c59ad40aef
Add class BaseNoise and GaussianNoise for the concept of exploration noise. Add new test for sac tested in MountainCarContinuous-v0, which should benefits from the two above new feature.
84 lines
2.4 KiB
Python
84 lines
2.4 KiB
Python
import numpy as np
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from typing import Union, Optional
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from abc import ABC, abstractmethod
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class BaseNoise(ABC, object):
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"""The action noise base class."""
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def __init__(self, **kwargs) -> None:
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super(BaseNoise, self).__init__()
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@abstractmethod
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def __call__(self, **kwargs) -> np.ndarray:
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"""Generate new noise."""
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raise NotImplementedError
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def reset(self, **kwargs) -> None:
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"""Reset to the initial state."""
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pass
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class GaussianNoise(BaseNoise):
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"""Class for vanilla gaussian process,
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used for exploration in DDPG by default.
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"""
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def __init__(self,
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mu: float = 0.0,
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sigma: float = 1.0):
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super().__init__()
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self._mu = mu
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assert 0 <= sigma, 'noise std should not be negative'
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self._sigma = sigma
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def __call__(self, size: tuple) -> np.ndarray:
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return np.random.normal(self._mu, self._sigma, size)
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class OUNoise(BaseNoise):
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"""Class for Ornstein-Uhlenbeck process, as used for exploration in DDPG.
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Usage:
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::
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# init
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self.noise = OUNoise()
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# generate noise
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noise = self.noise(logits.shape, eps)
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For required parameters, you can refer to the stackoverflow page. However,
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our experiment result shows that (similar to OpenAI SpinningUp) using
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vanilla gaussian process has little difference from using the
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Ornstein-Uhlenbeck process.
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"""
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def __init__(self,
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mu: float = 0.0,
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sigma: float = 0.3,
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theta: float = 0.15,
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dt: float = 1e-2,
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x0: Optional[Union[float, np.ndarray]] = None
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) -> None:
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super(BaseNoise, self).__init__()
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self._mu = mu
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self._alpha = theta * dt
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self._beta = sigma * np.sqrt(dt)
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self._x0 = x0
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self.reset()
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def __call__(self, size: tuple, mu: Optional[float] = None) -> np.ndarray:
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"""Generate new noise. Return a ``numpy.ndarray`` which size is equal
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to ``size``.
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"""
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if self._x is None or self._x.shape != size:
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self._x = 0
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if mu is None:
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mu = self._mu
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r = self._beta * np.random.normal(size=size)
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self._x = self._x + self._alpha * (mu - self._x) + r
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return self._x
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def reset(self) -> None:
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"""Reset to the initial state."""
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self._x = self._x0
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