Files

32 lines
874 B
Python

import numpy as np
class RandomProcess(object):
def reset_states(self):
pass
class GaussianProcess(RandomProcess):
def __init__(self, size, std):
self.size = size
self.std = std
def sample(self):
return np.random.randn(*self.size) * self.std()
class OrnsteinUhlenbeckProcess(RandomProcess):
def __init__(self, size, std, theta=.15, dt=1e-2, x0=None):
self.theta = theta
self.mu = 0
self.std = std
self.dt = dt
self.x0 = x0
self.size = size
self.reset_states()
def sample(self):
x = self.x_prev + self.theta * (self.mu - self.x_prev) * self.dt + self.std() * np.sqrt(self.dt) * np.random.randn(*self.size)
self.x_prev = x
return x
def reset_states(self):
self.x_prev = self.x0 if self.x0 is not None else np.zeros(self.size)