コード例 #1
0
ファイル: HalfEdgeMeshTest.py プロジェクト: zweien/fealpy
    def triangle_mesh_test(self, plot=False):

        node = np.array([(0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0)])
        cell = np.array([(1, 2, 0), (3, 0, 2)])

        tmesh = TriangleMesh(node, cell)
        tmesh.uniform_refine(n=1)
        mesh = HalfEdgeMesh.from_mesh(tmesh)
        if plot:
            halfedge = mesh.ds.halfedge
            for i, idx in enumerate(halfedge):
                print(i, ": ", idx)

            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True)
            mesh.find_cell(axes, showindex=True)

            fig = plt.figure()
            axes = fig.gca()
            mesh.add_halfedge_plot(axes)
            mesh.find_node(axes, showindex=True)
            mesh.find_cell(axes, showindex=True)
            plt.show()
コード例 #2
0
ファイル: HalfEdgeMeshTest.py プロジェクト: zweien/fealpy
    def refine_triangle_rbTest(self, l, plot=True, rb=True):
        cell = np.array([[0, 1, 2], [0, 2, 3], [1, 4, 5], [2, 1, 5]],
                        dtype=np.int)
        node = np.array([[0, 0], [1, 0], [1, 1], [0, 1], [2, 0], [2, 1]],
                        dtype=np.float)
        mesh = TriangleMesh(node, cell)
        #mesh.uniform_refine()
        mesh = HalfEdgeMesh.from_mesh(mesh)
        mesh.ds.cell2hedge = np.array([0, 3, 2, 11, 10])
        c = np.array([0.2, 0.2])
        r = 1.2
        h = 1e-2
        k = 0
        NB = 0
        start = time.time()
        while k < l:
            halfedge = mesh.ds.halfedge
            halfedge1 = halfedge[:, 3]
            node = mesh.node
            flag = node - c
            flag = flag[:, 0]**2 + flag[:, 1]**2
            flag = flag <= r**2
            flag1 = flag[halfedge[:, 0]].astype(int)
            flag2 = flag[halfedge[halfedge1, 0]].astype(int)
            markedge = flag1 + flag2 == 1
            markedcell = halfedge[markedge, 1]
            markedcell = np.unique(markedcell)
            cell = np.unique(halfedge[:, 1])
            nc = cell.shape[0]
            markedcell1 = np.zeros(nc)
            markedcell1[markedcell] = 1
            if rb:
                mesh.refine_triangle_rb(markedcell1)
            else:
                mesh.refine_triangle_rbg(markedcell1)
            k += 1
            print('循环', k, '次***************************')
            #print('node', node)
            #print('cell',cell)
        end = time.time()
        print(end - start)
        if plot:
            fig = plt.figure()
            axes = fig.gca()
            nindex = mesh.nodedata['level']
            mesh.add_plot(axes)
            #mesh.add_halfedge_plot(axes, showindex=True)
            #mesh.find_node(axes, showindex=True, multiindex=nindex)
            plt.show()
        if 0:
            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True)
            mesh.find_cell(axes, showindex=True)

            cindex = np.arange(mesh.number_of_cells() - 1) + 1
            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True)
            mesh.find_cell(axes, showindex=True, multiindex=cindex)

            NN = mesh.number_of_nodes()
            nindex = np.zeros(NN, dtype=np.int)
            halfedge = mesh.ds.halfedge
            nindex = mesh.nodedata['level']
            cindex = mesh.get_data('cell', 'level')
            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True, multiindex=nindex)
            mesh.find_cell(axes, showindex=True, multiindex=cindex)
            plt.show()
コード例 #3
0
ファイル: HalfEdgeMeshTest.py プロジェクト: zweien/fealpy
    def voronoi_test(self, plot=False):
        from scipy.spatial import Delaunay
        from scipy.spatial import Voronoi, voronoi_plot_2d
        from scipy.spatial import KDTree

        points = np.random.rand(10, 2)
        print(points)

        # 边界点固定标记, 在网格生成与自适应算法中不能移除
        # 1: 固定
        # 0: 自由
        fflag = np.ones(4, dtype=np.bool)

        #  dflag 单元所处的子区域的标记编号
        #  0: 表示外部无界区域
        # -n: n >= 1, 表示编号为 -n 洞
        #  n: n >= 1, 表示编号为  n 的内部子区域
        dflag = np.array([1, 0])

        node = np.array([(0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0)],
                        dtype=np.float)
        halfedge = np.array([(1, 0, 1, 3, 4, 1), (2, 0, 2, 0, 5, 1),
                             (3, 0, 3, 1, 6, 1), (0, 0, 0, 2, 7, 1),
                             (0, 1, 7, 5, 0, 0), (1, 1, 4, 6, 1, 0),
                             (2, 1, 5, 7, 2, 0), (3, 1, 6, 4, 3, 0)],
                            dtype=np.int)
        NC = 1
        mesh = HalfEdgeMesh(node, halfedge, NC)
        mesh.set_data('fflag', fflag, 'node')
        mesh.set_data('dflag', dflag, 'cell')

        v = Voronoi(points)
        tree = KDTree(points)

        print("points:\n", v.points)
        print('vertices:\n', v.vertices)
        print('ridge_points:\n', v.ridge_points)
        print('ridge_vertices:\n', v.ridge_vertices)
        print('regions:\n', v.regions)
        print('point_region:\n', v.point_region)

        d, nidx = tree.query(node)
        print(nidx)

        if plot:
            halfedge = mesh.ds.halfedge
            for i, idx in enumerate(halfedge):
                print(i, ": ", idx)

            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            # mesh.find_node(axes, showindex=True, multiindex=nidx)
            mesh.find_node(axes, node=points, color='r', showindex=True)
            mesh.find_node(axes, node=v.vertices, color='b', showindex=True)
            voronoi_plot_2d(v, axes)

            fig = plt.figure()
            axes = fig.gca()
            mesh.add_halfedge_plot(axes)
            mesh.find_node(axes, showindex=True)
            mesh.find_cell(axes, showindex=True)
            plt.show()
コード例 #4
0
ファイル: HalfEdgeMeshTest.py プロジェクト: zweien/fealpy
    def refine_quad(self, plot=True):
        cell = np.array([[0, 1, 2, 3], [1, 4, 5, 2]], dtype=np.int)
        node = np.array([[0, 0], [1, 0], [1, 1], [0, 1], [2, 0], [2, 1]],
                        dtype=np.float)
        mesh = QuadrangleMesh(node, cell)
        #mesh.uniform_refine()
        mesh = HalfEdgeMesh.from_mesh(mesh)
        c = np.array([0.8, 0.8])
        r = 0.5
        h = 1e-2
        l = 6
        k = 0
        NB = 0
        while k < l:
            halfedge = mesh.ds.halfedge
            halfedge1 = halfedge[:, 3]
            node = mesh.node
            flag = node - c
            flag = flag[:, 0]**2 + flag[:, 1]**2
            flag = flag <= r**2
            flag1 = flag[halfedge[:, 0]].astype(int)
            flag2 = flag[halfedge[halfedge1, 0]].astype(int)
            markedge = flag1 + flag2 == 1
            markedcell = halfedge[markedge, 1]
            markedcell = np.unique(markedcell)
            cell = np.unique(halfedge[:, 1])
            nc = cell.shape[0]
            markedcell1 = np.zeros(nc)
            markedcell1[markedcell] = 1
            print('makee', markedcell)
            mesh.refine_quad(markedcell1)
            k += 1
            print('循环', k, '次***************************')
        if plot:
            fig = plt.figure()
            axes = fig.gca()
            nindex = mesh.nodedata['level']
            mesh.add_plot(axes)
            #mesh.add_halfedge_plot(axes, showindex=True)
            #mesh.find_node(axes, showindex=True, multiindex=nindex)
            plt.show()
        if 0:
            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True)
            mesh.find_cell(axes, showindex=True)

            cindex, = np.nonzero(mesh.ds.cflag)
            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True)
            mesh.find_cell(axes, showindex=True, multiindex=cindex)

            NN = mesh.number_of_nodes()
            nindex = np.zeros(NN, dtype=np.int)
            halfedge = mesh.ds.halfedge
            nindex = mesh.nodedata['level']
            cindex = mesh.get_data('cell', 'level')
            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True, multiindex=nindex)
            mesh.find_cell(axes, showindex=True, multiindex=cindex)
            plt.show()
コード例 #5
0
ファイル: HalfEdgeMeshTest.py プロジェクト: zweien/fealpy
    def adaptive_poly_test(self, plot=True):
        """"
        initial mesh
        """
        node = np.array([(0.0, 0.0), (0.0, 1.0), (0.0, 2.0), (1.0, 0.0),
                         (1.0, 1.0), (1.0, 2.0), (2.0, 0.0), (2.0, 1.0),
                         (2.0, 2.0)],
                        dtype=np.float)
        cell = np.array([0, 3, 4, 4, 1, 0, 1, 4, 5, 2, 3, 6, 7, 4, 4, 7, 8, 5],
                        dtype=np.int)
        cellLocation = np.array([0, 3, 6, 10, 14, 18], dtype=np.int)

        mesh = PolygonMesh(node, cell, cellLocation)
        mesh = HalfEdgeMesh.from_mesh(mesh)

        fig = plt.figure()
        axes = fig.gca()
        mesh.add_plot(axes)
        mesh.find_node(axes, showindex=True)
        mesh.find_cell(axes, showindex=True)

        NE = mesh.number_of_edges()
        nC = mesh.number_of_cells()
        """
        refined mesh
        """
        aopts = mesh.adaptive_options(method='numrefine',
                                      maxcoarsen=3,
                                      HB=True)
        eta = [0, 0, 1, 1, 1]

        mesh.adaptive(eta, aopts)
        print('r', aopts['HB'])

        fig = plt.figure()
        axes = fig.gca()
        mesh.add_plot(axes)
        mesh.find_node(axes, showindex=True)
        mesh.find_cell(axes, showindex=True)
        plt.show()

        mesh.from_mesh(mesh)
        """
        coarsened mesh
        """
        eta = [0, 0, 0, 0, 0, 0, 0, -1, 0, -1, 0, -1, 0, -1]
        #eta = [0,0,0,0,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2]

        mesh.adaptive(eta, aopts)

        fig = plt.figure()
        axes = fig.gca()
        mesh.add_plot(axes)
        mesh.find_node(axes, showindex=True)
        mesh.find_cell(axes, showindex=True)
        plt.show()

        if plot:

            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True)
            mesh.find_cell(axes, showindex=True)

            NAC = mesh.number_of_all_cells()  # 包括外部区域和洞
            cindex = range(mesh.ds.cellstart, NAC)
            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True)
            mesh.find_cell(axes, showindex=True, multiindex=cindex)

            NN = mesh.number_of_nodes()
            nindex = np.zeros(NN, dtype=np.int)
            halfedge = mesh.ds.halfedge
            nindex[halfedge[:, 0]] = mesh.get_data('halfedge', 'level')
            cindex = mesh.get_data('cell', 'level')
            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True, multiindex=nindex)
            mesh.find_cell(axes, showindex=True, multiindex=cindex)
            plt.show()
        else:
            return mesh
コード例 #6
0
ファイル: HalfEdgeMeshTest.py プロジェクト: zweien/fealpy
    def refine_poly_test(self, plot=True):
        node = np.array([(0.0, 0.0), (0.0, 1.0), (0.0, 2.0), (1.0, 0.0),
                         (1.0, 1.0), (1.0, 2.0), (2.0, 0.0), (2.0, 1.0),
                         (2.0, 2.0)],
                        dtype=np.float)
        cell = np.array([0, 3, 4, 4, 1, 0, 1, 4, 5, 2, 3, 6, 7, 4, 4, 7, 8, 5],
                        dtype=np.int)
        cellLocation = np.array([0, 3, 6, 10, 14, 18], dtype=np.int)

        mesh = PolygonMesh(node, cell, cellLocation)
        mesh = HalfEdgeMesh.from_mesh(mesh)

        fig = plt.figure()
        axes = fig.gca()
        mesh.add_plot(axes)
        mesh.find_node(axes, showindex=True)
        mesh.find_cell(axes, showindex=True)
        clevel = mesh.celldata['level']
        print(clevel)
        NE = mesh.number_of_edges()
        NC = mesh.number_of_cells()

        if True:
            isMarkedCell = mesh.mark_helper([2])
            mesh.refine_poly(isMarkedCell, dflag=False)

        if False:
            isMarkedCell = mesh.mark_helper([6])
            mesh.refine_poly(isMarkedCell, dflag=False)

        if False:
            isMarkedCell = mesh.mark_helper([3])
            mesh.refine_poly(isMarkedCell, dflag=False)

        if 1:
            isMarkedCell = mesh.mark_helper([1, 5])
            mesh.refine_poly(isMarkedCell, dflag=False)

        if False:
            isMarkedCell = mesh.mark_helper([1, 12])
            mesh.refine_poly(isMarkedCell, dflag=False)

        if False:
            isMarkedCell = mesh.mark_helper([0, 21])
            mesh.refine_poly(isMarkedCell, dflag=False)
        clevel = mesh.celldata['level']
        print(clevel)

        #print("halfedge level:\n")
        #for i, val in enumerate(mesh.halfedgedata['level']):
        #    print(i, ':', val, mesh.ds.halfedge[i, 0:2])

        #print("cell level:\n")
        #for i, val in enumerate(mesh.celldata['level']):
        #    print(i, ':', val)

        if plot:

            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True)
            mesh.find_cell(axes, showindex=True)

            NAC = mesh.number_of_all_cells()  # 包括外部区域和洞
            cindex = range(mesh.ds.cellstart, NAC)
            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True)
            mesh.add_halfedge_plot(axes, showindex=True)
            mesh.find_cell(axes, showindex=True, multiindex=cindex)

            NN = mesh.number_of_nodes()
            nindex = np.zeros(NN, dtype=np.int)
            halfedge = mesh.ds.halfedge
            nindex[halfedge[:, 0]] = mesh.get_data('halfedge', 'level')
            cindex = mesh.get_data('cell', 'level')
            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True, multiindex=nindex)
            mesh.find_cell(axes, showindex=True, multiindex=cindex)
            plt.show()
        else:
            return mesh
コード例 #7
0
    def refine_tri(self, maxit=2, method='rg', plot=True, rb=True):
        cell = np.array([[0, 1, 2], [0, 2, 3], [1, 4, 5], [2, 1, 5]],
                        dtype=np.int)
        node = np.array([[0, 0], [1, 0], [1, 1], [0, 1], [2, 0], [2, 1]],
                        dtype=np.float)

        if False:
            mesh = TriangleMesh(node, cell)
            mesh = HalfEdgeMesh.from_mesh(mesh)
            mesh.ds.cell2hedge = np.array([0, 3, 2, 11, 10])
            isMarkedCell = np.array([0, 1, 0, 0, 1], dtype=np.bool_)
            #mesh.refine_triangle_rbg(isMarkedCell)

            mesh.ds.NV = 3
            cell = mesh.ds.cell_to_node()
            node = mesh.entity('node')

            mesh = TriangleMesh(node, cell)
            mesh = HalfEdgeMesh2d.from_mesh(mesh)
            mesh.init_level_info()
            if False:
                fig = plt.figure()
                axes = fig.gca()
                mesh.add_plot(axes)
                mesh.add_halfedge_plot(axes, showindex=True)
                mesh.find_node(axes, showindex=True)
                mesh.find_cell(axes, showindex=True)
                plt.show()

            NE = mesh.ds.NE
            color = np.zeros(NE * 2, dtype=np.int_)
            if method == 'rg':
                color[[4, 13, 17, 28]] = 1
                color[[23, 27]] = 2
                color[[22, 26]] = 3
                mesh.hedgecolor = color
                isMarkedCell = np.array(
                    [0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0], dtype=np.bool_)
                mesh.refine_triangle_rg(isMarkedCell)
            else:
                color[[2, 3, 10, 11]] = 1
                mesh.hedgecolor = color
                isMarkedCell = np.array([0, 1, 1, 0, 0], dtype=np.bool_)
                #isMarkedCell = np.array([0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0 ,0],
                #       dtype=np.bool_)
                mesh.refine_triangle_nvb(isMarkedCell)
                mesh.print()
            if plot:
                fig = plt.figure()
                axes = fig.gca()
                mesh.add_plot(axes)
                mesh.add_halfedge_plot(axes, showindex=True)
                mesh.find_node(axes, showindex=True)
                mesh.find_cell(axes, showindex=True)
                plt.show()
        if True:
            mesh = TriangleMesh(node, cell)
            mesh = HalfEdgeMesh2d.from_mesh(mesh)
            mesh.init_level_info()
            NE = mesh.ds.NE
            color = np.zeros(NE * 2, dtype=np.int_)
            if method == 'nvb':
                color[[2, 3, 10, 11]] = 1
            mesh.hedgecolor = color
            c = np.array([0.8, 0.8])
            r = 0.9
            h = 1e-2
            k = 0
            NB = 0
            start = time.time()
            while k < maxit:
                halfedge = mesh.ds.halfedge
                halfedge1 = halfedge[:, 3]
                node = mesh.node
                flag = node - c
                flag = flag[:, 0]**2 + flag[:, 1]**2
                flag = flag <= r**2
                flag1 = flag[halfedge[:, 0]].astype(int)
                flag2 = flag[halfedge[halfedge1, 0]].astype(int)
                markedge = flag1 + flag2 == 1
                markedcell = halfedge[markedge, 1]
                markedcell = np.unique(markedcell)
                cell = np.unique(halfedge[:, 1])
                nc = cell.shape[0]
                markedcell1 = np.zeros(nc)
                markedcell1[markedcell] = 1
                if method == 'rg':
                    mesh.refine_triangle_rg(markedcell1.astype(np.bool_))
                else:
                    mesh.refine_triangle_nvb(markedcell1.astype(np.bool_))
                k += 1
                print('循环', k, '次***************************')
            end = time.time()
            print('用时', end - start)
            if plot:
                fig = plt.figure()
                axes = fig.gca()
                nindex = mesh.nodedata['level']
                mesh.add_plot(axes)
                #mesh.add_halfedge_plot(axes, showindex=True)
                #mesh.find_node(axes, showindex=True, multiindex=nindex)
                #mesh.find_cell(axes, showindex=True)
                #print(np.c_[np.arange(len(mesh.hedgecolor)), mesh.hedgecolor])
                plt.show()
コード例 #8
0
    def run(self, estimator='mix'):
        model = problem['objective']
        mesh = problem['mesh']
        mesh = HalfEdgeMesh.from_mesh(mesh)

        fig = plt.figure()
        axes = fig.gca()
        mesh.add_plot(axes)
        mesh.find_node(axes, showindex=True)
        mesh.find_cell(axes, showindex=True)

        aopts = mesh.adaptive_options(method='numrefine',
                                      maxcoarsen=3,
                                      HB=True)
        while True:
            while True:
                print('NN', mesh.number_of_nodes())
                NC = mesh.number_of_cells()

                mu = problem['x0']
                w = np.zeros(mu.shape)
                w[:, 0] = mu[:, 0] - mu[:, 1]
                w[:, 1] = mu[:, 0] + mu[:, 1]

                if estimator == 'mix':
                    #eta = model.mix_estimate(q,w=1)
                    eta = np.ones(NC, dtype=int)
                if estimator == 'grad':
                    eta = model.estimate(q)

                aopts['data'] = {'mu': mu}
                S0 = model.vemspace.project_to_smspace(aopts['data']['mu'][:,
                                                                           0])
                S1 = model.vemspace.project_to_smspace(aopts['data']['mu'][:,
                                                                           1])

                mesh.adaptive(eta, aopts)

                fig = plt.figure()
                axes = fig.gca()
                mesh.add_plot(axes)
                mesh.find_node(axes, showindex=True)
                mesh.find_cell(axes, showindex=True)

                model.reinit(mesh)
                aopts['data']['mu'] = np.zeros((model.gdof, 2))
                aopts['data']['mu'][:, 0] = model.vemspace.interpolation(
                    S0, aopts['HB'])
                aopts['data']['mu'][:, 1] = model.vemspace.interpolation(
                    S1, aopts['HB'])
                problem['x0'] = aopts['data']['mu']

                optalg = SteepestDescentAlg(problem, options)
                x, f, g, diff = optalg.run()
                problem['mesh'] = mesh
                problem['x0'] = x
                q = model.rho.copy()
                q[:, 0] = model.q0[:, -1]
                q[:, 1] = model.q1[:, -1]

                if diff < options['FunValDiff']:
                    if (np.max(problem['rho'][:, 0]) < 1) and (np.min(
                            problem['rho'][:, 0]) > 0):
                        break
                pass
コード例 #9
0
    def refine_test(self, plot=True):
        node = np.array([(0.0, 0.0), (0.0, 1.0), (0.0, 2.0), (1.0, 0.0),
                         (1.0, 1.0), (1.0, 2.0), (2.0, 0.0), (2.0, 1.0),
                         (2.0, 2.0)],
                        dtype=np.float)
        cell = np.array([0, 3, 4, 4, 1, 0, 1, 4, 5, 2, 3, 6, 7, 4, 4, 7, 8, 5],
                        dtype=np.int)
        cellLocation = np.array([0, 3, 6, 10, 14, 18], dtype=np.int)

        mesh = PolygonMesh(node, cell, cellLocation)
        mesh = HalfEdgeMesh.from_polygonmesh(mesh)

        NE = mesh.number_of_edges()
        NC = mesh.number_of_cells()

        if True:
            isMarkedCell = np.zeros(NC + 1, dtype=np.bool)
            isMarkedCell[2] = True
            mesh.refine(isMarkedCell, dflag=False)

        if True:
            NC = mesh.number_of_cells()
            isMarkedCell = np.zeros(NC + 1, dtype=np.bool)
            isMarkedCell[6] = True
            mesh.refine(isMarkedCell, dflag=False)

        if True:
            NC = mesh.number_of_cells()
            isMarkedCell = np.zeros(NC + 1, dtype=np.bool)
            isMarkedCell[3] = True
            mesh.refine(isMarkedCell, dflag=False)

        if True:
            NC = mesh.number_of_cells()
            isMarkedCell = np.zeros(NC + 1, dtype=np.bool)
            isMarkedCell[1] = True
            isMarkedCell[5] = True
            mesh.refine(isMarkedCell, dflag=False)

        if True:
            NC = mesh.number_of_cells()
            isMarkedCell = np.zeros(NC + 1, dtype=np.bool)
            isMarkedCell[1] = True
            isMarkedCell[12] = True
            mesh.refine(isMarkedCell, dflag=False)

        if True:
            NC = mesh.number_of_cells()
            isMarkedCell = np.zeros(NC + 1, dtype=np.bool)
            isMarkedCell[0] = True
            isMarkedCell[21] = True
            mesh.refine(isMarkedCell, dflag=False)

        print("halfedge level:\n")
        for i, val in enumerate(mesh.halfedgedata['level']):
            print(i, ':', val, mesh.ds.halfedge[i, 0:2])

        print("cell level:\n")
        for i, val in enumerate(mesh.celldata['level']):
            print(i, ':', val)

        if plot:
            fig = plt.figure()
            axes = fig.gca()
            mesh.add_plot(axes)
            mesh.find_node(axes, showindex=True)
            #mesh.find_edge(axes, showindex=True)
            mesh.find_cell(axes, showindex=True)
            plt.show()