grains.med.get_elements

grains.med.get_elements(mesh, numbering='global')[source]

Obtains the elements for each group of a mesh.

Elements of the same dimension as the mesh are collected (e.g. faces for a 2D mesh).

Todo

put those elements that do not belong to any group into an automatically created group

Todo

support ordering elements in alphabetical order

Todo

implement the ‘global’ strategy

Parameters

  • mesh (MEDFileUMesh) – Unstructured mesh.

  • numbering ({‘global’}, optional) –

    Determines how to allocate element numbers in the mesh.

    ‘global’: numbers the elements without taking into account which group they belong to. Use this strategy if you are not sure whether an element belongs to more than one group. ‘group’: numbers the elements group-wise. This is much faster than the ‘global’ strategy, but use this option if you are sure that the groups of the mesh do not contain common elements.

    The default is ‘global’.

Returns

  • elements (ndarray) – Element-node connectivities in a 2D numpy array, in which each row corresponds to an element and the columns are the nodes of the elements. It is assumed that all the elements have the same number of nodes.

  • element_groups (dict) – The keys in the dictionary are the element group names, while the values are list of integers, giving the elements that belong to the particular group.

Warning

Currently, elements that do not fit into any groups are discarded.

See also

get_nodes(), change_node_numbering()

Notes

The element-node connectivities are read from the mesh. If you want to change the ordering of the nodes, use the change_node_numbering() function.

Both this and the get_nodes() function relies on getGroupsOnSpecifiedLev to obtain the groups based on a parameter, called meshDimRelToMaxExt. This parameter designates the relative dimension of the mesh entities whose IDs are required. If it is 1, it denotes the nodes. If 0, entities of the same dimension as the mesh are meant (e.g. group of volumes for a 3D mesh, or group of faces for a 2D mesh). When -1, entities of spatial dimension immediately below that of the mesh are collected (e.g. group of faces for a 3D mesh, or group of edges for a 2D mesh). For -2, entities of two dimensions below that of the mesh are fetched (e.g. group of edges for a 3D mesh).