115 lines
3.5 KiB
Python
115 lines
3.5 KiB
Python
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# Copyright 2017 The dm_control Authors.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ============================================================================
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"""Pendulum domain."""
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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 collections
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from dm_control import mujoco
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from dm_control.rl import control
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from local_dm_control_suite import base
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from local_dm_control_suite import common
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from dm_control.utils import containers
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from dm_control.utils import rewards
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import numpy as np
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_DEFAULT_TIME_LIMIT = 20
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_ANGLE_BOUND = 8
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_COSINE_BOUND = np.cos(np.deg2rad(_ANGLE_BOUND))
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SUITE = containers.TaggedTasks()
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def get_model_and_assets():
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"""Returns a tuple containing the model XML string and a dict of assets."""
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return common.read_model('pendulum.xml'), common.ASSETS
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@SUITE.add('benchmarking')
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def swingup(time_limit=_DEFAULT_TIME_LIMIT, random=None,
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environment_kwargs=None):
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"""Returns pendulum swingup task ."""
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physics = Physics.from_xml_string(*get_model_and_assets())
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task = SwingUp(random=random)
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environment_kwargs = environment_kwargs or {}
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return control.Environment(
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physics, task, time_limit=time_limit, **environment_kwargs)
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class Physics(mujoco.Physics):
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"""Physics simulation with additional features for the Pendulum domain."""
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def pole_vertical(self):
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"""Returns vertical (z) component of pole frame."""
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return self.named.data.xmat['pole', 'zz']
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def angular_velocity(self):
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"""Returns the angular velocity of the pole."""
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return self.named.data.qvel['hinge'].copy()
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def pole_orientation(self):
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"""Returns both horizontal and vertical components of pole frame."""
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return self.named.data.xmat['pole', ['zz', 'xz']]
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class SwingUp(base.Task):
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"""A Pendulum `Task` to swing up and balance the pole."""
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def __init__(self, random=None):
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"""Initialize an instance of `Pendulum`.
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Args:
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random: Optional, either a `numpy.random.RandomState` instance, an
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integer seed for creating a new `RandomState`, or None to select a seed
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automatically (default).
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"""
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super(SwingUp, self).__init__(random=random)
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def initialize_episode(self, physics):
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"""Sets the state of the environment at the start of each episode.
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Pole is set to a random angle between [-pi, pi).
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Args:
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physics: An instance of `Physics`.
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"""
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physics.named.data.qpos['hinge'] = self.random.uniform(-np.pi, np.pi)
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super(SwingUp, self).initialize_episode(physics)
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def get_observation(self, physics):
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"""Returns an observation.
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Observations are states concatenating pole orientation and angular velocity
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and pixels from fixed camera.
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Args:
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physics: An instance of `physics`, Pendulum physics.
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Returns:
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A `dict` of observation.
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"""
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obs = collections.OrderedDict()
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obs['orientation'] = physics.pole_orientation()
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obs['velocity'] = physics.angular_velocity()
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return obs
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def get_reward(self, physics):
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return rewards.tolerance(physics.pole_vertical(), (_COSINE_BOUND, 1))
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