Update app.py

app.py

@@ -153,7 +153,7 @@ def retrieve_and_query(query, retriever_engine):
     )
     qa_tmpl = PromptTemplate(qa_tmpl_str)
 
-    llm = OpenAI(model="gpt-4o", temperature=0)
+    llm = OpenAI(model="gpt-4o-mini", temperature=0)
     response_synthesizer = get_response_synthesizer(response_mode="refine", text_qa_template=qa_tmpl, llm=llm)
 
     response = response_synthesizer.synthesize(query, nodes=retrieval_results)