def METHOD_NAME(self, q=3):
    integrator = self.integrator(q)
    bcs, ws = integrator.quadpts, integrator.weights
    Jp, _ = self.jacobi_matrix(bcs)
    n = np.cross(Jp[..., 0, :], Jp[..., 1, :], axis=-1)
    l = np.sqrt(np.sum(n**2, axis=-1))
    a = np.einsum('i, ij->j', ws, l)/2.0
    return a