ray/rllib/utils/exploration/random.py
Sven Mika 43043ee4d5
[RLlib] Tf2x preparation; part 2 (upgrading try_import_tf()). (#9136)
* WIP.

* Fixes.

* LINT.

* WIP.

* WIP.

* Fixes.

* Fixes.

* Fixes.

* Fixes.

* WIP.

* Fixes.

* Test

* Fix.

* Fixes and LINT.

* Fixes and LINT.

* LINT.
2020-06-30 10:13:20 +02:00

128 lines
5.2 KiB
Python

from gym.spaces import Discrete, Box, MultiDiscrete
import numpy as np
import tree
from typing import Union
from ray.rllib.models.action_dist import ActionDistribution
from ray.rllib.utils.annotations import override
from ray.rllib.utils.exploration.exploration import Exploration
from ray.rllib.utils import force_tuple
from ray.rllib.utils.framework import try_import_tf, try_import_torch, \
TensorType
from ray.rllib.utils.spaces.space_utils import get_base_struct_from_space
tf1, tf, tfv = try_import_tf()
torch, _ = try_import_torch()
class Random(Exploration):
"""A random action selector (deterministic/greedy for explore=False).
If explore=True, returns actions randomly from `self.action_space` (via
Space.sample()).
If explore=False, returns the greedy/max-likelihood action.
"""
def __init__(self, action_space, *, model, framework, **kwargs):
"""Initialize a Random Exploration object.
Args:
action_space (Space): The gym action space used by the environment.
framework (Optional[str]): One of None, "tf", "torch".
"""
super().__init__(
action_space=action_space,
model=model,
framework=framework,
**kwargs)
self.action_space_struct = get_base_struct_from_space(
self.action_space)
@override(Exploration)
def get_exploration_action(self,
*,
action_distribution: ActionDistribution,
timestep: Union[int, TensorType],
explore: bool = True):
# Instantiate the distribution object.
if self.framework == "tf":
return self.get_tf_exploration_action_op(action_distribution,
explore)
else:
return self.get_torch_exploration_action(action_distribution,
explore)
def get_tf_exploration_action_op(self, action_dist, explore):
def true_fn():
batch_size = 1
req = force_tuple(
action_dist.required_model_output_shape(
self.action_space, self.model.model_config))
# Add a batch dimension?
if len(action_dist.inputs.shape) == len(req) + 1:
batch_size = tf.shape(action_dist.inputs)[0]
# Function to produce random samples from primitive space
# components: (Multi)Discrete or Box.
def random_component(component):
if isinstance(component, Discrete):
return tf.random.uniform(
shape=(batch_size, ) + component.shape,
maxval=component.n,
dtype=component.dtype)
elif isinstance(component, MultiDiscrete):
return tf.random.uniform(
shape=(batch_size, ) + component.shape,
maxval=component.nvec,
dtype=component.dtype)
elif isinstance(component, Box):
if component.bounded_above.all() and \
component.bounded_below.all():
return tf.random.uniform(
shape=(batch_size, ) + component.shape,
minval=component.low,
maxval=component.high,
dtype=component.dtype)
else:
return tf.random.normal(
shape=(batch_size, ) + component.shape,
dtype=component.dtype)
actions = tree.map_structure(random_component,
self.action_space_struct)
return actions
def false_fn():
return action_dist.deterministic_sample()
action = tf.cond(
pred=tf.constant(explore, dtype=tf.bool)
if isinstance(explore, bool) else explore,
true_fn=true_fn,
false_fn=false_fn)
# TODO(sven): Move into (deterministic_)sample(logp=True|False)
batch_size = tf.shape(tree.flatten(action)[0])[0]
logp = tf.zeros(shape=(batch_size, ), dtype=tf.float32)
return action, logp
def get_torch_exploration_action(self, action_dist, explore):
if explore:
req = force_tuple(
action_dist.required_model_output_shape(
self.action_space, self.model.model_config))
# Add a batch dimension?
if len(action_dist.inputs.shape) == len(req) + 1:
batch_size = action_dist.inputs.shape[0]
a = np.stack(
[self.action_space.sample() for _ in range(batch_size)])
else:
a = self.action_space.sample()
# Convert action to torch tensor.
action = torch.from_numpy(a).to(self.device)
else:
action = action_dist.deterministic_sample()
logp = torch.zeros(
(action.size()[0], ), dtype=torch.float32, device=self.device)
return action, logp