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Looks up ids
in a list of embedding tensors.
tf.compat.v1.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]]
If the input ids are ragged tensors, partition variables are not supported and
the partition strategy and the max_norm are ignored.
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 or a 'RaggedTensor' 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 or a 'RaggedTensor', depending on the input, with the same type
as the tensors in params .
|
Raises | |
---|---|
ValueError
|
If params is empty.
|