-
Notifications
You must be signed in to change notification settings - Fork 718
/
scripted_py_policy.py
124 lines (101 loc) · 4.6 KB
/
scripted_py_policy.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
# coding=utf-8
# Copyright 2020 The TF-Agents Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Policy implementation that steps over a given configuration."""
from __future__ import absolute_import
from __future__ import division
# Using Type Annotations.
from __future__ import print_function
from typing import Sequence, Tuple
from absl import logging
import numpy as np
from tf_agents.policies import py_policy
from tf_agents.specs import array_spec
from tf_agents.trajectories import policy_step
from tf_agents.trajectories import time_step as ts
from tf_agents.typing import types
from tensorflow.python.util import nest # pylint:disable=g-direct-tensorflow-import # TF internal
class ScriptedPyPolicy(py_policy.PyPolicy):
"""Returns actions from the given configuration."""
def __init__(self, time_step_spec: ts.TimeStep,
action_spec: types.NestedArraySpec,
action_script: Sequence[Tuple[int, types.NestedArray]]):
"""Instantiates the scripted policy.
The Action script can be configured through gin. e.g:
ScriptedPyPolicy.action_script = [
(1, { "action1": [[5, 2], [1, 3]],
"action2": [[4, 6]]},),
(0, { "action1": [[8, 1], [9, 2]],
"action2": [[1, 2]]},),
(2, { "action1": [[1, 1], [3, 2]],
"action2": [[8, 2]]},),
]
In this case the first action is executed once, the second scripted action
is disabled and skipped. Then the third listed action is executed for two
steps.
Args:
time_step_spec: A time_step_spec for the policy will interact
with.
action_spec: An action_spec for the environment the policy will interact
with.
action_script: A list of 2-tuples of the form (n, nest) where the nest of
actions follow the action_spec. Each action will be executed for n
steps.
"""
if time_step_spec is None:
time_step_spec = ts.time_step_spec()
super(ScriptedPyPolicy, self).__init__(
time_step_spec=time_step_spec, action_spec=action_spec)
self._action_script = action_script
def _get_initial_state(self, batch_size):
del batch_size
# We use the state to keep track of the action index to execute and to count
# how many times it has been performed.
return [0, 0]
def _action(self, time_step, policy_state):
del time_step # Unused.
if policy_state is None:
policy_state = [0, 0]
action_index, num_repeats = policy_state # pylint: disable=unpacking-non-sequence
def _check_episode_length():
if action_index >= len(self._action_script):
raise ValueError(
"Episode is longer than the provided scripted policy. Consider "
"setting a TimeLimit wrapper that stops episodes within the length"
" of your scripted policy.")
_check_episode_length()
n, current_action = self._action_script[action_index]
# If the policy has been executed n times get the next scripted action.
# Allow users to disable entries in the scripted policy by setting n <= 0.
while num_repeats >= n:
action_index += 1
num_repeats = 0
_check_episode_length()
n, current_action = self._action_script[action_index]
num_repeats += 1
# To make it easier for the user we allow the actions in the script to be
# lists instead of numpy arrays. Checking the arrays_nest requires us to
# have the leaves be objects and not lists so we lift them into numpy
# arrays.
def actions_as_array(action_spec, action):
return np.asarray(action, dtype=action_spec.dtype)
current_action = nest.map_structure_up_to(
self._action_spec, actions_as_array, self._action_spec, current_action)
if not array_spec.check_arrays_nest(current_action, self._action_spec):
raise ValueError(
"Action at index {} does not match the environment's action_spec. "
"Got: {}. Expected {}.".format(action_index, current_action,
self._action_spec))
logging.info("Policy_state: %r", policy_state)
return policy_step.PolicyStep(current_action, [action_index, num_repeats])