Update app.py

app.py

@@ -23,7 +23,8 @@ from langchain.text_splitter import CharacterTextSplitter
 from langchain.embeddings import OpenAIEmbeddings, HuggingFaceInstructEmbeddings
 from langchain.vectorstores import FAISS # FAISS instead of PineCone
 # from langchain.llms import OpenAI
-from langchain.chat_models import ChatOpenAI
+from langchain.llms import HuggingFaceHub
+#from langchain.chat_models import ChatOpenAI
 from langchain.memory import ConversationBufferMemory
 from langchain.chains import ConversationalRetrievalChain
 from htmlTemplates import css, bot_template, user_template 
@@ -54,7 +55,8 @@ def get_vectorstore(text_chunks):
 
 def get_conversation_chain(vectorstore):
     #llm = OpenAI()
-    llm = ChatOpenAI()
+    #llm = ChatOpenAI()
+    llm = HuggingFaceHub(repo_id="google/flan-t5-xxl", model_kwargs={"temperature":0.5, "max_length":512})
     memory = ConversationBufferMemory(memory_key='chat_history', return_messages=True)
     conversation_chain = ConversationalRetrievalChain.from_llm(
         llm=llm,