@smarshall Thanks for your message! I have a project that recently started that will take some of the first steps toward this capability, namely implementing adjoint-weighted tallies based on the previous work that was done by the group at MIT. I’m actually in the final stages of hiring a postdoc for this project and once that’s complete, the technical work will begin. Perhaps I can reach out to you directly at that point and we can discuss ways of collaborating on this?