#
# Copyright (c) 2021, NVIDIA CORPORATION.
#
# 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.
#
from typing import Dict, Optional, Union
import tensorflow as tf
from merlin_standard_lib import Schema, Tag
from merlin_standard_lib.utils.doc_utils import docstring_parameter
from ..block.base import Block, SequentialBlock
from ..block.mlp import MLPBlock
from ..masking import MaskSequence, masking_registry
from ..tabular.base import (
TABULAR_MODULE_PARAMS_DOCSTRING,
AsTabular,
TabularAggregationType,
TabularBlock,
TabularTransformationType,
)
from ..utils import tf_utils
from . import embedding
from .tabular import TABULAR_FEATURES_PARAMS_DOCSTRING, TabularFeatures
[docs]@docstring_parameter(
tabular_module_parameters=TABULAR_MODULE_PARAMS_DOCSTRING,
embedding_features_parameters=embedding.EMBEDDING_FEATURES_PARAMS_DOCSTRING,
)
@tf.keras.utils.register_keras_serializable(package="transformers4rec")
class SequenceEmbeddingFeatures(embedding.EmbeddingFeatures):
"""Input block for embedding-lookups for categorical features. This module produces 3-D tensors,
this is useful for sequential models like transformers.
Parameters
----------
{embedding_features_parameters}
padding_idx: int
The symbol to use for padding.
{tabular_module_parameters}
"""
def __init__(
self,
feature_config: Dict[str, embedding.FeatureConfig],
item_id: Optional[str] = None,
mask_zero: bool = True,
padding_idx: int = 0,
pre: Optional[TabularTransformationType] = None,
post: Optional[TabularTransformationType] = None,
aggregation: Optional[TabularAggregationType] = None,
schema: Optional[Schema] = None,
name: Optional[str] = None,
embedding_tables={},
**kwargs
):
super().__init__(
feature_config,
item_id=item_id,
pre=pre,
post=post,
aggregation=aggregation,
schema=schema,
name=name,
embedding_tables=embedding_tables,
**kwargs,
)
self.padding_idx = padding_idx
self.mask_zero = mask_zero
[docs] def lookup_feature(self, name, val, **kwargs):
return super(SequenceEmbeddingFeatures, self).lookup_feature(
name, val, output_sequence=True
)
[docs] def compute_call_output_shape(self, input_shapes):
batch_size = self.calculate_batch_size_from_input_shapes(input_shapes)
sequence_length = input_shapes[list(self.feature_config.keys())[0]][1]
output_shapes = {}
for name, val in input_shapes.items():
output_shapes[name] = tf.TensorShape(
[batch_size, sequence_length, self.feature_config[name].table.dim]
)
return output_shapes
[docs] def compute_mask(self, inputs, mask=None):
if not self.mask_zero:
return None
outputs = {}
for key, val in inputs.items():
outputs[key] = tf.not_equal(val, self.padding_idx)
return outputs
[docs] def get_config(self):
config = super().get_config()
config["mask_zero"] = self.mask_zero
config["padding_idx"] = self.padding_idx
return config
[docs]@docstring_parameter(
tabular_module_parameters=TABULAR_MODULE_PARAMS_DOCSTRING,
tabular_features_parameters=TABULAR_FEATURES_PARAMS_DOCSTRING,
)
@tf.keras.utils.register_keras_serializable(package="transformers4rec")
class TabularSequenceFeatures(TabularFeatures):
"""Input module that combines different types of features to a sequence: continuous,
categorical & text.
Parameters
----------
{tabular_features_parameters}
projection_module: BlockOrModule, optional
Module that's used to project the output of this module, typically done by an MLPBlock.
masking: MaskSequence, optional
Masking to apply to the inputs.
{tabular_module_parameters}
"""
EMBEDDING_MODULE_CLASS = SequenceEmbeddingFeatures
def __init__(
self,
continuous_layer: Optional[TabularBlock] = None,
categorical_layer: Optional[TabularBlock] = None,
text_embedding_layer: Optional[TabularBlock] = None,
projection_block: Optional[Block] = None,
masking: Optional[MaskSequence] = None,
pre: Optional[TabularTransformationType] = None,
post: Optional[TabularTransformationType] = None,
aggregation: Optional[TabularAggregationType] = None,
name=None,
**kwargs
):
super().__init__(
continuous_layer=continuous_layer,
categorical_layer=categorical_layer,
text_embedding_layer=text_embedding_layer,
pre=pre,
post=post,
aggregation=aggregation,
name=name,
**kwargs,
)
self.projection_block = projection_block
self.set_masking(masking)
[docs] @classmethod
def from_schema( # type: ignore
cls,
schema: Schema,
continuous_tags=(Tag.CONTINUOUS,),
categorical_tags=(Tag.CATEGORICAL,),
aggregation=None,
max_sequence_length=None,
continuous_projection=None,
projection=None,
d_output=None,
masking=None,
**kwargs
) -> "TabularSequenceFeatures":
"""Instantiates ``TabularFeatures`` from a ``DatasetSchema``
Parameters
----------
schema : DatasetSchema
Dataset schema
continuous_tags : Optional[Union[DefaultTags, list, str]], optional
Tags to filter the continuous features, by default Tag.CONTINUOUS
categorical_tags : Optional[Union[DefaultTags, list, str]], optional
Tags to filter the categorical features, by default Tag.CATEGORICAL
aggregation : Optional[str], optional
Feature aggregation option, by default None
automatic_build : bool, optional
Automatically infers input size from features, by default True
max_sequence_length : Optional[int], optional
Maximum sequence length for list features by default None
continuous_projection : Optional[Union[List[int], int]], optional
If set, concatenate all numerical features and project them by a number of MLP layers
The argument accepts a list with the dimensions of the MLP layers, by default None
projection: Optional[torch.nn.Module, BuildableBlock], optional
If set, project the aggregated embeddings vectors into hidden dimension vector space,
by default None
d_output: Optional[int], optional
If set, init a MLPBlock as projection module to project embeddings vectors,
by default None
masking: Optional[Union[str, MaskSequence]], optional
If set, Apply masking to the input embeddings and compute masked labels, It requires
a categorical_module including an item_id column, by default None
Returns
-------
TabularFeatures:
Returns ``TabularFeatures`` from a dataset schema"""
output = super().from_schema(
schema=schema,
continuous_tags=continuous_tags,
categorical_tags=categorical_tags,
aggregation=aggregation,
max_sequence_length=max_sequence_length,
continuous_projection=continuous_projection,
**kwargs,
)
if d_output and projection:
raise ValueError("You cannot specify both d_output and projection at the same time")
if (projection or masking or d_output) and not aggregation:
# TODO: print warning here for clarity
output.set_aggregation("concat")
# hidden_size = output.output_size()
if d_output and not projection:
projection = MLPBlock([d_output])
if projection:
output.projection_block = projection
if isinstance(masking, str):
masking = masking_registry.parse(masking)(**kwargs)
if masking and not getattr(output, "item_id", None):
raise ValueError("For masking a categorical_module is required including an item_id.")
output.set_masking(masking)
return output
[docs] def project_continuous_features(self, dimensions):
if isinstance(dimensions, int):
dimensions = [dimensions]
continuous = self.continuous_layer
continuous.set_aggregation("concat")
continuous = SequentialBlock(
[continuous, MLPBlock(dimensions), AsTabular("continuous_projection")]
)
self.to_merge["continuous_layer"] = continuous
return self
[docs] def call(self, inputs, training=True):
outputs = super(TabularSequenceFeatures, self).call(inputs)
if self.masking or self.projection_block:
outputs = self.aggregation(outputs)
if self.projection_block:
outputs = self.projection_block(outputs)
if self.masking:
outputs = self.masking(
outputs, item_ids=self.to_merge["categorical_layer"].item_seq, training=training
)
return outputs
[docs] def compute_call_output_shape(self, input_shape):
output_shapes = {}
for layer in self.merge_values:
output_shapes.update(layer.compute_output_shape(input_shape))
return output_shapes
[docs] def compute_output_shape(self, input_shapes):
output_shapes = super().compute_output_shape(input_shapes)
if self.projection_block:
output_shapes = self.projection_block.compute_output_shape(output_shapes)
return output_shapes
@property
def masking(self):
return self._masking
[docs] def set_masking(self, value):
self._masking = value
@property
def item_id(self) -> Optional[str]:
if "categorical_layer" in self.to_merge_dict:
return getattr(self.to_merge_dict["categorical_layer"], "item_id", None)
return None
@property
def item_embedding_table(self):
if "categorical_layer" in self.to_merge_dict:
return getattr(self.to_merge_dict["categorical_layer"], "item_embedding_table", None)
return None
[docs] def get_config(self):
config = super().get_config()
config = tf_utils.maybe_serialize_keras_objects(
self, config, ["projection_block", "masking"]
)
return config
[docs] @classmethod
def from_config(cls, config, **kwargs):
config = tf_utils.maybe_deserialize_keras_objects(config, ["projection_block", "masking"])
return super().from_config(config)
TabularFeaturesType = Union[TabularSequenceFeatures, TabularFeatures]