TCS+ talk: Wednesday, April 26 — Santosh Vempala, Georgia Tech

by plustcs

The next TCS+ talk will take place next Wednesday, April 26th at 1:00 PM Eastern Time (10:00 AM Pacific Time, 19:00 Central European Time, 17:00 UTC). Santosh Vempala (Georgia Tech) will present joint work with Yin Tat Lee to appear in STOC’17, “Sampling Polytopes: From Euclid to Riemann”  (abstract below).

Please make sure you reserve a spot for your group to join us live by signing up on the online form. As usual, for more information about the TCS+ online seminar series and the upcoming talks, or to suggest a possible topic or speaker, please see the website.

We introduce the Geodesic Walk for sampling Riemannian manifolds and apply it to the problem of generating uniform random points from the interior of a convex polytope in n-dimensional Euclidean space. The walk is a simulation of a stochastic differential equation defined using a convex barrier function; each step is the solution of an ordinary differential equation. It improves the time complexity of sampling polytopes and is the first walk to achieve sub-quadratic complexity. Most of the talk will be spent introducing relevant aspects of manifolds, stochastic processes, efficient solution of differential equations, and how this walk overcomes the bottlenecks of random walks in Euclidean space. No background in string theory (or Riemannian geometry) will be assumed.

Joint work with Lee Yin Tat.