# View Source Bumblebee.Text.Roberta(Bumblebee v0.2.0)

RoBERTa model family.

## architectures Architectures

• :base - plain RoBERTa without any head on top

• :for_masked_language_modeling - RoBERTa with a language modeling head. The head returns logits for each token in the original sequence

• :for_sequence_classification - RoBERTa with a sequence classification head. The head returns logits corresponding to possible classes

• :for_token_classification - RoBERTa with a token classification head. The head returns logits for each token in the original sequence

• :for_question_answering - RoBERTa with a span classification head. The head returns logits for the span start and end positions

• :for_multiple_choice - RoBERTa with a multiple choice prediction head. Each input in the batch consists of several sequences to choose from and the model returns logits corresponding to those choices

• :for_causal_language_modeling - RoBERTa working as a decoder with a language modeling head. The head returns logits for each token in the original sequence

## inputs Inputs

• "input_ids" - {batch_size, sequence_length}

Indices of input sequence tokens in the vocabulary.

• "attention_mask" - {batch_size, sequence_length}

Mask indicating which tokens to attend to. This is used to ignore padding tokens, which are added when processing a batch of sequences with different length.

• "token_type_ids" - {batch_size, sequence_length}

Mask distinguishing groups in the input sequence. This is used in when the input sequence is a semantically a pair of sequences.

• "position_ids" - {batch_size, sequence_length}

Indices of positions of each input sequence tokens in the position embeddings.

• "attention_head_mask" - {num_blocks, num_attention_heads}

Mask to nullify selected heads of the self-attention blocks in the encoder.

### exceptions Exceptions

The :for_multiple_choice model accepts groups of sequences, so the expected sequence shape is {batch_size, num_choices, sequence_length}.

The :for_causal_language_modeling model is a decoder and accepts the following additional inputs: "encoder_hidden_state", "encoder_attention_mask", "cross_attention_head_mask", "cache".

## configuration Configuration

• :vocab_size - the vocabulary size of the token embedding. This corresponds to the number of distinct tokens that can be represented in model input and output . Defaults to 30522

• :max_positions - the vocabulary size of the position embedding. This corresponds to the maximum sequence length that this model can process. Typically this is set to a large value just in case, such as 512, 1024 or 2048 . Defaults to 512

• :max_token_types - the vocabulary size of the token type embedding (also referred to as segment embedding). This corresponds to how many different token groups can be distinguished in the input . Defaults to 2

• :hidden_size - the dimensionality of hidden layers. Defaults to 768

• :num_blocks - the number of Transformer blocks in the encoder. Defaults to 12

• :num_attention_heads - the number of attention heads for each attention layer in the encoder. Defaults to 12

• :intermediate_size - the dimensionality of the intermediate layer in the transformer feed-forward network (FFN) in the encoder. Defaults to 3072

• :activation - the activation function. Defaults to :gelu

• :dropout_rate - the dropout rate for embedding and encoder. Defaults to 0.1

• :attention_dropout_rate - the dropout rate for attention weights. Defaults to 0.1

• :classifier_dropout_rate - the dropout rate for the classification head. If not specified, the value of :dropout_rate is used instead

• :layer_norm_epsilon - the epsilon used by the layer normalization layers. Defaults to 1.0e-12

• :initializer_range - the standard deviation of the normal initializer used for initializing kernel parameters. Defaults to 0.02

• :output_hidden_states - whether the model should return all hidden states. Defaults to false

• :output_attentions - whether the model should return all attentions. Defaults to false

• :num_labels - the number of labels to use in the last layer for the classification task. Defaults to 2

• :id_to_label - a map from class index to label. Defaults to %{}

• :use_cross_attention - whether cross-attention layers should be added to the model.This is only relevant for decoder models. Defaults to false