Amazon Scientist Hamed Karimi Wins 2026 ECML PKDD Test-of-Time Award

Amazon senior applied scientist Hamed Karimi and coauthors Julie Nutini and Mark Schmidt received the 2026 ECML PKDD Test-of-Time Award for their 2016 paper on linear convergence of gradient and proximal-gradient methods under the Polyak–Łojasiewicz condition. The paper showed that this 1963 inequality guarantees linear convergence even when models lack a single best solution, unifying scattered optimization results and extending them to nonsmooth landscapes and algorithms such as coordinate, sign, and stochastic gradient descent. It has been cited over 2,000 times and appears in graduate textbooks.