def METHOD_NAME(self):
    """
    Notes
    ----
    利用最低阶混合元计算初始速度场
    """
    vdata = self.vdata
    mesh = self.mesh
    uspace = self.uspace
    uh = self.uh
    ph = self.ph
    udof = uspace.number_of_global_dofs()
    pdof = uspace.smspace.number_of_global_dofs()
    gdof = udof + pdof + 1
    M = uspace.smspace.cell_mass_matrix()
    C = M[:, 0, :].reshape(-1)
    A = uspace.stiff_matrix()
    B = uspace.div_matrix()
    F1 = uspace.source_vector(vdata.source) 
    AA = bmat([[A, -B, None], [-B.T, None, C[:, None]], [None, C, None]], format='csr')
    isBdDof = uspace.set_dirichlet_bc(uh, vdata.neumann)
    x = np.r_['0', uh, ph, 0] 
    isBdDof = np.r_['0', isBdDof, np.zeros(pdof+1, dtype=np.bool_)]
    FF = np.r_['0', np.zeros(udof, dtype=np.float64), F1, 0]
    FF -= AA@x
    bdIdx = np.zeros(gdof, dtype=np.int)
    bdIdx[isBdDof] = 1
    Tbd = spdiags(bdIdx, 0, gdof, gdof)
    T = spdiags(1-bdIdx, 0, gdof, gdof)
    AA = T@AA@T + Tbd
    FF[isBdDof] = x[isBdDof]
    x[:] = spsolve(AA, FF)
    uh[:] = x[:udof]
    ph[:] = x[udof:-1]