def METHOD_NAME(self): 
    """
    @brief 生成初始网格
    """
    fd = self.domain.signed_dist_function
    fh = self.domain.sizing_function 
    box = self.domain.box
    hmin = self.hmin
    xh = box[1] - box[0]
    yh = box[3] - box[2]
    N = int(xh/hmin)+1
    M = int(yh/(hmin*np.sqrt(3)/2)) + 1
    mg = np.mgrid[box[2]:box[3]:complex(0, M), box[0]:box[1]:complex(0, N)]
    x = mg[1, :, :]
    y = mg[0, :, :]
    x[1::2, :] += hmin/2
    node = np.concatenate(
            (x.reshape(-1, 1), y.reshape((-1,1))), 
            axis=1)
    node = node[fd(node) < -self.geps, :]
    r0 = 1/fh(node)**2
    NN = len(node)
    node = node[np.random.random((NN, )) < r0/np.max(r0),:]
    fnode = self.domain.facet(0) # 区域中的固定点
    if fnode is not None:
        # TODO: 重复点的问题
        node = np.concatenate((fnode, node), axis=0)
    return node