# -*- coding: utf-8 -*-
"""This module defines the Indexed class."""
# Copyright (C) 2008-2016 Martin Sandve Alnæs
#
# This file is part of UFL (https://www.fenicsproject.org)
#
# SPDX-License-Identifier: LGPL-3.0-or-later
from ufl.log import error
from ufl.constantvalue import Zero
from ufl.core.expr import Expr, ufl_err_str
from ufl.core.ufl_type import ufl_type
from ufl.core.operator import Operator
from ufl.core.multiindex import Index, FixedIndex, MultiIndex
from ufl.index_combination_utils import unique_sorted_indices, merge_unique_indices
from ufl.precedence import parstr
# --- Indexed expression ---
[docs]@ufl_type(is_shaping=True, num_ops=2, is_terminal_modifier=True)
class Indexed(Operator):
__slots__ = (
"ufl_free_indices",
"ufl_index_dimensions",
)
def __new__(cls, expression, multiindex):
if isinstance(expression, Zero):
# Zero-simplify indexed Zero objects
shape = expression.ufl_shape
efi = expression.ufl_free_indices
efid = expression.ufl_index_dimensions
fi = list(zip(efi, efid))
for pos, ind in enumerate(multiindex._indices):
if isinstance(ind, Index):
fi.append((ind.count(), shape[pos]))
fi = unique_sorted_indices(sorted(fi))
if fi:
fi, fid = zip(*fi)
else:
fi, fid = (), ()
return Zero(shape=(), free_indices=fi, index_dimensions=fid)
elif expression.ufl_shape == () and multiindex == ():
return expression
else:
return Operator.__new__(cls)
def __init__(self, expression, multiindex):
# Store operands
Operator.__init__(self, (expression, multiindex))
# Error checking
if not isinstance(expression, Expr):
error("Expecting Expr instance, not %s." % ufl_err_str(expression))
if not isinstance(multiindex, MultiIndex):
error("Expecting MultiIndex instance, not %s." % ufl_err_str(multiindex))
shape = expression.ufl_shape
# Error checking
if len(shape) != len(multiindex):
error("Invalid number of indices (%d) for tensor "
"expression of rank %d:\n\t%s\n"
% (len(multiindex), len(expression.ufl_shape), ufl_err_str(expression)))
if any(int(di) >= int(si) or int(di) < 0
for si, di in zip(shape, multiindex)
if isinstance(di, FixedIndex)):
error("Fixed index out of range!")
# Build tuples of free index ids and dimensions
if 1:
efi = expression.ufl_free_indices
efid = expression.ufl_index_dimensions
fi = list(zip(efi, efid))
for pos, ind in enumerate(multiindex._indices):
if isinstance(ind, Index):
fi.append((ind.count(), shape[pos]))
fi = unique_sorted_indices(sorted(fi))
if fi:
fi, fid = zip(*fi)
else:
fi, fid = (), ()
else:
mfiid = [(ind.count(), shape[pos])
for pos, ind in enumerate(multiindex._indices)
if isinstance(ind, Index)]
mfi, mfid = zip(*mfiid) if mfiid else ((), ())
fi, fid = merge_unique_indices(expression.ufl_free_indices,
expression.ufl_index_dimensions,
mfi, mfid)
# Cache free index and dimensions
self.ufl_free_indices = fi
self.ufl_index_dimensions = fid
ufl_shape = ()
[docs] def evaluate(self, x, mapping, component, index_values, derivatives=()):
A, ii = self.ufl_operands
component = ii.evaluate(x, mapping, None, index_values)
if derivatives:
return A.evaluate(x, mapping, component, index_values, derivatives)
else:
return A.evaluate(x, mapping, component, index_values)
def __str__(self):
return "%s[%s]" % (parstr(self.ufl_operands[0], self),
self.ufl_operands[1])
def __getitem__(self, key):
if key == ():
# So that one doesn't have to special case indexing of
# expressions without shape.
return self
error("Attempting to index with %s, but object is already indexed: %s" % (ufl_err_str(key), ufl_err_str(self)))