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@RedTachyon
Latest commit d199778 Sep 25, 2021 History
* Pendulum env updates

Simplify the math a bit (no difference in behavior)

* Reorder the clipping of angular velocity

* Bump version of Pendulum

* black

* Update mentions of Pendulum-v0 to Pendulum-v1.
15 contributors

Users who have contributed to this file

@gdb @zuoxingdong @jkterry1 @joshmarlow @RedTachyon @instance01 @marload @olegklimov @osigaud @Olimoyo @joschu @ishmandoo
import gym
from gym import spaces
from gym.utils import seeding
import numpy as np
from os import path
class PendulumEnv(gym.Env):
metadata = {"render.modes": ["human", "rgb_array"], "video.frames_per_second": 30}
def __init__(self, g=10.0):
self.max_speed = 8
self.max_torque = 2.0
self.dt = 0.05
self.g = g
self.m = 1.0
self.l = 1.0
self.viewer = None
high = np.array([1.0, 1.0, self.max_speed], dtype=np.float32)
self.action_space = spaces.Box(
low=-self.max_torque, high=self.max_torque, shape=(1,), dtype=np.float32
)
self.observation_space = spaces.Box(low=-high, high=high, dtype=np.float32)
self.seed()
def seed(self, seed=None):
self.np_random, seed = seeding.np_random(seed)
return [seed]
def step(self, u):
th, thdot = self.state # th := theta
g = self.g
m = self.m
l = self.l
dt = self.dt
u = np.clip(u, -self.max_torque, self.max_torque)[0]
self.last_u = u # for rendering
costs = angle_normalize(th) ** 2 + 0.1 * thdot ** 2 + 0.001 * (u ** 2)
newthdot = thdot + (3 * g / (2 * l) * np.sin(th) + 3.0 / (m * l ** 2) * u) * dt
newthdot = np.clip(newthdot, -self.max_speed, self.max_speed)
newth = th + newthdot * dt
self.state = np.array([newth, newthdot])
return self._get_obs(), -costs, False, {}
def reset(self):
high = np.array([np.pi, 1])
self.state = self.np_random.uniform(low=-high, high=high)
self.last_u = None
return self._get_obs()
def _get_obs(self):
theta, thetadot = self.state
return np.array([np.cos(theta), np.sin(theta), thetadot], dtype=np.float32)
def render(self, mode="human"):
if self.viewer is None:
from gym.envs.classic_control import rendering
self.viewer = rendering.Viewer(500, 500)
self.viewer.set_bounds(-2.2, 2.2, -2.2, 2.2)
rod = rendering.make_capsule(1, 0.2)
rod.set_color(0.8, 0.3, 0.3)
self.pole_transform = rendering.Transform()
rod.add_attr(self.pole_transform)
self.viewer.add_geom(rod)
axle = rendering.make_circle(0.05)
axle.set_color(0, 0, 0)
self.viewer.add_geom(axle)
fname = path.join(path.dirname(__file__), "assets/clockwise.png")
self.img = rendering.Image(fname, 1.0, 1.0)
self.imgtrans = rendering.Transform()
self.img.add_attr(self.imgtrans)
self.viewer.add_onetime(self.img)
self.pole_transform.set_rotation(self.state[0] + np.pi / 2)
if self.last_u is not None:
self.imgtrans.scale = (-self.last_u / 2, np.abs(self.last_u) / 2)
return self.viewer.render(return_rgb_array=mode == "rgb_array")
def close(self):
if self.viewer:
self.viewer.close()
self.viewer = None
def angle_normalize(x):
return ((x + np.pi) % (2 * np.pi)) - np.pi