utils.py 文件源码

def discount_rewards(x, gamma):
    """
    Given vector x, computes a vector y such that
    y[i] = x[i] + gamma * x[i+1] + gamma^2 x[i+2] + ...
    """
    return signal.lfilter([1], [1, -gamma], x[::-1], axis=0)[::-1]

# Source: http://stackoverflow.com/a/12201744/1735784