added reranker

app.py

@@ -1,6 +1,7 @@
 import spaces
 import gradio as gr
 from llama_index.embeddings.huggingface import HuggingFaceEmbedding
+from llama_index.core.postprocessor import SentenceTransformerRerank
 from llama_index.core import (
     StorageContext,
     load_index_from_storage, Settings,
@@ -29,6 +30,12 @@ storage_context = StorageContext.from_defaults(persist_dir=PERSIST_DIR)
 index = load_index_from_storage(storage_context)
 query_engine = index.as_query_engine()
 
+rerank = SentenceTransformerRerank(
+    model="BAAI/bge-reranker-large", top_n=5  # Note here
+)
+
+query_engine = index.as_query_engine(streaming=True, similarity_top_k=1, node_postprocessors=[rerank])
+
 
 @spaces.GPU
 def chatbot_response(message, history):