symfem.elements.bddf

Brezzi-Douglas-Duran-Fortin elements.

This element’s definition appears in https://doi.org/10.1007/BF01396752 (Brezzi, Douglas, Duran, Fortin, 1987)

Classes

BDDF

Brezzi-Douglas-Duran-Fortin Hdiv finite element.

Functions

bddf_polyset(→ list[symfem.functions.FunctionInput])

Create the polynomial basis for a BDDF element.

Module Contents

symfem.elements.bddf.bddf_polyset(reference: symfem.references.Reference, order: int) → list[symfem.functions.FunctionInput]

Create the polynomial basis for a BDDF element.

Parameters:

  • reference – The reference cell

  • order – The polynomial order

Returns:

The polynomial basis

class symfem.elements.bddf.BDDF(reference: symfem.references.Reference, order: int, variant: str = 'equispaced')

Bases: symfem.finite_element.CiarletElement

Brezzi-Douglas-Duran-Fortin Hdiv finite element.

variant = 'equispaced'
init_kwargs() → dict[str, Any]

Return the kwargs used to create this element.

Returns:

Keyword argument dictionary

property lagrange_subdegree: int

Get the Lagrange subdegree of the element.

This is the degree of the highest degree Lagrange space whose polynomial space is a subspace of this element’s polynomial space.

property lagrange_superdegree: int | None

Get the Lagrange superdegree of the element.

This is the degree of the highest degree Lagrange space whose polynomial space is a superspace of this element’s polynomial space.

property polynomial_subdegree: int

Get the polynomial subdegree of the element.

This is the degree of the highest degree complete polynomial space that is a subspace of this element’s polynomial space.

property polynomial_superdegree: int | None

Get the polynomial superdegree of the element.

This is the degree of the highest degree complete polynomial space that is a superspace of this element’s polynomial space.

names = ['Brezzi-Douglas-Duran-Fortin', 'BDDF']
references = ['hexahedron']
min_order = 1
continuity = 'H(div)'
value_type = 'vector'
last_updated = '2023.06'