Python: How can I stop my function values from changing after my first call (time series)

Question

I have:

np.random.seed(123)
def v_t(var_v, T):
    v_t_ = np.zeros([T,1])
    v_t_[1:T] = (var_v ** 0.5) * np.random.randn(len(v_t_) - 1, 1)
    return v_t_

def s_t(rho, T):
    v_t_ = v_t(var_v, T)
    s_t_ = np.zeros([T,1])
    s_t_[0] = 0
    for t in range(1,T):
        s_t_[t] = rho *s_t_[t-1] + v_t_[t]
    return s_t_

However every time I call one of the values, ie

s_t(rho, T)       "or"         v_t(var_v, T)

the right value is shown. But directly afterwards, when I call the other value, the value is wrong. (Probably due to some time series effect.) After I clear my namespace, when I call the functions in the mirrored sequence, the same holds true. How do I get the right values displayed for every call without resetting the namespace???

Would be great to hear from you! Cheers, Tobias

Answer 1

我认为问题与np.random.randn（len（v_t_）-1，1）有关...