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* updating the documentation website * adding the built docs * update of api docstrings across coach and tutorials 0-2 * added some missing api documentation * New Sphinx based documentation
81 lines
4.1 KiB
ReStructuredText
81 lines
4.1 KiB
ReStructuredText
Adding a New Agent
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==================
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Coach's modularity makes adding an agent a simple and clean task.
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We suggest using the following
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`Jupyter notebook tutorial <https://github.com/NervanaSystems/coach/blob/master/tutorials/1.%20Implementing%20an%20Algorithm.ipynb>`_
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to ramp up on this process. In general, it involves the following steps:
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1. Implement your algorithm in a new file. The agent can inherit base classes such as **ValueOptimizationAgent** or
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**ActorCriticAgent**, or the more generic **Agent** base class.
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.. note::
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**ValueOptimizationAgent**, **PolicyOptimizationAgent** and **Agent** are abstract classes.
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:code:`learn_from_batch()` should be overriden with the desired behavior for the algorithm being implemented.
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If deciding to inherit from **Agent**, also :code:`choose_action()` should be overriden.
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.. code-block:: python
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def learn_from_batch(self, batch) -> Tuple[float, List, List]:
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"""
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Given a batch of transitions, calculates their target values and updates the network.
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:param batch: A list of transitions
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:return: The total loss of the training, the loss per head and the unclipped gradients
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"""
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def choose_action(self, curr_state):
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"""
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choose an action to act with in the current episode being played. Different behavior might be exhibited when training
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or testing.
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:param curr_state: the current state to act upon.
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:return: chosen action, some action value describing the action (q-value, probability, etc)
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"""
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2. Implement your agent's specific network head, if needed, at the implementation for the framework of your choice.
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For example **architectures/neon_components/heads.py**. The head will inherit the generic base class Head.
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A new output type should be added to configurations.py, and a mapping between the new head and output type should
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be defined in the get_output_head() function at **architectures/neon_components/general_network.py**
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3. Define a new parameters class that inherits AgentParameters.
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The parameters class defines all the hyperparameters for the agent, and is initialized with 4 main components:
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* **algorithm**: A class inheriting AlgorithmParameters which defines any algorithm specific parameters
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* **exploration**: A class inheriting ExplorationParameters which defines the exploration policy parameters.
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There are several common exploration policies built-in which you can use, and are defined under
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the exploration sub directory. You can also define your own custom exploration policy.
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* **memory**: A class inheriting MemoryParameters which defined the memory parameters.
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There are several common memory types built-in which you can use, and are defined under the memories
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sub directory. You can also define your own custom memory.
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* **networks**: A dictionary defining all the networks that will be used by the agent. The keys of the dictionary
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define the network name and will be used to access each network through the agent class.
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The dictionary values are a class inheriting NetworkParameters, which define the network structure
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and parameters.
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Additionally, set the path property to return the path to your agent class in the following format:
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:code:`<path to python module>:<name of agent class>`
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For example,
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.. code-block:: python
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class RainbowAgentParameters(AgentParameters):
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def __init__(self):
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super().__init__(algorithm=RainbowAlgorithmParameters(),
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exploration=RainbowExplorationParameters(),
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memory=RainbowMemoryParameters(),
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networks={"main": RainbowNetworkParameters()})
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@property
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def path(self):
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return 'rainbow.rainbow_agent:RainbowAgent'
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4. (Optional) Define a preset using the new agent type with a given environment, and the hyper-parameters that should
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be used for training on that environment.
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