Source code for ufl.coefficient

# -*- coding: utf-8 -*-
"""This module defines the Coefficient class and a number
of related classes, including Constant."""

# Copyright (C) 2008-2016 Martin Sandve Aln├Žs
# This file is part of UFL (
# SPDX-License-Identifier:    LGPL-3.0-or-later
# Modified by Anders Logg, 2008-2009.
# Modified by Massimiliano Leoni, 2016.
# Modified by Cecile Daversin-Catty, 2018.

from ufl.log import error
from ufl.core.ufl_type import ufl_type
from ufl.core.terminal import FormArgument
from ufl.finiteelement import FiniteElementBase
from ufl.domain import default_domain
from ufl.functionspace import AbstractFunctionSpace, FunctionSpace, MixedFunctionSpace
from ufl.split_functions import split
from ufl.utils.counted import counted_init

# --- The Coefficient class represents a coefficient in a form ---

[docs]@ufl_type() class Coefficient(FormArgument): """UFL form argument type: Representation of a form coefficient.""" # Slots are disabled here because they cause trouble in PyDOLFIN # multiple inheritance pattern: # __slots__ = ("_count", "_ufl_function_space", "_repr", "_ufl_shape") _ufl_noslots_ = True _globalcount = 0 def __init__(self, function_space, count=None): FormArgument.__init__(self) counted_init(self, count, Coefficient) if isinstance(function_space, FiniteElementBase): # For legacy support for .ufl files using cells, we map # the cell to The Default Mesh element = function_space domain = default_domain(element.cell()) function_space = FunctionSpace(domain, element) elif not isinstance(function_space, AbstractFunctionSpace): error("Expecting a FunctionSpace or FiniteElement.") self._ufl_function_space = function_space self._ufl_shape = function_space.ufl_element().value_shape() self._repr = "Coefficient(%s, %s)" % ( repr(self._ufl_function_space), repr(self._count))
[docs] def count(self): return self._count
@property def ufl_shape(self): "Return the associated UFL shape." return self._ufl_shape
[docs] def ufl_function_space(self): "Get the function space of this coefficient." return self._ufl_function_space
[docs] def ufl_domain(self): "Shortcut to get the domain of the function space of this coefficient." return self._ufl_function_space.ufl_domain()
[docs] def ufl_element(self): "Shortcut to get the finite element of the function space of this coefficient." return self._ufl_function_space.ufl_element()
[docs] def is_cellwise_constant(self): "Return whether this expression is spatially constant over each cell." return self.ufl_element().is_cellwise_constant()
[docs] def ufl_domains(self): "Return tuple of domains related to this terminal object." return self._ufl_function_space.ufl_domains()
def _ufl_signature_data_(self, renumbering): "Signature data for form arguments depend on the global numbering of the form arguments and domains." count = renumbering[self] fsdata = self._ufl_function_space._ufl_signature_data_(renumbering) return ("Coefficient", count, fsdata) def __str__(self): count = str(self._count) if len(count) == 1: return "w_%s" % count else: return "w_{%s}" % count def __repr__(self): return self._repr def __eq__(self, other): if not isinstance(other, Coefficient): return False if self is other: return True return (self._count == other._count and self._ufl_function_space == other._ufl_function_space)
# --- Helper functions for subfunctions on mixed elements ---
[docs]def Coefficients(function_space): """UFL value: Create a Coefficient in a mixed space, and return a tuple with the function components corresponding to the subelements.""" if isinstance(function_space, MixedFunctionSpace): return [Coefficient(function_space.ufl_sub_space(i)) for i in range(function_space.num_sub_spaces())] else: return split(Coefficient(function_space))