[Feature Request]: Support for different retrieval algorithms for RAG agents

[Smfakhoury]

Is your feature request related to a problem? Please describe.

Would be great to have the option to specify different retrieval algorithms/parameters for RAG agents.

Describe the solution you'd like

Perhaps as part of retrieve_config:

• Allow users to specify different retrieval algorithms: e.g. MMR or thresholds for similarity scores
• Time-weighted vector store retrieval
• Something like LangChain's MultiQuery retrieval (https://python.langchain.com/docs/modules/data_connection/retrievers/MultiQueryRetriever)
• etc.

Additional context

The main docs for RAG (https://microsoft.github.io/autogen/blog/2023/10/18/RetrieveChat) could have an additional section on customizing retrieval functions. Apologies if this feature already exists somewhere!

[rickyloynd-microsoft]

@thinkall

[thinkall]

Added to my TODO list. Thanks.