/usr/lib/python3/dist-packages/ufl/checks.py is in python3-ufl 2017.2.0.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 | # -*- coding: utf-8 -*-
"""Utility functions for checking properties of expressions."""
# Copyright (C) 2013-2016 Martin Sandve Alnæs
#
# This file is part of UFL.
#
# UFL is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# UFL is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with UFL. If not, see <http://www.gnu.org/licenses/>.
#
# Modified by Anders Logg, 2008-2009
from ufl.core.expr import Expr
from ufl.corealg.traversal import traverse_unique_terminals
def is_python_scalar(expression):
"Return True iff expression is of a Python scalar type."
return isinstance(expression, (int, float))
def is_ufl_scalar(expression):
"""Return True iff expression is scalar-valued,
but possibly containing free indices."""
return isinstance(expression, Expr) and not expression.ufl_shape
def is_true_ufl_scalar(expression):
"""Return True iff expression is scalar-valued,
with no free indices."""
return isinstance(expression, Expr) and \
not (expression.ufl_shape or expression.ufl_free_indices)
def is_cellwise_constant(expr):
"Return whether expression is constant over a single cell."
# TODO: Implement more accurately considering e.g. derivatives?
return all(t.is_cellwise_constant() for t in traverse_unique_terminals(expr))
def is_globally_constant(expr):
"""Check if an expression is globally constant, which
includes spatially independent constant coefficients that
are not known before assembly time."""
# TODO: This does not consider gradients of coefficients, so false
# negatives are possible.
# from ufl.argument import Argument
# from ufl.coefficient import Coefficient
from ufl.geometry import GeometricQuantity
from ufl.core.terminal import FormArgument
for e in traverse_unique_terminals(expr):
# Return False if any single terminal is not constant
if e._ufl_is_literal_:
# Accept literals first, they are the most common
# terminals
continue
elif isinstance(e, FormArgument):
# Accept only Real valued Arguments and Coefficients
if e.ufl_element().family() == "Real":
continue
else:
return False
elif isinstance(e, GeometricQuantity):
# Reject all geometric quantities, they all vary over
# cells
return False
# All terminals passed constant check
return True
def is_scalar_constant_expression(expr):
"""Check if an expression is a globally constant scalar expression."""
if is_python_scalar(expr):
return True
if expr.ufl_shape:
return False
return is_globally_constant(expr)
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