sktopt.mesh.task

class sktopt.mesh.task.TaskConfig(E: float, nu: float, basis: CellBasis, dirichlet_nodes: ndarray, dirichlet_dofs: ndarray, dirichlet_elements: ndarray, force_nodes: ndarray | list[ndarray], force_elements: ndarray, force: ndarray | list[ndarray], design_elements: ndarray, free_dofs: ndarray, free_elements: ndarray, all_elements: ndarray, fixed_elements: ndarray, dirichlet_force_elements: ndarray, elements_volume: ndarray)

Bases: object

Container for storing finite element and optimization-related data used in topology optimization tasks.

This class holds material properties, boundary condition information, designable and non-designable element indices, as well as force vectors and volume data for each element. It is typically constructed using TaskConfig.from_defaults.

E

Young’s modulus of the base material.

Type:

float

nu

Poisson’s ratio of the base material.

Type:

float

basis

Finite element basis object associated with the mesh and function space.

Type:

skfem.Basis

dirichlet_dofs

Degrees of freedom constrained by Dirichlet (displacement) boundary conditions.

Type:

np.ndarray

dirichlet_elements

Elements that contain Dirichlet boundary points.

Type:

np.ndarray

force_elements

Elements that contain the force application points.

Type:

np.ndarray

force

External force vector(s) applied to the system. A list is used when multiple load cases are present.

Type:

np.ndarray or list of np.ndarray

design_elements

Indices of elements that are considered designable in the optimization.

Type:

np.ndarray

free_dofs

Degrees of freedom that are not fixed by boundary conditions.

Type:

np.ndarray

free_elements

Elements associated with the free degrees of freedom.

Type:

np.ndarray

all_elements

Array of all element indices in the mesh.

Type:

np.ndarray

fixed_elements

Elements excluded from the design domain.

Type:

np.ndarray

dirichlet_force_elements

Union of Dirichlet and force elements. Useful for identifying constrained and loaded regions.

Type:

np.ndarray

elements_volume

Volume of each finite element, used in volume constraints and integration.

Type:

np.ndarray

E: float
all_elements: ndarray
basis: CellBasis
design_elements: ndarray
property design_mask
dirichlet_dofs: ndarray
dirichlet_elements: ndarray
dirichlet_force_elements: ndarray
dirichlet_nodes: ndarray
elements_volume: ndarray
exlude_dirichlet_from_design()
export_analysis_condition_on_mesh(dst_path: str)
fixed_elements: ndarray
force: ndarray | list[ndarray]
force_elements: ndarray
force_nodes: ndarray | list[ndarray]
property force_nodes_all: ndarray
free_dofs: ndarray
free_elements: ndarray
classmethod from_facets(E: float, nu: float, basis: CellBasis, dirichlet_facets_ids: ndarray | list[ndarray], dirichlet_dir: Literal['u^1', 'u^2', 'u^3', 'all'] | list[Literal['u^1', 'u^2', 'u^3', 'all']], force_facets_ids: ndarray | list[ndarray], force_dir_type: str | list[str], force_value: float | list[float], design_elements: ndarray) → TaskConfig

Create a TaskConfig from facet-based boundary-condition specifications.

This constructor allows you to specify Dirichlet and Neumann boundaries directly via facet indices (rather than node indices). It will internally:

  • Convert dirichlet_facets_ids into the corresponding Dirichlet node set.

  • Resolve Dirichlet DOFs from those nodes and dirichlet_dir.

  • Convert force_facets_ids into the corresponding force node set.

  • Assemble the Neumann (surface) load vector(s) using

    assemble_surface_forces.

  • Forward all data to TaskConfig.from_nodes to build the final config.

Parameters:

  • E (float) – Young’s modulus.

  • nu (float) – Poisson’s ratio.

  • basis (skfem.Basis) – Finite-element space providing mesh and DOFs.

  • dirichlet_facets_ids (np.ndarray or list[np.ndarray]) – Indices of facets subject to Dirichlet boundary conditions. If a list is given, each entry corresponds to a boundary region.

  • dirichlet_dir (_lit_bc or list[_lit_bc]) – Direction specifier(s) for Dirichlet constraints. _lit_bc = Literal[‘u^1’, ‘u^2’, ‘u^3’, ‘all’] - ‘all’ fixes all displacement components. - ‘u^1’, ‘u^2’, ‘u^3’ fix the respective component only.

  • force_facets_ids (np.ndarray or list[np.ndarray]) – Indices of facets subject to Neumann (surface) forces. A list denotes multiple load regions.

  • force_dir_type (str or list[str]) – Direction specifier(s) for each force region. _lit_force = Literal[‘u^1’, ‘u^2’, ‘u^3’] Indicates along which component the surface load is applied.

  • force_value (float or list[float]) – Magnitude(s) of the surface forces, one per region if multiple.

  • design_elements (np.ndarray) – Element indices initially considered designable. Force-touching elements will be excluded downstream.

Returns:

A fully initialized TaskConfig, equivalent to what TaskConfig.from_nodes produces but constructed from facet-based specifications.

Return type:

TaskConfig

classmethod from_json(path: str)
classmethod from_mesh_tags(E: float, nu: float, basis: CellBasis, dirichlet_dir: Literal['u^1', 'u^2', 'u^3', 'all'] | list[Literal['u^1', 'u^2', 'u^3', 'all']], force_dir_type: str | list[str], force_value: float | list[float]) → TaskConfig
classmethod from_nodes(E: float, nu: float, basis: CellBasis, dirichlet_nodes: ndarray | list[ndarray], dirichlet_dir: Literal['u^1', 'u^2', 'u^3', 'all'] | list[Literal['u^1', 'u^2', 'u^3', 'all']], force_nodes: ndarray | list[ndarray], force: ndarray | list[ndarray], design_elements: ndarray) → TaskConfig

Create a TaskConfig from material parameters and boundary-condition specifications expressed by node-index sets.

This constructor:

  • Resolves Dirichlet DOFs from dirichlet_nodes and dirichlet_dir.

  • Identifies Dirichlet/Neumann (force) elements that touch those nodes.

  • Builds load vector(s) from force and filters out non-designable elements.

  • Derives sets such as free DOFs/elements and fixed/design elements.

  • Precomputes per-element volumes.

Parameters:

  • E (float) – Young’s modulus.

  • nu (float) – Poisson’s ratio.

  • basis (skfem.Basis) – Finite-element space (provides mesh, DOFs, etc.).

  • dirichlet_nodes (np.ndarray or list[np.ndarray]) – Global node indices that define Dirichlet boundaries. If a list is provided, it must align one-to-one with dirichlet_dir.

  • dirichlet_dir (_lit_bc or list[_lit_bc]) – Direction specifier(s) for Dirichlet constraints. _lit_bc = Literal[‘u^1’, ‘u^2’, ‘u^3’, ‘all’] Use ‘all’ to fix all components, or ‘u^1’|’u^2’|’u^3’ to fix a single component (compatible with basis.get_dofs(…).nodal[…]). When dirichlet_nodes is a list, this must be a list of equal length.

  • force_nodes (np.ndarray or list[np.ndarray]) – Global node indices where Neumann (external) loads are applied. A list denotes multiple load regions (load cases).

  • force (np.ndarray or list[np.ndarray]) – Load vector(s) associated with force_nodes. Provide a list to match multiple regions/cases. Each vector should already be assembled in the global DOF ordering expected by the solver.

  • design_elements (np.ndarray) – Element indices initially considered designable. Elements touching force_nodes are removed from this set.

Returns:

A fully initialized configuration containing:

  • material parameters (E, nu)

  • mesh/basis

  • dirichlet_nodes, dirichlet_dofs, dirichlet_elements

  • force_nodes, force_elements, force

  • filtered design_elements

  • free_dofs, free_elements

  • all_elements, fixed_elements, dirichlet_force_elements

  • elements_volume

Return type:

TaskConfig

Notes

  • Element sets are computed via utils.get_elements_by_nodes(…), i.e., elements touching the provided node sets.

  • free_dofs = all DOFs dirichlet_dofs; free_elements are elements touching free_dofs (convenience for downstream assembly/solves).

  • If you prefer facet-based specification (with direction literals for surface forces, e.g., _lit_force = Literal[‘u^1’,’u^2’,’u^3’]), consider using TaskConfig.from_facets(…) which will assemble surface loads internally.

property mesh
nodes_and_elements_stats(dst_path: str)
nu: float
scale(L_scale: float, F_scale: float)
sktopt.mesh.task.assemble_surface_forces(basis, force_facets_ids: ndarray | List[ndarray], force_dir_type: str | List[str], force_value: float | List[float], *, treat_value_as_total_force: bool = True)
sktopt.mesh.task.setdiff1d(a, b)