Bug when visualizing T5 models with generate

[salokr]

I tried to visualize the attention maps for the T5 model but have encountered issues while getting the plots.

I would like to emphasize few points:

• I have used model.generate because I don't have labels assumed in my real project and generate can also output attentions.
• I have also tried passing the input directly to model but that also doesn't works.

from transformers import T5Tokenizer, T5ForConditionalGeneration

tokenizer = T5Tokenizer.from_pretrained("google-t5/t5-small")
model = T5ForConditionalGeneration.from_pretrained("google-t5/t5-small")

input_ids = tokenizer("translate English to German: The house is wonderful.", return_tensors="pt").input_ids
outputs = model.generate(input_ids, output_attentions=True, return_dict_in_generate=True)

encoder_text = tokenizer.convert_ids_to_tokens(input_ids[0])
decoder_text = tokenizer.convert_ids_to_tokens(outputs.sequences[0])


from bertviz import model_view
model_view(
    encoder_attention=outputs.encoder_attentions,
    decoder_attention=outputs.decoder_attentions,
    cross_attention=outputs.cross_attentions,
    encoder_tokens= encoder_text,
    decoder_tokens = decoder_text
)

The error I am getting is:

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In[56], line 6
      2 decoder_text = tokenizer.convert_ids_to_tokens(outputs.sequences[0])#tokenizer.convert_ids_to_tokens(decoder_input_ids[0])
      5 from bertviz import model_view
----> 6 model_view(
      7     encoder_attention=outputs.encoder_attentions,
      8     decoder_attention=outputs.decoder_attentions,
      9     cross_attention=outputs.cross_attentions,
     10     encoder_tokens= encoder_text,
     11     decoder_tokens = decoder_text
     12 )

File /Volumes/x/envs/my_env/lib/python3.8/site-packages/bertviz/model_view.py:147, in model_view(attention, tokens, sentence_b_start, prettify_tokens, display_mode, encoder_attention, decoder_attention, cross_attention, encoder_tokens, decoder_tokens, include_layers, include_heads, html_action)
    145     if include_heads is None:
    146         include_heads = list(range(n_heads))
--> 147     decoder_attention = format_attention(decoder_attention, include_layers, include_heads)
    148     attn_data.append(
    149         {
    150             'name': 'Decoder',
   (...)
    154         }
    155     )
    156 if cross_attention is not None:

File /Volumes/x/envs/my_env/lib/python3.8/site-packages/bertviz/util.py:10, in format_attention(attention, layers, heads)
      7 squeezed = []
      8 for layer_attention in attention:
      9     # 1 x num_heads x seq_len x seq_len
---> 10     if len(layer_attention.shape) != 4:
     11         raise ValueError("The attention tensor does not have the correct number of dimensions. Make sure you set "
     12                          "output_attentions=True when initializing your model.")
     13     layer_attention = layer_attention.squeeze(0)

AttributeError: 'tuple' object has no attribute 'shape'

[nikhilajoshy]

Looks like outputs.decoder_attentions is not a list of tensors but a list of tuples in your case. Please check the data type of attention variables.