Source code for ffcx.element_interface

# Copyright (C) 2021 Matthew W. Scroggs and Chris Richardson
# This file is part of FFCx.(
# SPDX-License-Identifier:    LGPL-3.0-or-later
"""Finite element interface."""

import typing
import warnings

import basix
import basix.ufl
import ufl
import numpy as np
import numpy.typing as npt

[docs]def convert_element(element: ufl.finiteelement.FiniteElementBase) -> basix.ufl._ElementBase: """Convert and element to a FFCx element.""" if isinstance(element, basix.ufl._ElementBase): return element else: warnings.warn( "Use of elements created by UFL is deprecated. You should create elements directly using Basix.", DeprecationWarning) return basix.ufl.convert_ufl_element(element)
[docs]def basix_index(indices: typing.Tuple[int]) -> int: """Get the Basix index of a derivative.""" return basix.index(*indices)
[docs]def create_quadrature( cellname: str, degree: int, rule: str, elements: typing.List[basix.ufl._ElementBase] ) -> typing.Tuple[npt.NDArray[np.float64], npt.NDArray[np.float64]]: """Create a quadrature rule.""" if cellname == "vertex": return (np.ones((1, 0), dtype=np.float64), np.ones(1, dtype=np.float64)) else: celltype = basix.cell.string_to_type(cellname) polyset_type = basix.PolysetType.standard for e in elements: polyset_type = basix.polyset_superset(celltype, polyset_type, e.polyset_type) return basix.make_quadrature( celltype, degree, rule=basix.quadrature.string_to_type(rule), polyset_type=polyset_type)
[docs]def reference_cell_vertices(cellname: str) -> npt.NDArray[np.float64]: """Get the vertices of a reference cell.""" return basix.geometry(basix.cell.string_to_type(cellname))
[docs]def map_facet_points(points: npt.NDArray[np.float64], facet: int, cellname: str) -> npt.NDArray[np.float64]: """Map points from a reference facet to a physical facet.""" geom = basix.geometry(basix.cell.string_to_type(cellname)) facet_vertices = [geom[i] for i in basix.topology(basix.cell.string_to_type(cellname))[-2][facet]] return np.asarray([facet_vertices[0] + sum((i - facet_vertices[0]) * j for i, j in zip(facet_vertices[1:], p)) for p in points], dtype=np.float64)
# TODO: remove this deprecated function
[docs]def QuadratureElement( cellname: str, value_shape: typing.Tuple[int, ...], scheme: typing.Optional[str] = None, degree: typing.Optional[int] = None, points: typing.Optional[npt.NDArray[np.float64]] = None, weights: typing.Optional[npt.NDArray[np.float64]] = None, mapname: str = "identity" ) -> basix.ufl._ElementBase: warnings.warn( "ffcx.element_interface.QuadratureElement is deprecated and will be removed after December 2023. " "Use basix.ufl.quadrature_element instead.", DeprecationWarning) return basix.ufl.quadrature_element( cell=cellname, value_shape=value_shape, scheme=scheme, degree=degree, points=points, weights=weights, mapname=mapname)
# TODO: remove this deprecated function
[docs]def RealElement(element: ufl.finiteelement.FiniteElementBase) -> basix.ufl._ElementBase: warnings.warn( "ffcx.element_interface.RealElement is deprecated and will be removed after December 2023. " "Use basix.ufl.real_element instead.", DeprecationWarning) return basix.ufl.real_element(cell=element.cell().cellname(), value_shape=element.value_shape())