162 lines
7.1 KiB
Python
162 lines
7.1 KiB
Python
# Copyright 2018 The TensorFlow Authors. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ==============================================================================
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"""Experimental `dataset` API for parsing example."""
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from tensorflow.python.data.ops import dataset_ops
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from tensorflow.python.data.util import structure
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from tensorflow.python.framework import dtypes
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from tensorflow.python.framework import sparse_tensor
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from tensorflow.python.framework import tensor_spec
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from tensorflow.python.ops import gen_experimental_dataset_ops
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from tensorflow.python.ops import parsing_ops
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from tensorflow.python.ops.ragged import ragged_tensor
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from tensorflow.python.util import deprecation
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from tensorflow.python.util.tf_export import tf_export
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class _ParseExampleDataset(dataset_ops.UnaryDataset):
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"""A `Dataset` that parses `example` dataset into a `dict` dataset."""
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def __init__(self, input_dataset, features, num_parallel_calls,
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deterministic):
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self._input_dataset = input_dataset
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if not structure.are_compatible(
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input_dataset.element_spec,
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tensor_spec.TensorSpec([None], dtypes.string)):
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raise TypeError("Input dataset should be a dataset of vectors of "
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f"strings. Instead it is `{input_dataset.element_spec}`.")
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self._num_parallel_calls = num_parallel_calls
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if deterministic is None:
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self._deterministic = "default"
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elif deterministic:
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self._deterministic = "true"
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else:
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self._deterministic = "false"
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# pylint: disable=protected-access
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self._features = parsing_ops._prepend_none_dimension(features)
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params = parsing_ops._ParseOpParams.from_features(self._features, [
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parsing_ops.VarLenFeature, parsing_ops.SparseFeature,
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parsing_ops.FixedLenFeature, parsing_ops.FixedLenSequenceFeature,
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parsing_ops.RaggedFeature
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])
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# pylint: enable=protected-access
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self._sparse_keys = params.sparse_keys
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self._sparse_types = params.sparse_types
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self._ragged_keys = params.ragged_keys
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self._ragged_value_types = params.ragged_value_types
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self._ragged_split_types = params.ragged_split_types
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self._dense_keys = params.dense_keys
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self._dense_defaults = params.dense_defaults_vec
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self._dense_shapes = params.dense_shapes_as_proto
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self._dense_types = params.dense_types
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input_dataset_shape = dataset_ops.get_legacy_output_shapes(
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self._input_dataset)
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self._element_spec = {}
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for (key, value_type) in zip(params.sparse_keys, params.sparse_types):
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self._element_spec[key] = sparse_tensor.SparseTensorSpec(
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input_dataset_shape.concatenate([None]), value_type)
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for (key, value_type, dense_shape) in zip(params.dense_keys,
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params.dense_types,
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params.dense_shapes):
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self._element_spec[key] = tensor_spec.TensorSpec(
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input_dataset_shape.concatenate(dense_shape), value_type)
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for (key, value_type, splits_type) in zip(params.ragged_keys,
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params.ragged_value_types,
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params.ragged_split_types):
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self._element_spec[key] = ragged_tensor.RaggedTensorSpec(
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input_dataset_shape.concatenate([None]), value_type, 1, splits_type)
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variant_tensor = (
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gen_experimental_dataset_ops.parse_example_dataset_v2(
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self._input_dataset._variant_tensor, # pylint: disable=protected-access
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self._num_parallel_calls,
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self._dense_defaults,
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self._sparse_keys,
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self._dense_keys,
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self._sparse_types,
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self._dense_shapes,
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deterministic=self._deterministic,
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ragged_keys=self._ragged_keys,
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ragged_value_types=self._ragged_value_types,
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ragged_split_types=self._ragged_split_types,
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**self._flat_structure))
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super(_ParseExampleDataset, self).__init__(input_dataset, variant_tensor)
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@property
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def element_spec(self):
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return self._element_spec
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@tf_export("data.experimental.parse_example_dataset")
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@deprecation.deprecated(
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None, "Use `tf.data.Dataset.map(tf.io.parse_example(...))` instead.")
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def parse_example_dataset(features, num_parallel_calls=1, deterministic=None):
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"""A transformation that parses `Example` protos into a `dict` of tensors.
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Parses a number of serialized `Example` protos given in `serialized`. We refer
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to `serialized` as a batch with `batch_size` many entries of individual
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`Example` protos.
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This op parses serialized examples into a dictionary mapping keys to `Tensor`,
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`SparseTensor`, and `RaggedTensor` objects. `features` is a dict from keys to
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`VarLenFeature`, `RaggedFeature`, `SparseFeature`, and `FixedLenFeature`
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objects. Each `VarLenFeature` and `SparseFeature` is mapped to a
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`SparseTensor`; each `RaggedFeature` is mapped to a `RaggedTensor`; and each
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`FixedLenFeature` is mapped to a `Tensor`. See `tf.io.parse_example` for more
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details about feature dictionaries.
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Args:
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features: A `dict` mapping feature keys to `FixedLenFeature`,
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`VarLenFeature`, `RaggedFeature`, and `SparseFeature` values.
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num_parallel_calls: (Optional.) A `tf.int32` scalar `tf.Tensor`,
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representing the number of parsing processes to call in parallel.
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deterministic: (Optional.) A boolean controlling whether determinism
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should be traded for performance by allowing elements to be produced out
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of order if some parsing calls complete faster than others. If
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`deterministic` is `None`, the
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`tf.data.Options.deterministic` dataset option (`True` by default) is used
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to decide whether to produce elements deterministically.
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Returns:
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A dataset transformation function, which can be passed to
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`tf.data.Dataset.apply`.
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Raises:
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ValueError: if features argument is None.
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"""
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if features is None:
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raise ValueError("Argument `features` is required, but not specified.")
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def _apply_fn(dataset):
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"""Function from `Dataset` to `Dataset` that applies the transformation."""
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out_dataset = _ParseExampleDataset(dataset, features, num_parallel_calls,
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deterministic)
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if any(
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isinstance(feature, parsing_ops.SparseFeature) or
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isinstance(feature, parsing_ops.RaggedFeature)
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for feature in features.values()):
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# pylint: disable=protected-access
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# pylint: disable=g-long-lambda
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out_dataset = out_dataset.map(
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lambda x: parsing_ops._construct_tensors_for_composite_features(
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features, x),
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num_parallel_calls=num_parallel_calls)
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return out_dataset
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return _apply_fn
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