Tutte Colloquium - Dmitriy Drusvyatskiy

Friday, June 25, 2021 3:30 pm - 3:30 pm EDT (GMT -04:00)

Title: From low probability to high confidence in stochastic convex optimization

Speaker: Dmitriy Drusvyatskiy
Affliliation: University of Washington
Zoom: Contact Emma Watson


Standard results in stochastic convex optimization bound the number of samples that an algorithm needs to generate a point with small function value in expectation. More nuanced high probability guarantees are rare, and typically either rely on “light-tail” noise assumptions or exhibit worse sample complexity. In this work, we show that a wide class of stochastic optimization algorithms can be augmented with high confidence bounds at an overhead cost that is only logarithmic in the confidence level and polylogarithmic in the condition number. The procedure we propose, called proxBoost, is elementary and builds on two well-known ingredients: robust distance estimation and the proximal point method. We discuss consequences for both streaming (online) algorithms and offline algorithms based on empirical risk minimization.