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Looks up ids
in a list of embedding tensors.
tf.nn.embedding_lookup(
params, ids, max_norm=None, name=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.
The partition_strategy
is always "div"
currently. This means that we
assign ids to partitions in a contiguous manner. For instance, 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:]
.
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 'div' partition_strategy
.ids
: A Tensor
with type int32
or int64
containing the ids to be looked
up in params
.max_norm
: If not None
, each embedding is clipped if its l2-norm is larger
than this value.name
: A name for the operation (optional).A Tensor
with the same type as the tensors in params
.
ValueError
: If params
is empty.