/usr/lib/python2.7/dist-packages/ufl/variable.py is in python-ufl 2016.2.0-2.
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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 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 | # -*- coding: utf-8 -*-
"""Defines the Variable and Label classes, used to label
expressions as variables for differentiation."""
# Copyright (C) 2008-2016 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/>.
from ufl.utils.counted import counted_init
from ufl.utils.py23 import as_native_str
from ufl.utils.py23 import as_native_strings
from ufl.log import error
from ufl.core.expr import Expr
from ufl.core.ufl_type import ufl_type
from ufl.core.terminal import Terminal
from ufl.core.operator import Operator
from ufl.constantvalue import as_ufl
@ufl_type()
class Label(Terminal):
__slots__ = as_native_strings(("_count",))
_globalcount = 0
def __init__(self, count=None):
Terminal.__init__(self)
counted_init(self, count, Label)
def count(self):
return self._count
def __str__(self):
return "Label(%d)" % self._count
def __repr__(self):
r = "Label(%d)" % self._count
return as_native_str(r)
@property
def ufl_shape(self):
error("Label has no shape (it is not a tensor expression).")
@property
def ufl_free_indices(self):
error("Label has no free indices (it is not a tensor expression).")
@property
def ufl_index_dimensions(self):
error("Label has no free indices (it is not a tensor expression).")
def is_cellwise_constant(self):
return True
def ufl_domains(self):
"Return tuple of domains related to this terminal object."
return ()
@ufl_type(is_shaping=True, is_index_free=True, num_ops=1, inherit_shape_from_operand=0)
class Variable(Operator):
"""A Variable is a representative for another expression.
It will be used by the end-user mainly for defining
a quantity to differentiate w.r.t. using diff.
Example::
e = <...>
e = variable(e)
f = exp(e**2)
df = diff(f, e)
"""
__slots__ = ()
def __init__(self, expression, label=None):
# Conversion
expression = as_ufl(expression)
if label is None:
label = Label()
# Checks
if not isinstance(expression, Expr):
error("Expecting Expr.")
if not isinstance(label, Label):
error("Expecting a Label.")
if expression.ufl_free_indices:
error("Variable cannot wrap an expression with free indices.")
Operator.__init__(self, (expression, label))
def ufl_domains(self):
return self.ufl_operands[0].ufl_domains()
def evaluate(self, x, mapping, component, index_values):
a = self.ufl_operands[0].evaluate(x, mapping, component, index_values)
return a
def expression(self):
return self.ufl_operands[0]
def label(self):
return self.ufl_operands[1]
def __eq__(self, other):
return (isinstance(other, Variable) and
self.ufl_operands[1] == other.ufl_operands[1] and
self.ufl_operands[0] == other.ufl_operands[0])
def __str__(self):
return "var%d(%s)" % (self.ufl_operands[1].count(),
self.ufl_operands[0])
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