alibi_detect.models.tensorflow.embedding module

class alibi_detect.models.tensorflow.embedding.TransformerEmbedding(model_name_or_path, embedding_type, layers=None)[source]

Bases: Model

__init__(model_name_or_path, embedding_type, layers=None)[source]

Extract text embeddings from transformer models.

  • model_name_or_path (str) – Name of or path to the model.

  • embedding_type (str) –

    Type of embedding to extract. Needs to be one of pooler_output, last_hidden_state, hidden_state or hidden_state_cls.

    From the HuggingFace documentation:

    • pooler_output

      Last layer hidden-state of the first token of the sequence (classification token) further processed by a Linear layer and a Tanh activation function. The Linear layer weights are trained from the next sentence prediction (classification) objective during pre-training. This output is usually not a good summary of the semantic content of the input, you’re often better with averaging or pooling the sequence of hidden-states for the whole input sequence.

    • last_hidden_state

      Sequence of hidden-states at the output of the last layer of the model.

    • hidden_state

      Hidden states of the model at the output of each layer.

    • hidden_state_cls

      See hidden_state but use the CLS token output.

  • layers (Optional[List[int]]) – If “hidden_state” or “hidden_state_cls” is used as embedding type, layers has to be a list with int’s referring to the hidden layers used to extract the embedding.

Return type:


alibi_detect.models.tensorflow.embedding.hidden_state_embedding(hidden_states, layers, use_cls, reduce_mean=True)[source]

Extract embeddings from hidden attention state layers.

  • hidden_states (Tensor) – Attention hidden states in the transformer model.

  • layers (List[int]) – List of layers to use for the embedding.

  • use_cls (bool) – Whether to use the next sentence token (CLS) to extract the embeddings.

  • reduce_mean (bool) – Whether to take the mean of the output tensor.

Return type:



Tensor with embeddings.