Class: Transformers::Bert::BertEmbeddings

Inherits:
Torch::NN::Module
  • Object
show all
Defined in:
lib/transformers/models/bert/modeling_bert.rb

Instance Method Summary collapse

Constructor Details

#initialize(config) ⇒ BertEmbeddings

Returns a new instance of BertEmbeddings.



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# File 'lib/transformers/models/bert/modeling_bert.rb', line 19

def initialize(config)
  super()
  @word_embeddings = Torch::NN::Embedding.new(config.vocab_size, config.hidden_size, padding_idx: config.pad_token_id)
  @position_embeddings = Torch::NN::Embedding.new(config.max_position_embeddings, config.hidden_size)
  @token_type_embeddings = Torch::NN::Embedding.new(config.type_vocab_size, config.hidden_size)

  @LayerNorm = Torch::NN::LayerNorm.new(config.hidden_size, eps: config.layer_norm_eps)
  @dropout = Torch::NN::Dropout.new(p: config.hidden_dropout_prob)
  # position_ids (1, len position emb) is contiguous in memory and exported when serialized
  @position_embedding_type = config.position_embedding_type || "absolute"
  register_buffer(
    "position_ids", Torch.arange(config.max_position_embeddings).expand([1, -1]), persistent: false
  )
  register_buffer(
    "token_type_ids", Torch.zeros(position_ids.size, dtype: Torch.long), persistent: false
  )
end

Instance Method Details

#forward(input_ids: nil, token_type_ids: nil, position_ids: nil, inputs_embeds: nil, past_key_values_length: 0) ⇒ Object 



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# File 'lib/transformers/models/bert/modeling_bert.rb', line 37

def forward(
  input_ids: nil,
  token_type_ids: nil,
  position_ids: nil,
  inputs_embeds: nil,
  past_key_values_length: 0
)
  if !input_ids.nil?
    input_shape = input_ids.size
  else
    input_shape = inputs_embeds.size[...-1]
  end

  seq_length = input_shape[1]

  if position_ids.nil?
    position_ids = @position_ids[0.., past_key_values_length...(seq_length + past_key_values_length)]
  end

  # Setting the token_type_ids to the registered buffer in constructor where it is all zeros, which usually occurs
  # when its auto-generated, registered buffer helps users when tracing the model without passing token_type_ids, solves
  # issue #5664
  if token_type_ids.nil?
    raise Todo
  end

  if inputs_embeds.nil?
    inputs_embeds = @word_embeddings.(input_ids)
  end
  token_type_embeddings = @token_type_embeddings.(token_type_ids)

  embeddings = inputs_embeds + token_type_embeddings
  if @position_embedding_type == "absolute"
    position_embeddings = @position_embeddings.(position_ids)
    embeddings += position_embeddings
  end
  embeddings = @LayerNorm.(embeddings)
  embeddings = @dropout.(embeddings)
  embeddings
end