def full_y(self, Y):
        """Add self(shunt) into full Jacobian Y"""
        if not self.n:
            return
        Ysh = matrix(self.g,
                     (self.n, 1), 'd') + 1j * matrix(self.b, (self.n, 1), 'd')
        uYsh = mul(self.u, Ysh)
        Y += spmatrix(uYsh, self.a, self.a, Y.size, 'z')
Add self(shunt) into full Jacobian Y