'Compute Structural MA coefficient matrices using MLE
of A, B'

def svar_ma_rep(self, maxn=10, P=None):

    if (P is None):
        A_solve = self.A_solve
        B_solve = self.B_solve
        P = np.dot(npl.inv(A_solve), B_solve)
    ma_mats = self.ma_rep(maxn=maxn)
    return mat([np.dot(coefs, P) for coefs in ma_mats])
