84 lines
2.7 KiB
Python
84 lines
2.7 KiB
Python
![]() |
# Copyright 2016 The TensorFlow Authors. All Rights Reserved.
|
||
|
#
|
||
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
# you may not use this file except in compliance with the License.
|
||
|
# You may obtain a copy of the License at
|
||
|
#
|
||
|
# http://www.apache.org/licenses/LICENSE-2.0
|
||
|
#
|
||
|
# Unless required by applicable law or agreed to in writing, software
|
||
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
# See the License for the specific language governing permissions and
|
||
|
# limitations under the License.
|
||
|
# ==============================================================================
|
||
|
"""Converter for slice operations."""
|
||
|
|
||
|
import gast
|
||
|
|
||
|
from tensorflow.python.autograph.core import converter
|
||
|
from tensorflow.python.autograph.lang import directives
|
||
|
from tensorflow.python.autograph.pyct import templates
|
||
|
|
||
|
|
||
|
class SliceTransformer(converter.Base):
|
||
|
"""Converts slicing operations to their TF counterpart.
|
||
|
|
||
|
Currently, relying on the default slice operator that Tensor uses is
|
||
|
insufficient, because TensorArray and tensor lists use dedicated index read
|
||
|
and write functions.
|
||
|
"""
|
||
|
|
||
|
def _process_single_assignment(self, target, value):
|
||
|
if not isinstance(target, gast.Subscript):
|
||
|
return None
|
||
|
s = target.slice
|
||
|
if isinstance(s, (gast.Tuple, gast.Slice)):
|
||
|
return None
|
||
|
|
||
|
template = """
|
||
|
target = ag__.set_item(target, key, item)
|
||
|
"""
|
||
|
return templates.replace(
|
||
|
template, target=target.value, key=target.slice, item=value)
|
||
|
|
||
|
def visit_Assign(self, node):
|
||
|
node = self.generic_visit(node)
|
||
|
# TODO(mdan): Support unpackings and multiple assignments.
|
||
|
if len(node.targets) != 1:
|
||
|
raise NotImplementedError('multiple assignment')
|
||
|
replacement = self._process_single_assignment(node.targets[0], node.value)
|
||
|
if replacement is not None:
|
||
|
return replacement
|
||
|
return node
|
||
|
|
||
|
def visit_Subscript(self, node):
|
||
|
node = self.generic_visit(node)
|
||
|
s = node.slice
|
||
|
if isinstance(s, (gast.Tuple, gast.Slice)):
|
||
|
return node
|
||
|
|
||
|
if not isinstance(node.ctx, gast.Load):
|
||
|
# Index writes are handled at a higher level, one at which the rvalue is
|
||
|
# also available.
|
||
|
return node
|
||
|
|
||
|
dtype = self.get_definition_directive(
|
||
|
node.value,
|
||
|
directives.set_element_type,
|
||
|
'dtype',
|
||
|
default=templates.replace_as_expression('None'))
|
||
|
|
||
|
template = """
|
||
|
ag__.get_item(
|
||
|
target,
|
||
|
key,
|
||
|
opts=ag__.GetItemOpts(element_dtype=dtype))
|
||
|
"""
|
||
|
return templates.replace_as_expression(
|
||
|
template, target=node.value, key=s, dtype=dtype)
|
||
|
|
||
|
|
||
|
def transform(node, ctx):
|
||
|
return SliceTransformer(ctx).visit(node)
|