parameter_server.py 文件源码

def discount(self, x, gamma):
        """
        computes discounted sums along 0th dimension of x.

        inputs
        ------
        x: ndarray
        gamma: float

        outputs
        -------
        y: ndarray with same shape as x, satisfying

            y[t] = x[t] + gamma*x[t+1] + gamma^2*x[t+2] + ... + gamma^k x[t+k],
                    where k = len(x) - t - 1
        """
        x = np.array(x)
        assert x.ndim >= 1
        return lfilter([1], [1, -gamma], x[::-1], axis=0)[::-1]