qtcad.device.mesh2d module

2d Mesh and SubMesh classes.

class qtcad.device.mesh2d.Mesh(scaling_factor, filename, verbose=True)

Bases: poissonfem.fem2d.mesh.Mesh

Class to store and process mesh properties such as node coordinates and elements.

Attributes

  • dim (int) – Dimension of the mesh

  • tri_number (int) – Number of triangular elements in the mesh.

  • line_number (int) – Number of line elements in the mesh.

  • node_number (int) – Number of global nodes.

  • glob_nodes (2D array) – Coordinates of the global nodes. First array index: global node index. Second array index: Cartesian direction (x or y).

  • elem_number (int) – Number of elements in the mesh including boundary elements.

  • all_connectivity (list) – Global nodes contained by all elements, including boundary elements.

  • connectivity (2D array) – Global nodes contained by each line element. The row index labels distinct elements, while the column index labels local nodes for each element, so the array shape is Ntriang x 3, where Ntriang is the number of triangular elements. Values stored in the array are global node indices, starting from 0.

__init__(scaling_factor, filename, verbose=True)

Constructor for the mesh class.

Parameters

  • scaling_factor (float) – Factor by which node coordinates are multiplied to correspond to SI units.

  • filename (str) – Path to the mesh file to use to build the mesh.

  • verbose (bool, optional) – If True, print mesh statistics. Default: True.

centroids()

Calculate the centroid of each triangular element.

Returns

2D array – Centroid of each element.

Note

The output is a 2D array corresponding to a column vector to comply with the indexing convention used for higher dimensinal meshes

loc_node_coords()

Get arrays containing the local-node coordinates for each element.

Returns

tuple – a tuple (x_loc_nodes, y_loc_nodes) where x_loc_nodes (y_loc_nodes) is a 2D array containing the x (y) coordinate at each local node (column idx) and element (row idx)

nodes_in_box(coords_min, coords_max)

Gets indices of global nodes within a box.

Parameters

  • coords_min (tuple) – Minimum xy coordinate values.

  • coords_max (tuple) – Maximum xy coordinate values.

Returns

1d array of int – The indices of the global nodes within the box.

show(length_unit='nm')

Display the mesh using pyplot.

Parameters

length_unit (str, optional) – Units of length to use when plotting. Default: “nm”. Other choices are: “um”, “mm”, and “m”.

tri_areas()

Calculate the area of each triangular element.

Returns

1D array – The area of each element.

class qtcad.device.mesh2d.SubMesh(parent, nodes, verbose=True)

Bases: poissonfem.fem2d.mesh.SubMesh

A submesh is a subset of a parent mesh.

Attributes

nodes_in_parent (1d array) – Number of each node belonging to the submesh in the parent mesh.

Note

All other attributes are inherited from the parent mesh.

__init__(parent, nodes, verbose=True)

Constructor of the submesh class.

Parameters

  • parent (mesh object) – The parent mesh.

  • nodes (1d array, string, or list of strings) – The nodes defining the subset of the parent mesh, or region label, or list of region labels.

  • verbose (bool, optional) – If True, print mesh statistics. Default: True.