Add docstrings to core library components (#273)

Documentation style https://google.github.io/styleguide/pyguide.html

Co-authored-by: anishdiwan <anishdiwan@diwan-ubuntu20.04>

rl_games/algos_torch/a2c_continuous.py

@@ -10,8 +10,20 @@
 
 
 class A2CAgent(a2c_common.ContinuousA2CBase):
+    """Continuous PPO Agent
 
+    The A2CAgent class inerits from the continuous asymmetric actor-critic class and makes modifications for PPO.
+
+    """
     def __init__(self, base_name, params):
+        """Initialise the algorithm with passed params
+
+        Args:
+            base_name (:obj:`str`): Name passed on to the observer and used for checkpoints etc.
+            params (:obj `dict`): Algorithm parameters
+
+        """
+
         a2c_common.ContinuousA2CBase.__init__(self, base_name, params)
         obs_shape = self.obs_shape
         build_config = {
@@ -75,6 +87,14 @@ def get_masked_action_values(self, obs, action_masks):
         assert False
 
     def calc_gradients(self, input_dict):
+        """Compute gradients needed to step the networks of the algorithm.
+
+        Core algo logic is defined here
+
+        Args:
+            input_dict (:obj:`dict`): Algo inputs as a dict.
+
+        """
         value_preds_batch = input_dict['old_values']
         old_action_log_probs_batch = input_dict['old_logp_actions']
         advantage = input_dict['advantages']

rl_games/algos_torch/a2c_discrete.py

@@ -13,8 +13,19 @@
 
 
 class DiscreteA2CAgent(a2c_common.DiscreteA2CBase):
+    """Discrete PPO Agent
 
+    The DiscreteA2CAgent class inerits from the discrete asymmetric actor-critic class and makes modifications for PPO.
+
+    """
     def __init__(self, base_name, params):
+        """Initialise the algorithm with passed params
+
+        Args:
+            base_name (:obj:`str`): Name passed on to the observer and used for checkpoints etc.
+            params (:obj `dict`): Algorithm parameters
+
+        """
         a2c_common.DiscreteA2CBase.__init__(self, base_name, params)
         obs_shape = self.obs_shape
 
@@ -108,6 +119,14 @@ def train_actor_critic(self, input_dict):
         return self.train_result
 
     def calc_gradients(self, input_dict):
+        """Compute gradients needed to step the networks of the algorithm.
+
+        Core algo logic is defined here
+
+        Args:
+            input_dict (:obj:`dict`): Algo inputs as a dict.
+
+        """
         value_preds_batch = input_dict['old_values']
         old_action_log_probs_batch = input_dict['old_logp_actions']
         advantage = input_dict['advantages']

rl_games/common/env_configurations.py

@@ -253,6 +253,7 @@ def create_env(name, **kwargs):
         env = wrappers.TimeLimit(env, steps_limit)
     return env
 
+# Dictionary of env_name as key and a sub-dict containing env_type and a env-creator function
 configurations = {
     'CartPole-v1' : {
         'vecenv_type' : 'RAY',
@@ -458,4 +459,11 @@ def get_obs_and_action_spaces_from_config(config):
 
 
 def register(name, config):
+    """Add a new key-value pair to the known environments (configurations dict).
+
+    Args:
+        name (:obj:`str`): Name of the env to be added.
+        config (:obj:`dict`): Dictionary with env type and a creator function.
+
+    """
     configurations[name] = config

rl_games/common/object_factory.py

@@ -1,14 +1,39 @@
 class ObjectFactory:
+    """General-purpose class to instantiate some other base class from rl_games. Usual use case it to instantiate algos, players etc.
+
+    The ObjectFactory class is used to dynamically create any other object using a builder function (typically a lambda function).
+
+    """
+
     def __init__(self):
+        """Initialise a dictionary of builders with keys as `str` and values as functions.
+
+        """
         self._builders = {}
 
     def register_builder(self, name, builder):
+        """Register a passed builder by adding to the builders dict.
+
+        Initialises runners and players for all algorithms available in the library using `rl_games.common.object_factory.ObjectFactory`
+
+        Args:
+            name (:obj:`str`): Key of the added builder.
+            builder (:obj `func`): Function to return the requested object
+
+        """
         self._builders[name] = builder
 
     def set_builders(self, builders):
         self._builders = builders
 
     def create(self, name, **kwargs):
+        """Create the requested object by calling a registered builder function.
+
+        Args:
+            name (:obj:`str`): Key of the requested builder.
+            **kwargs: Arbitrary kwargs needed for the builder function
+
+        """
         builder = self._builders.get(name)
         if not builder:
             raise ValueError(name)

rl_games/common/vecenv.py

@@ -8,7 +8,20 @@
 import torch
 
 class RayWorker:
+    """Wrapper around a third-party (gym for example) environment class that enables parallel training.
+
+    The RayWorker class wraps around another environment class to enable the use of this 
+    environment within an asynchronous parallel training setup
+
+    """
     def __init__(self, config_name, config):
+        """Initialise the class. Sets up the environment creator using the `rl_games.common.env_configurations.configuraitons` dict
+
+        Args:
+            config_name (:obj:`str`): Key of the environment to create.
+            config: Misc. kwargs passed on to the environment creator function
+
+        """
         self.env = configurations[config_name]['env_creator'](**config)
 
     def _obs_to_fp32(self, obs):
@@ -27,6 +40,12 @@ def _obs_to_fp32(self, obs):
         return obs
 
     def step(self, action):
+        """Step the environment and reset if done
+
+        Args:
+            action (type depends on env): Action to take.
+
+        """
         next_state, reward, is_done, info = self.env.step(action)
 
         if np.isscalar(is_done):
@@ -95,9 +114,23 @@ def get_env_info(self):
 
 
 class RayVecEnv(IVecEnv):
+    """Main env class that manages several `rl_games.common.vecenv.Rayworker` objects for parallel training
+    
+    The RayVecEnv class manages a set of individual environments and wraps around the methods from RayWorker.
+    Each worker is executed asynchronously.
+
+    """
     import ray
 
     def __init__(self, config_name, num_actors, **kwargs):
+        """Initialise the class. Sets up the config for the environment and creates individual workers to manage.
+
+        Args:
+            config_name (:obj:`str`): Key of the environment to create.
+            num_actors (:obj:`int`): Number of environments (actors) to create
+            **kwargs: Misc. kwargs passed on to the environment creator function within the RayWorker __init__
+
+        """
         self.config_name = config_name
         self.num_actors = num_actors
         self.use_torch = False
@@ -131,6 +164,14 @@ def __init__(self, config_name, num_actors, **kwargs):
             self.concat_func = np.concatenate
 
     def step(self, actions):
+        """Step all individual environments (using the created workers). 
+        Returns a concatenated array of observations, rewards, done states, and infos if the env allows concatenation.
+        Else returns a nested dict.
+
+        Args:
+            action (type depends on env): Action to take.
+
+        """
         newobs, newstates, newrewards, newdones, newinfos = [], [], [], [], []
         res_obs = []
         if self.num_agents == 1:
@@ -218,6 +259,12 @@ def reset(self):
 vecenv_config = {}
 
 def register(config_name, func):
+    """Add an environment type (for example RayVecEnv) to the list of available types `rl_games.common.vecenv.vecenv_config`
+    Args:
+        config_name (:obj:`str`): Key of the environment to create.
+        func (:obj:`func`): Function that creates the environment 
+
+    """
     vecenv_config[config_name] = func
 
 def create_vec_env(config_name, num_actors, **kwargs):

rl_games/torch_runner.py

@@ -31,8 +31,24 @@ def _override_sigma(agent, args):
 
 
 class Runner:
+    """Runs training/inference (playing) procedures as per a given configuration.
+
+    The Runner class provides a high-level API for instantiating agents for either training or playing
+    with an RL algorithm. It further logs training metrics.
+
+    """
 
     def __init__(self, algo_observer=None):
+        """Initialise the runner instance with algorithms and observers.
+
+        Initialises runners and players for all algorithms available in the library using `rl_games.common.object_factory.ObjectFactory`
+
+        Args:
+            algo_observer (:obj:`rl_games.common.algo_observer.AlgoObserver`, optional): Algorithm observer that logs training metrics.
+                Defaults to `rl_games.common.algo_observer.DefaultAlgoObserver`
+
+        """
+
         self.algo_factory = object_factory.ObjectFactory()
         self.algo_factory.register_builder('a2c_continuous', lambda **kwargs : a2c_continuous.A2CAgent(**kwargs))
         self.algo_factory.register_builder('a2c_discrete', lambda **kwargs : a2c_discrete.DiscreteA2CAgent(**kwargs)) 
@@ -55,6 +71,13 @@ def reset(self):
         pass
 
     def load_config(self, params):
+        """Loads passed config params.
+
+        Args:
+            params (:obj:`dict`): Parameters passed in as a dict obtained from a yaml file or some other config format.
+
+        """
+
         self.seed = params.get('seed', None)
         if self.seed is None:
             self.seed = int(time.time())
@@ -109,13 +132,25 @@ def load(self, yaml_config):
         self.load_config(params=self.default_config)
 
     def run_train(self, args):
+        """Run the training procedure from the algorithm passed in.
+
+        Args:
+            args (:obj:`dict`): Train specific args passed in as a dict obtained from a yaml file or some other config format.
+
+        """
         print('Started to train')
         agent = self.algo_factory.create(self.algo_name, base_name='run', params=self.params)
         _restore(agent, args)
         _override_sigma(agent, args)
         agent.train()
 
     def run_play(self, args):
+        """Run the inference procedure from the algorithm passed in.
+
+        Args:
+            args (:obj:`dict`): Playing specific args passed in as a dict obtained from a yaml file or some other config format.
+
+        """
         print('Started to play')
         player = self.create_player()
         _restore(player, args)
@@ -129,6 +164,12 @@ def reset(self):
         pass
 
     def run(self, args):
+        """Run either train/play depending on the args.
+
+        Args:
+            args (:obj:`dict`):  Args passed in as a dict obtained from a yaml file or some other config format.
+
+        """        
         if args['train']:
             self.run_train(args)
         elif args['play']: