semantic-search / search_utils.py
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import numpy as np
import pandas as pd
import faiss
import zipfile
from pathlib import Path
from sentence_transformers import SentenceTransformer, util
import streamlit as st
class MetadataManager:
def __init__(self):
self.shard_dir = Path("metadata_shards")
self.shard_map = {}
self.loaded_shards = {}
self.total_docs = 0
self._ensure_unzipped()
self._build_shard_map()
def _ensure_unzipped(self):
"""Handle ZIP extraction automatically"""
if not self.shard_dir.exists():
zip_path = Path("metadata_shards.zip")
if zip_path.exists():
with zipfile.ZipFile(zip_path, 'r') as zip_ref:
zip_ref.extractall(self.shard_dir)
st.toast("πŸ“¦ Metadata shards extracted successfully!", icon="βœ…")
else:
st.error("❌ Missing metadata_shards.zip file!")
raise FileNotFoundError("Metadata ZIP file not found")
def _build_shard_map(self):
"""Create index range to shard mapping"""
self.total_docs = 0
for f in sorted(self.shard_dir.glob("*.parquet")):
parts = f.stem.split("_")
start = int(parts[1])
end = int(parts[2])
self.shard_map[(start, end)] = f.name
self.total_docs = max(self.total_docs, end + 1)
def get_metadata(self, global_indices):
"""Retrieve metadata for global indices"""
results = []
shard_groups = {}
# Organize indices by their respective shards
for idx in global_indices:
for (start, end), shard in self.shard_map.items():
if start <= idx <= end:
if shard not in shard_groups:
shard_groups[shard] = []
shard_groups[shard].append(idx - start)
break
# Load and process required shards
for shard, local_indices in shard_groups.items():
if shard not in self.loaded_shards:
self.loaded_shards[shard] = pd.read_parquet(
self.shard_dir / shard,
columns=["title", "summary", "source"]
)
results.append(self.loaded_shards[shard].iloc[local_indices])
return pd.concat(results).reset_index(drop=True)
class SemanticSearch:
def __init__(self):
self.shard_dir = Path("compressed_shards")
self.model = None
self.index_shards = []
self.metadata_mgr = MetadataManager()
self.shard_sizes = []
@st.cache_resource
def load_model(_self):
return SentenceTransformer('all-MiniLM-L6-v2')
def initialize_system(self):
self.model = self.load_model()
self._load_faiss_shards()
def _load_faiss_shards(self):
"""Load all FAISS index shards"""
self.shard_sizes = []
for shard_path in sorted(self.shard_dir.glob("*.index")):
index = faiss.read_index(str(shard_path))
self.index_shards.append(index)
self.shard_sizes.append(index.ntotal)
def _global_index(self, shard_idx, local_idx):
"""Convert local index to global index"""
return sum(self.shard_sizes[:shard_idx]) + local_idx
def search(self, query, top_k=5):
"""Main search functionality"""
query_embedding = self.model.encode([query], convert_to_numpy=True)
all_distances = []
all_global_indices = []
# Search across all shards
for shard_idx, index in enumerate(self.index_shards):
distances, indices = index.search(query_embedding, top_k)
global_indices = [self._global_index(shard_idx, idx) for idx in indices[0]]
all_distances.extend(distances[0])
all_global_indices.extend(global_indices)
# Process and format results
results = self.metadata_mgr.get_metadata(all_global_indices)
results['similarity'] = 1 - (np.array(all_distances) / 2) # Convert L2 to cosine
return results.sort_values('similarity', ascending=False).head(top_k)