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from sentence_transformers import SentenceTransformer, CrossEncoder, util | |
from torch import tensor as torch_tensor | |
from datasets import load_dataset | |
from langchain.llms import OpenAI | |
from langchain.docstore.document import Document | |
from langchain.chains.question_answering import load_qa_chain | |
from langchain.chains.qa_with_sources import load_qa_with_sources_chain | |
from langchain.prompts import PromptTemplate | |
"""# import models""" | |
bi_encoder = SentenceTransformer('multi-qa-MiniLM-L6-cos-v1') | |
bi_encoder.max_seq_length = 256 #Truncate long passages to 256 tokens | |
#The bi-encoder will retrieve top_k documents. We use a cross-encoder, to re-rank the results list to improve the quality | |
cross_encoder = CrossEncoder('cross-encoder/ms-marco-MiniLM-L-6-v2') | |
"""# import datasets""" | |
dataset = load_dataset("gfhayworth/hack_policy", split='train') | |
mypassages = list(dataset.to_pandas()['psg']) | |
dataset_embed = load_dataset("gfhayworth/hack_policy_embed", split='train') | |
dataset_embed_pd = dataset_embed.to_pandas() | |
mycorpus_embeddings = torch_tensor(dataset_embed_pd.values) | |
def search(query, passages = mypassages, doc_embedding = mycorpus_embeddings, top_k=20, top_n = 1): | |
question_embedding = bi_encoder.encode(query, convert_to_tensor=True) | |
question_embedding = question_embedding #.cuda() | |
hits = util.semantic_search(question_embedding, doc_embedding, top_k=top_k) | |
hits = hits[0] # Get the hits for the first query | |
##### Re-Ranking ##### | |
cross_inp = [[query, passages[hit['corpus_id']]] for hit in hits] | |
cross_scores = cross_encoder.predict(cross_inp) | |
# Sort results by the cross-encoder scores | |
for idx in range(len(cross_scores)): | |
hits[idx]['cross-score'] = cross_scores[idx] | |
hits = sorted(hits, key=lambda x: x['cross-score'], reverse=True) | |
predictions = hits[:top_n] | |
return predictions | |
# for hit in hits[0:3]: | |
# print("\t{:.3f}\t{}".format(hit['cross-score'], mypassages[hit['corpus_id']].replace("\n", " "))) | |
def get_text_fmt(qry, passages = mypassages, doc_embedding=mycorpus_embeddings): | |
predictions = search(qry, passages = passages, doc_embedding = doc_embedding, top_n=5, ) | |
prediction_text = [] | |
for hit in predictions: | |
page_content = passages[hit['corpus_id']] | |
metadata = {"source": hit['corpus_id']} | |
result = Document(page_content=page_content, metadata=metadata) | |
prediction_text.append(result) | |
return prediction_text | |
template = """You are a friendly AI assistant for the insurance company Humana. Given the following extracted parts of a long document and a question, create a succinct final answer. | |
If you don't know the answer, just say that you don't know. Don't try to make up an answer. | |
If the question is not about Humana, politely inform them that you are tuned to only answer questions about Humana. | |
QUESTION: {question} | |
========= | |
{context} | |
========= | |
FINAL ANSWER:""" | |
PROMPT = PromptTemplate(template=template, input_variables=["context", "question"]) | |
chain_qa = load_qa_chain(OpenAI(temperature=0), chain_type="stuff", prompt=PROMPT) | |
def get_llm_response(message): | |
mydocs = get_text_fmt(message) | |
response = chain_qa.run(input_documents=mydocs, question=message) | |
return response | |
def chat(message, history): | |
history = history or [] | |
message = message.lower() | |
response = get_llm_response(message) | |
history.append((message, response)) | |
return history, history | |