doc2query/msmarco-portuguese-mt5-base-v1

This is a doc2query model based on mT5 (also known as docT5query).

It can be used for:

• Document expansion: You generate for your paragraphs 20-40 queries and index the paragraphs and the generates queries in a standard BM25 index like Elasticsearch, OpenSearch, or Lucene. The generated queries help to close the lexical gap of lexical search, as the generate queries contain synonyms. Further, it re-weights words giving important words a higher weight even if they appear seldomn in a paragraph. In our BEIR paper we showed that BM25+docT5query is a powerful search engine. In the BEIR repository we have an example how to use docT5query with Pyserini.
• Domain Specific Training Data Generation: It can be used to generate training data to learn an embedding model. In our GPL-Paper / GPL Example on SBERT.net we have an example how to use the model to generate (query, text) pairs for a given collection of unlabeled texts. These pairs can then be used to train powerful dense embedding models.

Usage

from transformers import AutoTokenizer, AutoModelForSeq2SeqLM
import torch

model_name = 'doc2query/msmarco-portuguese-mt5-base-v1'
tokenizer = AutoTokenizer.from_pretrained(model_name)
model = AutoModelForSeq2SeqLM.from_pretrained(model_name)

text = "Python é uma linguagem de programação de alto nível, interpretada de script, imperativa, orientada a objetos, funcional, de tipagem dinâmica e forte. Foi lançada por Guido van Rossum em 1991. Atualmente, possui um modelo de desenvolvimento comunitário, aberto e gerenciado pela organização sem fins lucrativos Python Software Foundation. Apesar de várias partes da linguagem possuírem padrões e especificações formais, a linguagem, como um todo, não é formalmente especificada. O padrão de facto é a implementação CPython."


def create_queries(para):
    input_ids = tokenizer.encode(para, return_tensors='pt')
    with torch.no_grad():
        # Here we use top_k / top_k random sampling. It generates more diverse queries, but of lower quality
        sampling_outputs = model.generate(
            input_ids=input_ids,
            max_length=64,
            do_sample=True,
            top_p=0.95,
            top_k=10, 
            num_return_sequences=5
            )
        
        # Here we use Beam-search. It generates better quality queries, but with less diversity
        beam_outputs = model.generate(
            input_ids=input_ids, 
            max_length=64, 
            num_beams=5, 
            no_repeat_ngram_size=2, 
            num_return_sequences=5, 
            early_stopping=True
        )


    print("Paragraph:")
    print(para)
    
    print("\nBeam Outputs:")
    for i in range(len(beam_outputs)):
        query = tokenizer.decode(beam_outputs[i], skip_special_tokens=True)
        print(f'{i + 1}: {query}')

    print("\nSampling Outputs:")
    for i in range(len(sampling_outputs)):
        query = tokenizer.decode(sampling_outputs[i], skip_special_tokens=True)
        print(f'{i + 1}: {query}')

create_queries(text)

Note: model.generate() is non-deterministic for top_k/top_n sampling. It produces different queries each time you run it.

Training

This model fine-tuned google/mt5-base for 66k training steps (4 epochs on the 500k training pairs from MS MARCO). For the training script, see the train_script.py in this repository.

The input-text was truncated to 320 word pieces. Output text was generated up to 64 word pieces.

This model was trained on a (query, passage) from the mMARCO dataset.