Joint Prompt Optimization of Stacked LLMs using Variational Inference - Sordoni, Alessandro; Yuan, Eric; Côté, Marc-Alexandre; Pereira, Matheus; Trischler, Adam; Xiao, Ziang; Hosseini, Arian; Niedtner, Friederike; Le Roux, Nicolas (Advances in Neural Information Processing Systems, 2023)