mirror of
https://github.com/vale981/ray
synced 2025-03-06 10:31:39 -05:00
128 lines
3.5 KiB
Python
128 lines
3.5 KiB
Python
from __future__ import absolute_import
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from __future__ import division
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from __future__ import print_function
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import os
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from ray.rllib.utils.annotations import DeveloperAPI
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@DeveloperAPI
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class EvaluatorInterface(object):
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"""This is the interface between policy optimizers and policy evaluation.
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See also: RolloutWorker
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"""
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@DeveloperAPI
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def sample(self):
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"""Returns a batch of experience sampled from this evaluator.
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This method must be implemented by subclasses.
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Returns:
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SampleBatch|MultiAgentBatch: A columnar batch of experiences
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(e.g., tensors), or a multi-agent batch.
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Examples:
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>>> print(ev.sample())
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SampleBatch({"obs": [1, 2, 3], "action": [0, 1, 0], ...})
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"""
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raise NotImplementedError
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@DeveloperAPI
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def learn_on_batch(self, samples):
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"""Update policies based on the given batch.
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This is the equivalent to apply_gradients(compute_gradients(samples)),
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but can be optimized to avoid pulling gradients into CPU memory.
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Either this or the combination of compute/apply grads must be
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implemented by subclasses.
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Returns:
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info: dictionary of extra metadata from compute_gradients().
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Examples:
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>>> batch = ev.sample()
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>>> ev.learn_on_batch(samples)
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"""
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grads, info = self.compute_gradients(samples)
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self.apply_gradients(grads)
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return info
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@DeveloperAPI
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def compute_gradients(self, samples):
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"""Returns a gradient computed w.r.t the specified samples.
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Either this or learn_on_batch() must be implemented by subclasses.
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Returns:
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(grads, info): A list of gradients that can be applied on a
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compatible evaluator. In the multi-agent case, returns a dict
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of gradients keyed by policy ids. An info dictionary of
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extra metadata is also returned.
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Examples:
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>>> batch = ev.sample()
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>>> grads, info = ev2.compute_gradients(samples)
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"""
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raise NotImplementedError
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@DeveloperAPI
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def apply_gradients(self, grads):
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"""Applies the given gradients to this evaluator's weights.
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Either this or learn_on_batch() must be implemented by subclasses.
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Examples:
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>>> samples = ev1.sample()
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>>> grads, info = ev2.compute_gradients(samples)
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>>> ev1.apply_gradients(grads)
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"""
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raise NotImplementedError
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@DeveloperAPI
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def get_weights(self):
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"""Returns the model weights of this Evaluator.
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This method must be implemented by subclasses.
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Returns:
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object: weights that can be set on a compatible evaluator.
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info: dictionary of extra metadata.
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Examples:
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>>> weights = ev1.get_weights()
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"""
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raise NotImplementedError
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@DeveloperAPI
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def set_weights(self, weights):
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"""Sets the model weights of this Evaluator.
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This method must be implemented by subclasses.
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Examples:
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>>> weights = ev1.get_weights()
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>>> ev2.set_weights(weights)
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"""
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raise NotImplementedError
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@DeveloperAPI
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def get_host(self):
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"""Returns the hostname of the process running this evaluator."""
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return os.uname()[1]
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@DeveloperAPI
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def apply(self, func, *args):
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"""Apply the given function to this evaluator instance."""
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return func(self, *args)
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