def arma_impulse_response(ar, ma, nobs=100):
 impulse = np.zeros(nobs)
 impulse[0] = 1.0
 return signal.lfilter(ma, ar, impulse)

def arma_impulse_response ( ar , ma , nobs = 100 ) : impulse = np . zeros ( nobs ) impulse [ 0 ] = 1.0 return signal . lfilter ( ma , ar , impulse )
get the impulse response function for arma process parameters ma : array_like .