Master's Thesis Defence | Sammy Shi, On initializations of NMF

Wednesday, May 13, 2026 1:00 pm - 2:00 pm EDT (GMT -04:00)

Location

MC 6460

Candidate 

Sammy Shi | Applied Mathematics, University of Waterloo

Title

On initializations of NMF

Abstract

Recent literatures established provable guarantees for sketching-based initialization in unconstrained two-block matrix factorization. This talk explores the theoretical limits and numerical implications of adapting these frameworks to Non-negative Matrix Factorization (NMF).

After quickly reviewing NMF fundamentals, randomized numerical linear algebra (sketching), and spectral initialization frameworks, we will detail our progress in generalizing unconstrained proof frameworks to the NMF setting. Time permitting, we will also discuss why achieving a "good" NMF initialization under proximal methods remains inherently difficult, through the lens of (active) manifold identification. Finally, numerical results and experiments will be addressed.