agent": maze_id in ["Block", "BlockMaze"],
+    }
+
+
 for maze_id in MAZE_IDS:
     gym.envs.register(
         id="AntMaze{}-v0".format(maze_id),
         entry_point="mujoco_maze.ant_maze_env:AntMazeEnv",
-        kwargs=dict(maze_id=maze_id, manual_collision=True),
+        kwargs=dict(maze_id=maze_id, maze_size_scaling=8, **_get_kwargs(maze_id)),
         max_episode_steps=1000,
         reward_threshold=-1000,
     )
@@ -16,7 +23,12 @@ for maze_id in MAZE_IDS:
     gym.envs.register(
         id="PointMaze{}-v0".format(maze_id),
         entry_point="mujoco_maze.point_maze_env:PointMazeEnv",
-        kwargs=dict(maze_id=maze_id, manual_collision=True),
+        kwargs=dict(
+            maze_id=maze_id,
+            maze_size_scaling=4,
+            manual_collision=True,
+            **_get_kwargs(maze_id),
+        ),
         max_episode_steps=1000,
         reward_threshold=-1000,
     )

mujoco_maze/agent_model.py

@@ -36,4 +36,3 @@ class AgentModel(ABC, MujocoEnv, EzPickle):
     @abstractmethod
     def get_ori(self) -> float:
         pass
-

mujoco_maze/maze_env.py

@@ -22,7 +22,7 @@ import math
 import numpy as np
 import gym
 
-from typing import Type
+from typing import Callable, Type, Union
 
 from mujoco_maze.agent_model import AgentModel
 from mujoco_maze import maze_env_utils
@@ -49,6 +49,8 @@ class MazeEnv(gym.Env):
         put_spin_near_agent=False,
         top_down_view=False,
         manual_collision=False,
+        dense_reward=True,
+        goal_sampler: Union[str, np.ndarray, Callable[[], np.ndarray]] = "default",
         *args,
         **kwargs,
     ):
@@ -162,7 +164,7 @@ class MazeEnv(gym.Env):
                     )
                 elif maze_env_utils.can_move(struct):  # Movable block.
                     # The "falling" blocks are shrunk slightly and increased in mass to
-                    # ensure that it can fall easily through a gap in the platform blocks.
+                    # ensure it can fall easily through a gap in the platform blocks.
                     name = "movable_%d_%d" % (i, j)
                     self.movable_blocks.append((name, struct))
                     falling = maze_env_utils.can_move_z(struct)
@@ -265,6 +267,29 @@ class MazeEnv(gym.Env):
         tree.write(file_path)
         self.wrapped_env = self.MODEL_CLASS(*args, file_path=file_path, **kwargs)
 
+        # Set reward function
+        self._reward_fn = _reward_fn(maze_id, dense_reward)
+
+        # Set goal sampler
+        if isinstance(goal_sampler, str):
+            if goal_sampler == "random":
+                self._goal_sampler = lambda: np.random.uniform((-4, -4), (20, 20))
+            elif goal_sampler == "default":
+                default_goal = _default_goal(maze_id)
+                self._goal_sampler = lambda: default_goal
+            else:
+                raise NotImplementedError(f"Unknown goal_sampler: {goal_sampler}")
+        elif isinstance(goal_sampler, np.ndarray):
+            self._goal_sampler = lambda: goal_sampler
+        elif callable(goal_sampler):
+            self._goal_sampler = goal_sampler
+        else:
+            raise ValueError(f"Invalid goal_sampler: {goal_sampler}")
+        self.goal = self._goal_sampler()
+
+        # Set goal function
+        self._goal_fn = _goal_fn(maze_id)
+
     def get_ori(self):
         return self.wrapped_env.get_ori()
 
@@ -472,6 +497,8 @@ class MazeEnv(gym.Env):
     def reset(self):
         self.t = 0
         self.wrapped_env.reset()
+        # Sample a new goal
+        self.goal = self._goal_sampler()
         if len(self._init_positions) > 1:
             xy = np.random.choice(self._init_positions)
             self.wrapped_env.set_xy(xy)
@@ -529,15 +556,57 @@ class MazeEnv(gym.Env):
                         return True
         return False
 
+    def _is_in_goal(self, pos):
+        (np.linalg.norm(obs[:3] - goal) <= 0.6)
+
     def step(self, action):
         self.t += 1
         if self._manual_collision:
             old_pos = self.wrapped_env.get_xy()
-            inner_next_obs, inner_reward, done, info = self.wrapped_env.step(action)
+            inner_next_obs, inner_reward, _, info = self.wrapped_env.step(action)
             new_pos = self.wrapped_env.get_xy()
             if self._is_in_collision(new_pos):
                 self.wrapped_env.set_xy(old_pos)
         else:
-            inner_next_obs, inner_reward, done, info = self.wrapped_env.step(action)
+            inner_next_obs, inner_reward, _, info = self.wrapped_env.step(action)
         next_obs = self._get_obs()
-        return next_obs, inner_reward, False, info
+        outer_reward = self._reward_fn(next_obs, self.goal)
+        done = self._goal_fn(next_obs, self.goal)
+        return next_obs, inner_reward + outer_reward, done, info
+
+
+def _goal_fn(maze_id: str) -> callable:
+    if maze_id in ["Maze", "Push"]:
+        return lambda obs, goal: np.linalg.norm(obs[:2] - goal) <= 0.6
+    elif maze_id == "Fall":
+        return lambda obs, goal: np.linalg.norm(obs[:3] - goal) <= 0.6
+    else:
+        raise NotImplementedError(f"Unknown maze id: {maze_id}")
+
+
+def _reward_fn(maze_id: str, dense: str) -> callable:
+    if dense:
+        if maze_id in ["Maze", "Push"]:
+            return lambda obs, goal: -np.sum(np.square(obs[:2] - goal)) ** 0.5
+        elif maze_id == "Fall":
+            return lambda obs, goal: -np.sum(np.square(obs[:3] - goal)) ** 0.5
+        else:
+            raise NotImplementedError(f"Unknown maze id: {maze_id}")
+    else:
+        if maze_id in ["Maze", "Push"]:
+            return lambda obs, goal: (np.linalg.norm(obs[:2] - goal) <= 0.6) * 1.0
+        elif maze_id == "Fall":
+            return lambda obs, goal: (np.linalg.norm(obs[:3] - goal) <= 0.6) * 1.0
+        else:
+            raise NotImplementedError(f"Unknown maze id: {maze_id}")
+
+
+def _default_goal(maze_id: str) -> np.ndarray:
+    if maze_id == "Maze":
+        return np.array([0.0, 8.0])
+    elif maze_id == "Push":
+        return np.array([0.0, 19.0])
+    elif maze_id == "Fall":
+        return np.array([0.0, 27.0, 4.5])
+    else:
+        raise NotImplementedError(f"Unknown maze id: {maze_id}")