'Analyze structural impulse responses to shocks in system
Parameters
periods : int
Returns
irf : IRAnalysis'

def irf(self, periods=10, var_order=None):

    A = self.A
    B = self.B
    P = np.dot(npl.inv(A), B)
    return IRAnalysis(self, P=P, periods=periods, svar=True)
