Conversation Knowledge Graph
This type of memory uses a knowledge graph to recreate memory.
Using memory with LLM
from langchain.llms import OpenAI
from langchain.memory import ConversationKGMemory
llm = OpenAI(temperature=0)
memory = ConversationKGMemory(llm=llm)
memory.save_context({"input": "say hi to sam"}, {"output": "who is sam"})
memory.save_context({"input": "sam is a friend"}, {"output": "okay"})
memory.load_memory_variables({"input": "who is sam"})
    {'history': 'On Sam: Sam is friend.'}
We can also get the history as a list of messages (this is useful if you are using this with a chat model).
memory = ConversationKGMemory(llm=llm, return_messages=True)
memory.save_context({"input": "say hi to sam"}, {"output": "who is sam"})
memory.save_context({"input": "sam is a friend"}, {"output": "okay"})
memory.load_memory_variables({"input": "who is sam"})
    {'history': [SystemMessage(content='On Sam: Sam is friend.', additional_kwargs={})]}
We can also more modularly get current entities from a new message (will use previous messages as context).
memory.get_current_entities("what's Sams favorite color?")
    ['Sam']
We can also more modularly get knowledge triplets from a new message (will use previous messages as context).
memory.get_knowledge_triplets("her favorite color is red")
    [KnowledgeTriple(subject='Sam', predicate='favorite color', object_='red')]
Using in a chain
Let's now use this in a chain!
llm = OpenAI(temperature=0)
from langchain.chains import ConversationChain
from langchain.prompts.prompt import PromptTemplate
template = """The following is a friendly conversation between a human and an AI. The AI is talkative and provides lots of specific details from its context. 
If the AI does not know the answer to a question, it truthfully says it does not know. The AI ONLY uses information contained in the "Relevant Information" section and does not hallucinate.
Relevant Information:
{history}
Conversation:
Human: {input}
AI:"""
prompt = PromptTemplate(input_variables=["history", "input"], template=template)
conversation_with_kg = ConversationChain(
    llm=llm, verbose=True, prompt=prompt, memory=ConversationKGMemory(llm=llm)
)
conversation_with_kg.predict(input="Hi, what's up?")
    
    
    > Entering new ConversationChain chain...
    Prompt after formatting:
    The following is a friendly conversation between a human and an AI. The AI is talkative and provides lots of specific details from its context. 
    If the AI does not know the answer to a question, it truthfully says it does not know. The AI ONLY uses information contained in the "Relevant Information" section and does not hallucinate.
    
    Relevant Information:
    
    
    
    Conversation:
    Human: Hi, what's up?
    AI:
    
    > Finished chain.
    " Hi there! I'm doing great. I'm currently in the process of learning about the world around me. I'm learning about different cultures, languages, and customs. It's really fascinating! How about you?"
conversation_with_kg.predict(
    input="My name is James and I'm helping Will. He's an engineer."
)
    
    
    > Entering new ConversationChain chain...
    Prompt after formatting:
    The following is a friendly conversation between a human and an AI. The AI is talkative and provides lots of specific details from its context. 
    If the AI does not know the answer to a question, it truthfully says it does not know. The AI ONLY uses information contained in the "Relevant Information" section and does not hallucinate.
    
    Relevant Information:
    
    
    
    Conversation:
    Human: My name is James and I'm helping Will. He's an engineer.
    AI:
    
    > Finished chain.
    " Hi James, it's nice to meet you. I'm an AI and I understand you're helping Will, the engineer. What kind of engineering does he do?"
conversation_with_kg.predict(input="What do you know about Will?")
    
    
    > Entering new ConversationChain chain...
    Prompt after formatting:
    The following is a friendly conversation between a human and an AI. The AI is talkative and provides lots of specific details from its context. 
    If the AI does not know the answer to a question, it truthfully says it does not know. The AI ONLY uses information contained in the "Relevant Information" section and does not hallucinate.
    
    Relevant Information:
    
    On Will: Will is an engineer.
    
    Conversation:
    Human: What do you know about Will?
    AI:
    
    > Finished chain.
    ' Will is an engineer.'