62 lines
1.9 KiB
Python
62 lines
1.9 KiB
Python
import numpy as np
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from gymnasium import utils
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from gymnasium.envs.mujoco import MuJocoPyEnv
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from gymnasium.spaces import Box
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class Walker2dEnv(MuJocoPyEnv, utils.EzPickle):
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metadata = {
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"render_modes": [
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"human",
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"rgb_array",
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"depth_array",
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],
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"render_fps": 125,
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}
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def __init__(self, **kwargs):
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observation_space = Box(low=-np.inf, high=np.inf, shape=(17,), dtype=np.float64)
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MuJocoPyEnv.__init__(
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self, "walker2d.xml", 4, observation_space=observation_space, **kwargs
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)
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utils.EzPickle.__init__(self, **kwargs)
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def step(self, a):
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posbefore = self.sim.data.qpos[0]
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self.do_simulation(a, self.frame_skip)
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posafter, height, ang = self.sim.data.qpos[0:3]
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alive_bonus = 1.0
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reward = (posafter - posbefore) / self.dt
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reward += alive_bonus
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reward -= 1e-3 * np.square(a).sum()
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terminated = not (height > 0.8 and height < 2.0 and ang > -1.0 and ang < 1.0)
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ob = self._get_obs()
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if self.render_mode == "human":
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self.render()
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return ob, reward, terminated, False, {}
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def _get_obs(self):
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qpos = self.sim.data.qpos
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qvel = self.sim.data.qvel
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return np.concatenate([qpos[1:], np.clip(qvel, -10, 10)]).ravel()
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def reset_model(self):
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self.set_state(
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self.init_qpos
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+ self.np_random.uniform(low=-0.005, high=0.005, size=self.model.nq),
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self.init_qvel
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+ self.np_random.uniform(low=-0.005, high=0.005, size=self.model.nv),
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)
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return self._get_obs()
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def viewer_setup(self):
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assert self.viewer is not None
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self.viewer.cam.trackbodyid = 2
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self.viewer.cam.distance = self.model.stat.extent * 0.5
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self.viewer.cam.lookat[2] = 1.15
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self.viewer.cam.elevation = -20
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