fix: error in faiss

app.py

@@ -25,6 +25,17 @@ def fetch_arxiv_papers(query, max_results=5):
 
 # Load FAISS index
 def load_faiss_index(index_file="faiss_index.index"):
+    import os
+    if not os.path.exists(index_file):
+        st.warning("FAISS index not found. Building index from scratch...")
+        # Import the build function from the other file
+        import faiss_index_index
+        
+        # Fetch some initial papers to build the index
+        initial_papers = faiss_index_index.fetch_arxiv_papers("autism research", max_results=100)
+        faiss_index_index.build_faiss_index(initial_papers, index_file)
+        st.success("FAISS index built successfully!")
+    
     return faiss.read_index(index_file)
 
 # RAG Pipeline