def METHOD_NAME(self):
    """
    @brief 边与单元的邻接关系，储存与每条边相邻的两个单元的信息
    """
    nx = self.nx
    ny = self.ny
    NC = self.number_of_cells()
    NE = self.number_of_edges()
    edge2cell = np.zeros((NE, 4), dtype=self.itype)
    idx = np.arange(NC).reshape(nx, ny).T
    # x direction
    idx0 = np.arange(nx * (ny + 1), dtype=self.itype).reshape(nx, ny + 1).T
    # left element
    edge2cell[idx0[:-1], 0] = idx
    edge2cell[idx0[:-1], 2] = 0
    edge2cell[idx0[-1], 0] = idx[-1]
    edge2cell[idx0[-1], 2] = 1
    # right element
    edge2cell[idx0[1:], 1] = idx
    edge2cell[idx0[1:], 3] = 1
    edge2cell[idx0[0], 1] = idx[0]
    edge2cell[idx0[0], 3] = 0
    # y direction
    idx1 = np.arange((nx + 1) * ny, dtype=self.itype).reshape(nx + 1, ny).T
    NE0 = nx * (ny + 1)
    # left element
    edge2cell[NE0 + idx1[:, 1:], 0] = idx
    edge2cell[NE0 + idx1[:, 1:], 2] = 3
    edge2cell[NE0 + idx1[:, 0], 0] = idx[:, 0]
    edge2cell[NE0 + idx1[:, 0], 2] = 2
    # right element
    edge2cell[NE0 + idx1[:, :-1], 1] = idx
    edge2cell[NE0 + idx1[:, :-1], 3] = 2
    edge2cell[NE0 + idx1[:, -1], 1] = idx[:, -1]
    edge2cell[NE0 + idx1[:, -1], 3] = 3
    return edge2cell