Rui Melo
initial commit
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metadata
language:
  - pt
thumbnail: Portugues SBERT for the Legal Domain
pipeline_tag: sentence-similarity
tags:
  - sentence-transformers
  - sentence-similarity
  - transformers
datasets:
  - assin
  - assin2
  - stsb_multi_mt
widget:
  - source_sentence: O advogado apresentou as provas ao juíz.
    sentences:
      - O juíz leu as provas.
      - O juíz leu o recurso.
      - O juíz atirou uma pedra.
    example_title: Example 1
metrics:
  - bleu

rufimelo/Legal-SBERTimbau-sts-base-ma

This is a sentence-transformers model: It maps sentences & paragraphs to a 768 dimensional dense vector space and can be used for tasks like clustering or semantic search. rufimelo/rufimelo/Legal-SBERTimbau-sts-base-ma is based on Legal-BERTimbau-base which derives from BERTimbau alrge. It is adapted to the Portuguese legal domain and trained for STS on portuguese datasets.

Usage (Sentence-Transformers)

Using this model becomes easy when you have sentence-transformers installed:

pip install -U sentence-transformers

Then you can use the model like this:

from sentence_transformers import SentenceTransformer
sentences = ["Isto é um exemplo", "Isto é um outro exemplo"]

model = SentenceTransformer('rufimelo/Legal-SBERTimbau-sts-base-ma')
embeddings = model.encode(sentences)
print(embeddings)

Usage (HuggingFace Transformers)

from transformers import AutoTokenizer, AutoModel
import torch


#Mean Pooling - Take attention mask into account for correct averaging
def mean_pooling(model_output, attention_mask):
    token_embeddings = model_output[0] #First element of model_output contains all token embeddings
    input_mask_expanded = attention_mask.unsqueeze(-1).expand(token_embeddings.size()).float()
    return torch.sum(token_embeddings * input_mask_expanded, 1) / torch.clamp(input_mask_expanded.sum(1), min=1e-9)


# Sentences we want sentence embeddings for
sentences = ['This is an example sentence', 'Each sentence is converted']

# Load model from HuggingFace Hub
tokenizer = AutoTokenizer.from_pretrained('rufimelo/Legal-SBERTimbau-sts-base-ma')
model = AutoModel.from_pretrained('rufimelo/Legal-SBERTimbau-sts-base-ma')

# Tokenize sentences
encoded_input = tokenizer(sentences, padding=True, truncation=True, return_tensors='pt')

# Compute token embeddings
with torch.no_grad():
    model_output = model(**encoded_input)

# Perform pooling. In this case, mean pooling.
sentence_embeddings = mean_pooling(model_output, encoded_input['attention_mask'])

print("Sentence embeddings:")
print(sentence_embeddings)

Evaluation Results STS

Model Dataset PearsonCorrelation
Legal-SBERTimbau-sts-large Assin 0.76629
Legal-SBERTimbau-sts-large Assin2 0.82357
Legal-SBERTimbau-sts-base Assin 0.71457
Legal-SBERTimbau-sts-base Assin2 0.73545
Legal-SBERTimbau-sts-large-v2 Assin 0.76299
Legal-SBERTimbau-sts-large-v2 Assin2 0.81121
Legal-SBERTimbau-sts-large-v2 stsb_multi_mt pt 0.81726
Legal-SBERTimbau-sts-base-ma Assin 0.74874
Legal-SBERTimbau-sts-base-ma Assin2 0.79532
Legal-SBERTimbau-sts-base-ma stsb_multi_mt pt 0.82254
---------------------------------------- ---------- ----------
paraphrase-multilingual-mpnet-base-v2 Assin 0.71457
paraphrase-multilingual-mpnet-base-v2 Assin2 0.79831
paraphrase-multilingual-mpnet-base-v2 stsb_multi_mt pt 0.83999
paraphrase-multilingual-mpnet-base-v2 Fine tuned with assin(s) Assin 0.77641
paraphrase-multilingual-mpnet-base-v2 Fine tuned with assin(s) Assin2 0.79831
paraphrase-multilingual-mpnet-base-v2 Fine tuned with assin(s) stsb_multi_mt pt 0.84575

Training

rufimelo/Legal-SBERTimbau-sts-base-ma is based on Legal-BERTimbau-base which derives from BERTimbau base.

Firstly, due to the lack of portuguese datasets, it was trained using multilingual knowledge distillation. For the Multilingual Knowledge Distillation process, the teacher model was 'sentence-transformers/paraphrase-xlm-r-multilingual-v1', the supposed supported language as English and the language to learn was portuguese.

It was trained for Semantic Textual Similarity, being submitted to a fine tuning stage with the assin, assin2 and stsb_multi_mt pt datasets.

Full Model Architecture

SentenceTransformer(
  (0): Transformer({'max_seq_length': 128, 'do_lower_case': False}) with Transformer model: BertModel 
  (1): Pooling({'word_embedding_dimension': 768, 'pooling_mode_cls_token': False, 'pooling_mode_mean_tokens': True, 'pooling_mode_max_tokens': False, 'pooling_mode_mean_sqrt_len_tokens': False, 'pooling_mode_weightedmean_tokens': False, 'pooling_mode_lasttoken': False})
)

Citing & Authors

If you use this work, please cite BERTimbau's work:

@inproceedings{souza2020bertimbau,
  author    = {F{\'a}bio Souza and
               Rodrigo Nogueira and
               Roberto Lotufo},
  title     = {{BERT}imbau: pretrained {BERT} models for {B}razilian {P}ortuguese},
  booktitle = {9th Brazilian Conference on Intelligent Systems, {BRACIS}, Rio Grande do Sul, Brazil, October 20-23 (to appear)},
  year      = {2020}
}