haystack/tutorials/Tutorial12_LFQA.py
Sara Zan 91cafb49bb
Improve tutorials' output (#1694)
* Modify __str__ and __repr__ for Document and Answer

* Rename QueryClassifier in Tutorial11

* Improve the output of tutorial1

* Make the output of Tutorial8 a bit less dense

* Add a print_questions util to print the output of question generating pipelines

* Replace custom printing with the new utility in Tutorial13

* Ensure all output is printed with minimal details in Tutorial14 and add some titles

* Minor change to print_answers

* Make tutorial3's output the same as tutorial1

* Add __repr__ to Answer and fix to_dict()

* Fix a bug in the Document and Answer's __str__ method

* Improve print_answers, print_documents and print_questions

* Using print_answers in Tutorial7 and fixing typo in the utils

* Remove duplicate line in Tutorial12

* Use print_answers in Tutorial4

* Add explanation of what the documents in the output of the basic QA pipeline are

* Move the fields constant into print_answers

* Normalize all 'minimal' to 'minimum' (they were mixed up)

* Improve the sample output to include all fields from Document and Answer

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
2021-11-09 15:09:26 +01:00

102 lines
4.3 KiB
Python

from haystack.utils import convert_files_to_dicts, fetch_archive_from_http, clean_wiki_text
from haystack.nodes import Seq2SeqGenerator
def tutorial12_lfqa():
"""
Document Store:
FAISS is a library for efficient similarity search on a cluster of dense vectors.
The `FAISSDocumentStore` uses a SQL(SQLite in-memory be default) database under-the-hood
to store the document text and other meta data. The vector embeddings of the text are
indexed on a FAISS Index that later is queried for searching answers.
The default flavour of FAISSDocumentStore is "Flat" but can also be set to "HNSW" for
faster search at the expense of some accuracy. Just set the faiss_index_factor_str argument in the constructor.
For more info on which suits your use case: https://github.com/facebookresearch/faiss/wiki/Guidelines-to-choose-an-index
"""
from haystack.document_stores.faiss import FAISSDocumentStore
document_store = FAISSDocumentStore(vector_dim=128, faiss_index_factory_str="Flat")
"""
Cleaning & indexing documents:
Similarly to the previous tutorials, we download, convert and index some Game of Thrones articles to our DocumentStore
"""
# Let's first get some files that we want to use
doc_dir = "data/article_txt_got"
s3_url = "https://s3.eu-central-1.amazonaws.com/deepset.ai-farm-qa/datasets/documents/wiki_gameofthrones_txt.zip"
fetch_archive_from_http(url=s3_url, output_dir=doc_dir)
# Convert files to dicts
dicts = convert_files_to_dicts(dir_path=doc_dir, clean_func=clean_wiki_text, split_paragraphs=True)
# Now, let's write the dicts containing documents to our DB.
document_store.write_documents(dicts)
"""
Initalize Retriever and Reader/Generator:
We use a `RetribertRetriever` and we invoke `update_embeddings` to index the embeddings of documents in the `FAISSDocumentStore`
"""
from haystack.nodes import EmbeddingRetriever
retriever = EmbeddingRetriever(document_store=document_store,
embedding_model="yjernite/retribert-base-uncased",
model_format="retribert")
document_store.update_embeddings(retriever)
"""Before we blindly use the `RetribertRetriever` let's empirically test it to make sure a simple search indeed finds the relevant documents."""
from haystack.utils import print_documents
from haystack.pipelines import DocumentSearchPipeline
p_retrieval = DocumentSearchPipeline(retriever)
res = p_retrieval.run(
query="Tell me something about Arya Stark?",
params={"Retriever": {"top_k": 1}}
)
print_documents(res, max_text_len=512)
"""
Similar to previous Tutorials we now initalize our reader/generator.
Here we use a `Seq2SeqGenerator` with the *yjernite/bart_eli5* model (see: https://huggingface.co/yjernite/bart_eli5)
"""
generator = Seq2SeqGenerator(model_name_or_path="yjernite/bart_eli5")
"""
Pipeline:
With a Haystack `Pipeline` you can stick together your building blocks to a search pipeline.
Under the hood, `Pipelines` are Directed Acyclic Graphs (DAGs) that you can easily customize for your own use cases.
To speed things up, Haystack also comes with a few predefined Pipelines. One of them is the `GenerativeQAPipeline` that combines a retriever and a reader/generator to answer our questions.
You can learn more about `Pipelines` in the [docs](https://haystack.deepset.ai/docs/latest/pipelinesmd).
"""
from haystack.pipelines import GenerativeQAPipeline
pipe = GenerativeQAPipeline(generator, retriever)
"""Voilà! Ask a question!"""
query_1 = "Why did Arya Stark's character get portrayed in a television adaptation?"
result_1 = pipe.run(query=query_1, params={"Retriever": {"top_k": 1}})
print(f"Query: {query_1}")
print(f"Answer: {result_1['answers'][0]}")
print()
query_2 = "What kind of character does Arya Stark play?"
result_2 = pipe.run(query=query_2, params={"Retriever": {"top_k": 1}})
print(f"Query: {query_2}")
print(f"Answer: {result_2['answers'][0]}")
print()
if __name__ == "__main__":
tutorial12_lfqa()
# This Haystack script was made with love by deepset in Berlin, Germany
# Haystack: https://github.com/deepset-ai/haystack
# deepset: https://deepset.ai/