Exemple #1
0
class TestMesh(TestCase):
    def setUp(self):
        self.testmesh = Mesh(dimension=2)
        nodes = np.array([[0.0, 0.0], [1.0, 0.0], [1.0, 1.0], [0.0, 1.0],
                          [2.0, 0.0], [2.0, 1.0]],
                         dtype=np.float)
        connectivity = [
            np.array([5, 6, 3], dtype=np.int),
            np.array([3, 2, 5], dtype=np.int),
            np.array([1, 2, 3, 4], dtype=np.int),
            # boundary elements
            np.array([4, 1], dtype=np.int),
            np.array([5, 6], dtype=np.int)
        ]

        shapes = ['Tri3', 'Tri3', 'Quad4', 'straight_line', 'straight_line']

        data = {
            'shape': shapes,
            'is_boundary': [False, False, False, True, True],
            'connectivity': connectivity
        }
        indices = [1, 2, 3, 4, 5]

        el_df = pd.DataFrame(data, index=indices)

        x = nodes[:, 0]
        y = nodes[:, 1]
        nodeids = [1, 2, 3, 4, 5, 6]
        self._nodeids = nodeids
        self._nodes = nodes
        self._eleids = indices
        self._connectivity = connectivity
        self._connectivity = connectivity
        self._shapes = shapes
        nodes_df = pd.DataFrame({'x': x, 'y': y}, index=nodeids)

        groups = {
            'left': {
                'elements': [3],
                'nodes': []
            },
            'right': {
                'elements': [1, 2],
                'nodes': [2, 3, 5, 6]
            },
            'left_boundary': {
                'elements': [4],
                'nodes': []
            },
            'right_boundary': {
                'elements': [5],
                'nodes': [1, 2]
            }
        }

        self.testmesh.nodes_df = nodes_df
        self.testmesh.groups = groups
        self.testmesh._el_df = el_df

        self.testmesh3d = deepcopy(self.testmesh)
        nodes3d = np.array([[0.0, 0.0, 0.0], [1.0, 0.0, 0.0], [1.0, 1.0, 0.0],
                            [0.0, 1.0, 0.0], [2.0, 0.0, 1.0], [2.0, 1.0, 1.0]],
                           dtype=np.float)
        self.testmesh3d.dimension = 3
        x = nodes3d[:, 0]
        y = nodes3d[:, 1]
        z = nodes3d[:, 2]
        nodes_df3d = pd.DataFrame({'x': x, 'y': y, 'z': z}, index=nodeids)
        self.testmesh3d.nodes_df = nodes_df3d

    def tearDown(self):
        pass

    def test_constructor(self):
        from amfe.mesh import Mesh
        mesh = Mesh(dimension=2)
        self.assertEqual(mesh.dimension, 2)
        mesh = Mesh(dimension=3)
        self.assertEqual(mesh.dimension, 3)
        with self.assertRaises(ValueError) as err:
            mesh = Mesh(dimension=1)

    def test_element_ids(self):
        assert_array_equal(self.testmesh.element_ids, self._eleids)

    def test_no_of_properties(self):
        self.assertEqual(self.testmesh.no_of_nodes, 6)
        self.assertEqual(self.testmesh.no_of_elements, 3)
        self.assertEqual(self.testmesh.no_of_boundary_elements, 2)
        self.assertEqual(self.testmesh.dimension, 2)

    def test_nodes_voigt(self):
        desired = np.array(
            [0.0, 0.0, 1.0, 0.0, 1.0, 1.0, 0.0, 1.0, 2.0, 0.0, 2.0, 1.0],
            dtype=np.float)
        assert_equal(self.testmesh.nodes_voigt, desired)

    def test_connectivity(self):
        desireds = np.array(self._connectivity)
        actuals = self.testmesh.connectivity
        for actual, desired in zip(actuals, desireds):
            assert_array_equal(actual, desired)

    def test_create_group(self):
        elementids = [1, 4, 6, 8]
        nodeids = np.array([100, 400], dtype=int)
        desired = {'elements': [1, 4, 6, 8], 'nodes': [100, 400]}
        self.testmesh.create_group('mygroup', nodeids, elementids)
        actual_nodes = set(self.testmesh.groups['mygroup']['nodes'])
        desired_nodes = set(desired['nodes'])
        actual_elements = set(self.testmesh.groups['mygroup']['elements'])
        desired_elements = set(desired['elements'])
        self.assertEqual(actual_nodes, desired_nodes)
        self.assertEqual(actual_elements, desired_elements)

        with self.assertRaises(ValueError):
            self.testmesh.create_group('right', nodeids, elementids)

        self.testmesh.create_group('mygroup2', elementids=(4, 8, 1, 6))
        actual_nodes = set(self.testmesh.groups['mygroup2']['nodes'])
        desired_nodes = set()
        actual_elements = set(self.testmesh.groups['mygroup2']['elements'])
        desired_elements = set(desired['elements'])
        self.assertEqual(actual_nodes, desired_nodes)
        self.assertEqual(actual_elements, desired_elements)

    def test_get_connectivity_by_elementids(self):
        desireds = [
            np.array([5, 6, 3], dtype=int),
            np.array([4, 1], dtype=int)
        ]
        for actual, desired in zip(
                self.testmesh.get_connectivity_by_elementids([1, 4]),
                desireds):
            assert_array_equal(actual, desired)

    def test_get_elementidxs_by_group(self):
        actual = self.testmesh.get_elementidxs_by_groups(['right'])
        desired = np.array([0, 1], dtype=int)
        assert_array_equal(actual, desired)

    def test_get_elementidxs_by_elementids(self):
        actual = self.testmesh.get_elementidxs_by_elementids([4, 1])
        desired = np.array([3, 0], dtype=int)
        assert_array_equal(actual, desired)

    def test_get_elementids_by_elementidxs(self):
        actual = self.testmesh.get_elementids_by_elementidxs([3, 0])
        desired = np.array([4, 1], dtype=int)
        assert_array_equal(actual, desired)

    def test_get_elementids_by_nodeids(self):
        actual = self.testmesh.get_elementids_by_nodeids([1])
        desired = np.array([3, 4], dtype=int)
        assert_array_equal(actual, desired)
        actual = self.testmesh.get_elementids_by_nodeids([3, 1])
        desired = np.array([1, 2, 3, 4], dtype=int)
        assert_array_equal(actual, desired)
        actual = self.testmesh.get_elementids_by_nodeids((3, 1))
        assert_array_equal(actual, desired)
        actual = self.testmesh.get_elementids_by_nodeids(np.array([3, 1]))
        assert_array_equal(actual, desired)
        actual = self.testmesh.get_elementids_by_nodeids([0])
        desired = np.array([], dtype=int)
        assert_array_equal(actual, desired)

    def test_get_elementidxs_by_groups(self):
        actual = self.testmesh.get_elementidxs_by_groups(
            ['right', 'left_boundary'])
        desired = np.array([0, 1, 3], dtype=int)
        assert_array_equal(actual, desired)

    def test_get_elementids_by_groups(self):
        actual = self.testmesh.get_elementids_by_groups(
            ['right', 'left_boundary'])
        desired = np.array([1, 2, 4], dtype=int)
        assert_array_equal(actual, desired)

        with self.assertRaises(ValueError):
            self.testmesh.get_elementids_by_groups(['wrong'])

    def test_get_nodeid_by_coordinates(self):
        # 2d case
        x, y = 2.0, 0.0
        desired = 5
        actual = self.testmesh.get_nodeid_by_coordinates(x, y)
        self.assertEqual(actual, desired)

        # 3d Case
        z = 1.0
        actual = self.testmesh3d.get_nodeid_by_coordinates(x, y, z)
        self.assertEqual(actual, desired)

        # big tolerance
        x = 500.0
        epsilon = np.inf
        actual = self.testmesh.get_nodeid_by_coordinates(x, y, epsilon=epsilon)
        self.assertEqual(actual, desired)

        actual = self.testmesh3d.get_nodeid_by_coordinates(x,
                                                           y,
                                                           z,
                                                           epsilon=epsilon)
        self.assertEqual(actual, desired)

        # zero return
        x = 500.0
        desired = None
        actual = self.testmesh.get_nodeid_by_coordinates(x, y)
        self.assertEqual(actual, desired)

        actual = self.testmesh3d.get_nodeid_by_coordinates(x, y, z)
        self.assertEqual(actual, desired)

    def test_get_nodeids_by_x_coordinates(self):
        x = 2.0
        epsilon = 0.1
        desired = {5, 6}
        actual = set(self.testmesh.get_nodeids_by_x_coordinates(x, epsilon))
        self.assertEqual(actual, desired)

        epsilon = 1.1
        desired = {2, 3, 5, 6}
        actual = set(self.testmesh.get_nodeids_by_x_coordinates(x, epsilon))
        self.assertEqual(actual, desired)

    def test_get_nodeids_by_lesser_equal_x_coordinates(self):
        x = 1.0
        epsilon = 0.1
        desired = {1, 2, 3, 4}
        actual = set(
            self.testmesh.get_nodeids_by_lesser_equal_x_coordinates(
                x, epsilon))
        self.assertEqual(actual, desired)

        x = 0.9
        actual = set(
            self.testmesh.get_nodeids_by_lesser_equal_x_coordinates(
                x, epsilon))
        self.assertEqual(actual, desired)

        epsilon = 0.01
        desired = {1, 4}
        actual = set(
            self.testmesh.get_nodeids_by_lesser_equal_x_coordinates(
                x, epsilon))
        self.assertEqual(actual, desired)

    def test_get_nodeids_by_greater_equal_x_coordinates(self):
        x = 1.0
        epsilon = 0.1
        desired = {2, 3, 5, 6}
        actual = set(
            self.testmesh.get_nodeids_by_greater_equal_x_coordinates(
                x, epsilon))
        self.assertEqual(actual, desired)

        x = 1.1
        actual = set(
            self.testmesh.get_nodeids_by_greater_equal_x_coordinates(
                x, epsilon))
        self.assertEqual(actual, desired)

        epsilon = 0.01
        desired = {5, 6}
        actual = set(
            self.testmesh.get_nodeids_by_greater_equal_x_coordinates(
                x, epsilon))
        self.assertEqual(actual, desired)

    def test_get_nodeids_by_group(self):
        actual = self.testmesh.get_nodeids_by_groups(['left'])
        desired = np.array([1, 2, 3, 4], dtype=np.int)
        assert_equal(actual, desired)
        actual = set(self.testmesh.get_nodeids_by_groups(['right_boundary']))
        desired = set(np.array([1, 2, 5, 6]))
        assert_equal(actual, desired)
        actual = set(self.testmesh.get_nodeids_by_groups(['left_boundary']))
        desired = set(np.array([1, 4], dtype=int))
        assert_equal(actual, desired)

    def test_get_ele_shapes_by_idxs(self):
        actual = self.testmesh.get_ele_shapes_by_elementidxs([1, 4, 2])
        desired = np.array(['Tri3', 'straight_line', 'Quad4'], dtype=object)
        assert_equal(actual, desired)

    def test_get_ele_shapes_by_ids(self):
        actual = self.testmesh.get_ele_shapes_by_ids([2, 5, 3])
        desired = np.array(['Tri3', 'straight_line', 'Quad4'], dtype=object)
        assert_equal(actual, desired)

    def test_get_nodeidxs_by_all(self):
        actual = self.testmesh.get_nodeidxs_by_all()
        desired = np.array([0, 1, 2, 3, 4, 5], dtype=np.int)
        assert_equal(actual, desired)

    def test_get_nodeidxs_by_nodeids(self):
        actual = self.testmesh.get_nodeidxs_by_nodeids(np.array([1, 2, 5, 6]))
        desired = np.array([0, 1, 4, 5])
        assert_equal(actual, desired)

    def test_get_nodeids_by_nodeidxs(self):
        actual = self.testmesh.get_nodeids_by_nodeidxs([3, 5, 2])
        desired = [4, 6, 3]
        assert_equal(actual, desired)
        actual = self.testmesh.get_nodeids_by_nodeidxs([3])
        desired = [4]
        assert_equal(actual, desired)

    def test_get_nodeids_by_elementids(self):
        actual = self.testmesh.get_nodeids_by_elementids(
            np.array([2, 3], dtype=int))
        desired = np.array([1, 2, 3, 4, 5], dtype=int)
        assert_array_equal(actual, desired)

        # test zero list:
        actual = self.testmesh.get_nodeids_by_elementids(
            np.array([], dtype=int))
        desired = np.array([], dtype=int)
        assert_array_equal(actual, desired)

    def test_insert_tag(self):
        current_col_num = len(self.testmesh.el_df.columns)
        tag_to_add = 'partition_id'
        self.testmesh.insert_tag(tag_to_add)
        new_col_num = len(self.testmesh.el_df.columns)
        assert_equal(current_col_num + 1, new_col_num)
        self.assertTrue(tag_to_add in self.testmesh.el_df.columns)

    def test_remove_tag(self):
        tag_name = self.testmesh.el_df.columns[1]
        current_col_num = len(self.testmesh.el_df.columns)
        self.testmesh.remove_tag(tag_name)
        new_col_num = len(self.testmesh.el_df.columns)
        assert_equal(current_col_num, new_col_num + 1)
        self.assertFalse(tag_name in self.testmesh.el_df.columns)

    def test_change_tag_values_by_dict(self):
        desired_list_1 = [4, 5]
        desired_list_2 = [1, 2, 3]
        tag_value_dict = {}
        tag_value_dict['False'] = desired_list_1
        tag_value_dict['True'] = desired_list_2
        self.testmesh._change_tag_values_by_dict('is_boundary', tag_value_dict)
        actual_list_1 = self.testmesh.el_df[self.testmesh.el_df['is_boundary']
                                            == 'False'].index.tolist()
        actual_list_2 = self.testmesh.el_df[self.testmesh.el_df['is_boundary']
                                            == 'True'].index.tolist()
        assert_equal(actual_list_1, desired_list_1)
        assert_equal(actual_list_2, desired_list_2)

    def test_replace_tag_values(self):
        current_key = 'Tri3'
        new_key = 'Tri6'
        tag_name = 'shape'
        desired = [1, 2]
        self.testmesh.replace_tag_values(tag_name, current_key, new_key)
        actual = self.testmesh.el_df[self.testmesh.el_df[tag_name] ==
                                     new_key].index.tolist()
        assert_equal(desired, actual)

    def test_get_elementids_by_tags(self):
        desired = np.array([1, 2], dtype=int)
        actual = self.testmesh.get_elementids_by_tags(['shape', 'is_boundary'],
                                                      ['Tri3', False])
        assert_array_equal(desired, actual)

    def test_get_nodeids_by_tag(self):
        desired = np.array([1, 4, 5, 6], dtype=int)
        actual = self.testmesh.get_nodeids_by_tags('shape', 'straight_line')
        assert_array_equal(desired, actual)

    def test_get_elementidxs_by_tags(self):
        desired = np.array([0, 1], dtype=int)
        actual = self.testmesh.get_elementidxs_by_tags('shape', 'Tri3')
        assert_equal(desired, actual)

    def test_get_iconnectivity_by_elementids(self):
        desired = np.array([
            np.array([0, 1, 2, 3], dtype=int),
            np.array([4, 5, 2], dtype=int)
        ])
        actual = self.testmesh.get_iconnectivity_by_elementids(
            np.array([3, 1], dtype=int))
        for actual_arr, desired_arr in zip(actual, desired):
            assert_array_equal(desired_arr, actual_arr)

        # Ask a second time to test lazy evaluation:
        actual = self.testmesh.get_iconnectivity_by_elementids(
            np.array([3, 1], dtype=int))
        for actual_arr, desired_arr in zip(actual, desired):
            assert_array_equal(desired_arr, actual_arr)

    def test_get_groups_by_elementids(self):
        groups_actual = self.testmesh.get_groups_by_elementids([1, 2, 4])
        groups_desired = ['right', 'left_boundary']

        assert_equal(groups_actual, groups_desired)

        self.testmesh.groups = {
            'left': {
                'elements': [3],
                'nodes': []
            },
            'right': {
                'elements': [1, 2],
                'nodes': [2, 3, 5, 6]
            },
            'left_boundary': {
                'elements': [4],
                'nodes': []
            },
            'right_boundary': {
                'elements': [5, 2],
                'nodes': [1, 2]
            }
        }

        groups_actual = self.testmesh.get_groups_by_elementids([1, 2, 4])
        groups_desired = ['right', 'left_boundary', 'right_boundary']

        assert_equal(groups_actual, groups_desired)

    def test_get_groups_by_nodeids(self):
        groups_actual = self.testmesh.get_groups_by_nodeids([1, 2, 6])
        groups_desired = ['right', 'right_boundary']

        assert_equal(groups_actual, groups_desired)

    def test_get_groups_dict_by_elementids(self):
        groups_actual = self.testmesh.get_groups_dict_by_elementids([1, 2, 4])
        groups_desired = {
            'right': {
                'elements': [1, 2]
            },
            'left_boundary': {
                'elements': [4]
            }
        }

        assert_equal(groups_actual, groups_desired)

        self.testmesh.groups = {
            'left': {
                'elements': [3],
                'nodes': []
            },
            'right': {
                'elements': [1, 2],
                'nodes': [2, 3, 5, 6]
            },
            'left_boundary': {
                'elements': [4],
                'nodes': []
            },
            'right_boundary': {
                'elements': [5, 2],
                'nodes': [1, 2]
            }
        }

        groups_actual = self.testmesh.get_groups_dict_by_elementids([1, 2, 4])
        groups_desired = {
            'right': {
                'elements': [1, 2]
            },
            'left_boundary': {
                'elements': [4]
            },
            'right_boundary': {
                'elements': [2]
            }
        }

        assert_equal(groups_actual, groups_desired)

    def test_get_groups_dict_by_nodeids(self):
        groups_actual = self.testmesh.get_groups_dict_by_nodeids([1, 2, 6])
        groups_desired = {
            'right': {
                'nodes': [2, 6]
            },
            'right_boundary': {
                'nodes': [1, 2]
            }
        }

        assert_equal(groups_actual, groups_desired)

    def test_merge_into_groups(self):
        add_groups = {
            'left': {
                'elements': [3],
                'nodes': [1, 4]
            },
            'right': {
                'elements': [1, 2]
            },
            'left_boundary': {
                'elements': [4],
                'nodes': []
            },
            'right_boundary': {
                'elements': [5, 2],
                'nodes': []
            },
            'new_node_group': {
                'nodes': [1, 2, 3, 4]
            }
        }

        self.testmesh.merge_into_groups(add_groups)
        groups_desired = {
            'left': {
                'elements': [3],
                'nodes': [1, 4]
            },
            'right': {
                'elements': [1, 2],
                'nodes': [2, 3, 5, 6]
            },
            'left_boundary': {
                'elements': [4],
                'nodes': []
            },
            'right_boundary': {
                'elements': [5, 2],
                'nodes': [1, 2]
            },
            'new_node_group': {
                'elements': [],
                'nodes': [1, 2, 3, 4]
            }
        }

        for group_desired in groups_desired:
            for secondary_group in ['elements', 'nodes']:
                assert_equal(
                    set(self.testmesh.groups[group_desired][secondary_group]),
                    set(groups_desired[group_desired][secondary_group]))
        self.assertEqual(len(self.testmesh.groups), len(groups_desired))

    def test_add_node(self):
        # Test 3D mesh
        mesh = Mesh(3)

        # test with tuple
        coords = (0.0, 1.0, 2.0)
        new_id = mesh.add_node(coords)
        coords_actual = mesh.nodes_df.loc[new_id, ['x', 'y', 'z']]
        assert_array_equal(coords_actual, np.array(coords, dtype=float))

        # test with array
        coords = np.array([5, 6, 3], dtype=float)
        new_id = mesh.add_node(coords)
        coords_actual = mesh.nodes_df.loc[new_id, ['x', 'y', 'z']]
        assert_array_equal(coords_actual, np.array(coords, dtype=float))

        # test with dict and id
        coords = {'x': 5.0, 'y': 6.0, 'z': 3}
        new_id = mesh.add_node(coords, 8)
        coords_actual = mesh.nodes_df.loc[new_id, ['x', 'y', 'z']]
        assert_array_equal(coords_actual, np.array([5, 6, 3], dtype=float))
        self.assertEqual(new_id, 8)

        # test raise error no overwrite
        coords = np.array([10, 4, 2], dtype=float)
        with self.assertRaises(ValueError):
            new_id = mesh.add_node(coords, 8)

        # test overwrite and with int array
        coords = np.array([10, 4, 2], dtype=int)
        new_id = mesh.add_node(coords, 8, overwrite=True)
        coords_actual = mesh.nodes_df.loc[new_id, ['x', 'y', 'z']]
        assert_array_equal(coords_actual, np.array(coords, dtype=float))
        self.assertEqual(new_id, 8)

        # Test 2D mesh
        mesh = Mesh(2)

        # test with tuple
        coords = (0.0, 1.0, 2.0)
        new_id = mesh.add_node(coords)
        coords_actual = mesh.nodes_df.loc[new_id, ['x', 'y']]
        assert_array_equal(coords_actual, np.array(coords[0:2], dtype=float))

        # test with array
        coords = np.array([5, 6, 3], dtype=float)
        new_id = mesh.add_node(coords)
        coords_actual = mesh.nodes_df.loc[new_id, ['x', 'y']]
        assert_array_equal(coords_actual, np.array(coords[0:2], dtype=float))

        # test with dict and id
        coords = {'x': 5.0, 'y': 6.0, 'z': 3}
        new_id = mesh.add_node(coords, 8)
        coords_actual = mesh.nodes_df.loc[new_id, ['x', 'y']]
        assert_array_equal(coords_actual, np.array([5, 6], dtype=float))
        self.assertEqual(new_id, 8)

        # test raise error no overwrite
        coords = np.array([10, 4, 2], dtype=float)
        with self.assertRaises(ValueError):
            new_id = mesh.add_node(coords, 8)

        # test overwrite and with int array
        coords = np.array([10, 4, 2], dtype=int)
        new_id = mesh.add_node(coords, 8, overwrite=True)
        coords_actual = mesh.nodes_df.loc[new_id, ['x', 'y']]
        assert_array_equal(coords_actual, np.array(coords[0:2], dtype=float))
        self.assertEqual(new_id, 8)

    def test_add_element(self):
        mesh = Mesh(2)
        for nodeid, coords in zip(self._nodeids, self._nodes):
            mesh.add_node(coords, nodeid)

        conn_desired = np.array([5, 6, 3], dtype=np.int)
        shape_desired = 'Tri3'
        new_id = mesh.add_element(shape_desired, conn_desired)
        shape_actual = mesh.get_ele_shapes_by_elementids([new_id])[0]
        conn_actual = mesh.get_connectivity_by_elementids([new_id])[0]
        self.assertEqual(shape_actual, shape_desired)
        assert_array_equal(conn_actual, conn_desired)

        conn_desired = np.array([4, 1], dtype=np.int)
        shape_desired = 'straight_line'
        new_id = mesh.add_element(shape_desired, conn_desired)
        shape_actual = mesh.get_ele_shapes_by_elementids([new_id])[0]
        conn_actual = mesh.get_connectivity_by_elementids([new_id])[0]
        self.assertEqual(shape_actual, shape_desired)
        assert_array_equal(conn_actual, conn_desired)

        conn_desired = np.array([3, 2, 5], dtype=np.int)
        shape_desired = 'Tri3'
        new_id = mesh.add_element(shape_desired,
                                  np.array([3, 2, 5], dtype=np.int), 5)
        shape_actual = mesh.get_ele_shapes_by_elementids([new_id])[0]
        conn_actual = mesh.get_connectivity_by_elementids([new_id])[0]
        self.assertEqual(shape_actual, shape_desired)
        assert_array_equal(conn_actual, conn_desired)
        self.assertEqual(new_id, 5)

        with self.assertRaises(ValueError):
            mesh.add_element('Quad4', np.array([1, 2, 3, 4], dtype=np.int), 5)

        conn_desired = np.array([1, 2, 3, 4], dtype=np.int)
        shape_desired = 'Quad4'
        new_id = mesh.add_element('Quad4',
                                  np.array([1, 2, 3, 4], dtype=np.int),
                                  5,
                                  overwrite=True)
        shape_actual = mesh.get_ele_shapes_by_elementids([new_id])[0]
        conn_actual = mesh.get_connectivity_by_elementids([new_id])[0]
        self.assertEqual(shape_actual, shape_desired)
        assert_array_equal(conn_actual, conn_desired)
        self.assertEqual(new_id, 5)

        # Test wrong dtype
        new_id = mesh.add_element('Quad4',
                                  np.array([1, 2, 3, 4], dtype=np.float), 6)
        shape_actual = mesh.get_ele_shapes_by_elementids([new_id])[0]
        conn_actual = mesh.get_connectivity_by_elementids([new_id])[0]
        self.assertEqual(shape_actual, shape_desired)
        assert_array_equal(conn_actual, conn_desired)
        self.assertEqual(new_id, 6)

        # Test with tuple instead of array
        new_id = mesh.add_element('Quad4', (1, 2, 3, 4), 7)
        shape_actual = mesh.get_ele_shapes_by_elementids([new_id])[0]
        conn_actual = mesh.get_connectivity_by_elementids([new_id])[0]
        self.assertEqual(shape_actual, shape_desired)
        assert_array_equal(conn_actual, conn_desired)
        self.assertEqual(new_id, 7)

        # Test wrong shape
        with self.assertRaises(ValueError):
            mesh.add_element('wrong_shape', np.array([1, 2, 3, 4],
                                                     dtype=np.int), 8)

    def test_copy_node_by_id(self):
        nodes_df_old = deepcopy(self.testmesh.nodes_df)
        nodes_df_desired = pd.DataFrame(
            {
                'x': [0.0, 1.0, 1.0, 0.0, 2.0, 2.0, 1.0],
                'y': [0.0, 0.0, 1.0, 1.0, 0.0, 1.0, 1.0]
            },
            index=[1, 2, 3, 4, 5, 6, 7])

        self.testmesh.copy_node_by_id(3)

        assert_frame_equal(self.testmesh.nodes_df, nodes_df_desired)

    def test_iconnectivity(self):
        actual = self.testmesh.iconnectivity
        desired = [
            np.array([4, 5, 2], dtype=np.int),
            np.array([2, 1, 4], dtype=np.int),
            np.array([0, 1, 2, 3], dtype=np.int),
            # boundary elements
            np.array([3, 0], dtype=np.int),
            np.array([4, 5], dtype=np.int)
        ]
        for actual_arr, desired_arr in zip(actual, desired):
            assert_array_equal(desired_arr, actual_arr)

    def test_str(self):
        print(self.testmesh)
class RectangleMesh2D:
    def __init__(self, l, h, n_ele_l, n_ele_h, x_start=0.0, y_start=0.0):
        self.l = l
        self.h = h
        self.n_ele_l = n_ele_l
        self.n_ele_h = n_ele_h
        self.delta_h_x = self.l / self.n_ele_l
        self.delta_h_y = self.h / self.n_ele_h
        self.x_start = x_start
        self.y_start = y_start

        self._mesh = Mesh(2)

    @property
    def mesh(self):
        return self._mesh

    def generate_mesh(self):
        self._create_nodes()
        self._create_elements()

    def _create_nodes(self):
        for i_node_y in np.arange(self.n_ele_h+1):
            for i_node_x in np.arange(self.n_ele_l+1):
                self._mesh.add_node([self.x_start + i_node_x * self.delta_h_x, self.y_start + i_node_y * self.delta_h_y])

    def _create_elements(self):
        for i_ele_y in np.arange(self.n_ele_h):
            for i_ele_x in np.arange(self.n_ele_l):
                node1 = self._mesh.get_nodeid_by_coordinates(self.x_start + i_ele_x * self.delta_h_x,
                                                             self.y_start + i_ele_y * self.delta_h_y)
                node2 = self._mesh.get_nodeid_by_coordinates(self.x_start + (i_ele_x + 1) * self.delta_h_x,
                                                             self.y_start + i_ele_y * self.delta_h_y)
                node3 = self._mesh.get_nodeid_by_coordinates(self.x_start + (i_ele_x + 1) * self.delta_h_x,
                                                             self.y_start + (i_ele_y + 1) * self.delta_h_y)
                node4 = self._mesh.get_nodeid_by_coordinates(self.x_start + i_ele_x * self.delta_h_x,
                                                             self.y_start + (i_ele_y + 1) * self.delta_h_y)
                connectivity = np.array([node1, node2, node3, node4])
                self._mesh.add_element('Quad4', connectivity)

    def add_boundary(self, edge, group_name=None):
        if edge is 'left':
            nodes = self._mesh.get_nodeids_by_coordinate_axis(self.x_start, 'x', 1e-6)
        elif edge is 'right':
            nodes = self._mesh.get_nodeids_by_coordinate_axis(self.x_start+self.l, 'x', 1e-6)
        elif edge is 'bottom':
            nodes = self._mesh.get_nodeids_by_coordinate_axis(self.y_start, 'y', 1e-6)
        elif edge is 'top':
            nodes = self._mesh.get_nodeids_by_coordinate_axis(self.y_start + self.h, 'y', 1e-6)
        else:
            raise ValueError('Unknown edge-type')
        for idx in range(nodes.size-1):
            eleid = self._mesh.add_element('straight_line', np.array([nodes[idx], nodes[idx+1]]))
            if group_name is not None and len(self._mesh.get_groups_by_elementids([eleid])) == 0:
                if group_name in self._mesh.groups:
                    self._mesh.add_element_to_groups(eleid, [group_name])
                else:
                    self._mesh.create_group(group_name, (), [eleid])

    def set_checkerboard_groups(self, segment_length, segment_height, segment_groups):
        n_seg_x = int(round(self.l/segment_length))
        n_seg_y = int(round(self.h/segment_height))
        segments = dict()
        seg = 0
        for seg_y in range(n_seg_y):
            for seg_x in range(n_seg_x):
                if seg_y % 2 == 0:
                    group_name = segment_groups[seg_x % len(segment_groups)]
                else:
                    group_name = segment_groups[(seg_x+1) % len(segment_groups)]
                segments[seg] = {'nodes': {'lowerleft': np.array([seg_x * segment_length, seg_y * segment_height]),
                                           'lowerright': np.array([(seg_x + 1) * segment_length, seg_y * segment_height]),
                                           'upperleft': np.array([seg_x * segment_length, (seg_y + 1) * segment_height]),
                                           'upperright': np.array([(seg_x + 1) * segment_length, (seg_y + 1) * segment_height])},
                                 'group': group_name
                                 }
                seg += 1

        def check_node_in_segment(P1, P2, P3, P4, node):
            edge_x = P2 - P1
            edge_y = P4 - P1
            constraint_x = (np.dot(edge_x, P1) <= np.dot(edge_x, node) <= np.dot(edge_x, P2))
            constraint_y = (np.dot(edge_y, P1) <= np.dot(edge_y, node) <= np.dot(edge_y, P4))
            return constraint_x and constraint_y

        eleids = self._mesh.get_elementids_by_tags(['shape'], ['Quad4'])
        for eleid in eleids:
            nodes = self._mesh.get_nodeids_by_elementids([eleid])
            for idx, seg in segments.items():
                seg_nodes = seg['nodes']
                ele_in_segment = True
                for node in nodes:
                    node_pos = np.array([self._mesh.nodes_df.at[node,'x'], self._mesh.nodes_df.at[node,'y']])
                    if not check_node_in_segment(seg_nodes['lowerleft'], seg_nodes['lowerright'],
                                                 seg_nodes['upperright'], seg_nodes['upperleft'], node_pos):
                        ele_in_segment = False
                        break
                if ele_in_segment:
                    if seg['group'] in self._mesh.groups:
                        self._mesh.add_element_to_groups(eleid, [seg['group']])
                    else:
                        self._mesh.create_group(seg['group'], (), [eleid])
                    break

    def set_homogeneous_group(self, groupname):
        self._mesh.create_group(groupname, (), self._mesh.get_elementids_by_tags(['shape'], ['Quad4']))