open-webui/backend/open_webui/apps/retrieval/models/colbert.py

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2024-09-28 00:23:09 +00:00
import os
import torch
import numpy as np
from colbert.infra import ColBERTConfig
from colbert.modeling.checkpoint import Checkpoint
class ColBERT:
def __init__(self, name, **kwargs) -> None:
print("ColBERT: Loading model", name)
self.device = "cuda" if torch.cuda.is_available() else "cpu"
DOCKER = kwargs.get("env") == "docker"
if DOCKER:
# This is a workaround for the issue with the docker container
# where the torch extension is not loaded properly
# and the following error is thrown:
# /root/.cache/torch_extensions/py311_cpu/segmented_maxsim_cpp/segmented_maxsim_cpp.so: cannot open shared object file: No such file or directory
lock_file = (
"/root/.cache/torch_extensions/py311_cpu/segmented_maxsim_cpp/lock"
)
if os.path.exists(lock_file):
os.remove(lock_file)
self.ckpt = Checkpoint(
name,
colbert_config=ColBERTConfig(model_name=name),
).to(self.device)
pass
def calculate_similarity_scores(self, query_embeddings, document_embeddings):
query_embeddings = query_embeddings.to(self.device)
document_embeddings = document_embeddings.to(self.device)
# Validate dimensions to ensure compatibility
if query_embeddings.dim() != 3:
raise ValueError(
f"Expected query embeddings to have 3 dimensions, but got {query_embeddings.dim()}."
)
if document_embeddings.dim() != 3:
raise ValueError(
f"Expected document embeddings to have 3 dimensions, but got {document_embeddings.dim()}."
)
if query_embeddings.size(0) not in [1, document_embeddings.size(0)]:
raise ValueError(
"There should be either one query or queries equal to the number of documents."
)
# Transpose the query embeddings to align for matrix multiplication
transposed_query_embeddings = query_embeddings.permute(0, 2, 1)
# Compute similarity scores using batch matrix multiplication
computed_scores = torch.matmul(document_embeddings, transposed_query_embeddings)
# Apply max pooling to extract the highest semantic similarity across each document's sequence
maximum_scores = torch.max(computed_scores, dim=1).values
# Sum up the maximum scores across features to get the overall document relevance scores
final_scores = maximum_scores.sum(dim=1)
normalized_scores = torch.softmax(final_scores, dim=0)
return normalized_scores.detach().cpu().numpy().astype(np.float32)
def predict(self, sentences):
query = sentences[0][0]
docs = [i[1] for i in sentences]
# Embedding the documents
embedded_docs = self.ckpt.docFromText(docs, bsize=32)[0]
# Embedding the queries
embedded_queries = self.ckpt.queryFromText([query], bsize=32)
embedded_query = embedded_queries[0]
# Calculate retrieval scores for the query against all documents
scores = self.calculate_similarity_scores(
embedded_query.unsqueeze(0), embedded_docs
)
return scores