update chain to use open weights open-mistral-7b chat model

src/chain.py

@@ -15,7 +15,8 @@ class GlossaryChain:
         self.vector_store = load_vector_store()
         self.retriever = self.vector_store.as_retriever()
         self.llm = ChatMistralAI(
-            model="mistral-large-latest",
+            # model="mistral-large-latest", # "error","message":"Service tier capacity exceeded for this model.","type":"service_tier_capacity_exceeded
+            model="open-mistral-7b", # we must use the open-weight model
             mistral_api_key=MISTRAL_API_KEY,
             temperature=0.2
         )
@@ -38,16 +39,20 @@ class GlossaryChain:
 
     def invoke(self, input: str) -> str:
         return self.chain.invoke(input=input)
-        
+
 
 def format_docs(docs: list[Document]) -> str:
     """Format retrieved documents into a readable string"""
     return "\n\n".join(doc.page_content for doc in docs)
 
-@st.cache_data
+@st.cache_resource
 def load_vector_store() -> FAISS:
+    import os
+    # Get the absolute path to the faiss_index directory
+    current_dir = os.path.dirname(os.path.abspath(__file__))
+    faiss_path = os.path.join(os.path.dirname(current_dir), "faiss_index")
     return FAISS.load_local(
-        folder_path="faiss_index", 
+        folder_path=faiss_path, 
         embeddings = MistralAIEmbeddings(model="mistral-embed", mistral_api_key=MISTRAL_API_KEY),
         allow_dangerous_deserialization=True
     )