tf.nn.embedding_lookup
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Looks up ids
in a list of embedding tensors.
tf.nn.embedding_lookup( params, ids, partition_strategy='mod', name=None, validate_indices=True, max_norm=None )
This function is used to perform parallel lookups on the list of tensors in params
. It is a generalization of tf.gather
, where params
is interpreted as a partitioning of a large embedding tensor. params
may be a PartitionedVariable
as returned by using tf.compat.v1.get_variable()
with a partitioner.
If len(params) > 1
, each element id
of ids
is partitioned between the elements of params
according to the partition_strategy
. In all strategies, if the id space does not evenly divide the number of partitions, each of the first (max_id + 1) % len(params)
partitions will be assigned one more id.
If partition_strategy
is "mod"
, we assign each id to partition p = id % len(params)
. For instance, 13 ids are split across 5 partitions as: [[0, 5, 10], [1, 6, 11], [2, 7, 12], [3, 8], [4, 9]]
If partition_strategy
is "div"
, we assign ids to partitions in a contiguous manner. In this case, 13 ids are split across 5 partitions as: [[0, 1, 2], [3, 4, 5], [6, 7, 8], [9, 10], [11, 12]]
The results of the lookup are concatenated into a dense tensor. The returned tensor has shape shape(ids) + shape(params)[1:]
.
Args | |
---|---|
params | A single tensor representing the complete embedding tensor, or a list of P tensors all of same shape except for the first dimension, representing sharded embedding tensors. Alternatively, a PartitionedVariable , created by partitioning along dimension 0. Each element must be appropriately sized for the given partition_strategy . |
ids | A Tensor with type int32 or int64 containing the ids to be looked up in params . |
partition_strategy | A string specifying the partitioning strategy, relevant if len(params) > 1 . Currently "div" and "mod" are supported. Default is "mod" . |
name | A name for the operation (optional). |
validate_indices | DEPRECATED. If this operation is assigned to CPU, values in indices are always validated to be within range. If assigned to GPU, out-of-bound indices result in safe but unspecified behavior, which may include raising an error. |
max_norm | If not None , each embedding is clipped if its l2-norm is larger than this value. |
Returns | |
---|---|
A Tensor with the same type as the tensors in params . |
Raises | |
---|---|
ValueError | If params is empty. |
© 2020 The TensorFlow Authors. All rights reserved.
Licensed under the Creative Commons Attribution License 3.0.
Code samples licensed under the Apache 2.0 License.
https://www.tensorflow.org/versions/r1.15/api_docs/python/tf/nn/embedding_lookup