nn_embedding_bag {torch}

Embedding bag module

Description

Computes sums, means or maxes of bags of embeddings, without instantiating the intermediate embeddings.

Usage

nn_embedding_bag(
  num_embeddings,
  embedding_dim,
  max_norm = NULL,
  norm_type = 2,
  scale_grad_by_freq = FALSE,
  mode = "mean",
  sparse = FALSE,
  include_last_offset = FALSE,
  padding_idx = NULL,
  .weight = NULL
)

Arguments

num_embeddings

(int): size of the dictionary of embeddings

embedding_dim

(int): the size of each embedding vector

max_norm

(float, optional): If given, each embedding vector with norm larger than max_norm is renormalized to have norm max_norm.

norm_type

(float, optional): The p of the p-norm to compute for the max_norm option. Default 2

scale_grad_by_freq

(boolean, optional): If given, this will scale gradients by the inverse of frequency of the words in the mini-batch. Default False.

mode

(string, optional): "sum", "mean" or "max". Specifies the way to reduce the bag. "sum" computes the weighted sum, taking per_sample_weights into consideration. "mean" computes the average of the values in the bag, "max" computes the max value over each bag.

sparse

(bool, optional): If True, gradient w.r.t. weight matrix will be a sparse tensor. See Notes for more details regarding sparse gradients.

include_last_offset

(bool, optional): if True, offsets has one additional element, where the last element is equivalent to the size of indices. This matches the CSR format.

padding_idx

(int, optional): If given, pads the output with the embedding vector at padding_idx (initialized to zeros) whenever it encounters the index.

.weight

(Tensor, optional) embeddings weights (in case you want to set it manually)

Attributes

• weight (Tensor): the learnable weights of the module of shape (num_embeddings, embedding_dim) initialized from \mathcal{N}(0, 1)

Examples

if (torch_is_installed()) {
# an EmbeddingBag module containing 10 tensors of size 3
embedding_sum <- nn_embedding_bag(10, 3, mode = 'sum')
# a batch of 2 samples of 4 indices each
input <- torch_tensor(c(1, 2, 4, 5, 4, 3, 2, 9), dtype = torch_long())
offsets <- torch_tensor(c(0, 4), dtype = torch_long())
embedding_sum(input, offsets)
# example with padding_idx
embedding_sum <- nn_embedding_bag(10, 3, mode = 'sum', padding_idx = 1)
input <- torch_tensor(c(2, 2, 2, 2, 4, 3, 2, 9), dtype = torch_long())
offsets <- torch_tensor(c(0, 4), dtype = torch_long())
embedding_sum(input, offsets)
# An EmbeddingBag can be loaded from an Embedding like so
embedding <- nn_embedding(10, 3, padding_idx = 2)
embedding_sum <- nn_embedding_bag$from_pretrained(embedding$weight,
                                                 padding_idx = embedding$padding_idx,
                                                 mode='sum')
}