Seminar • Algorithms and Complexity • Almost Linear Time Algorithms for Max-flow and More

Wednesday, March 23, 2022 1:00 pm - 1:00 pm EDT (GMT -04:00)

Please note: This seminar will be given online.

Sushant Sachdeva, Assistant Professor
Department of Computer Science, University of Toronto

We give the first almost-linear time algorithm for computing exact maximum flows and minimum-cost flows on directed graphs. By well known reductions, this implies almost-linear time algorithms for several problems including bipartite matching, optimal transport, and undirected vertex connectivity.

Our algorithm is designed using a new Interior Point Method (IPM) that builds the flow as a sequence of almost-linear number of approximate undirected minimum-ratio cycles, each of which is computed and processed very efficiently using a new dynamic data structure.

Our framework extends to give an almost-linear time algorithm for computing flows that minimize general edge-separable convex functions to high accuracy. This gives the first almost-linear time algorithm for several problems including entropy-regularized optimal transport,
matrix scaling, p-norm flows, and Isotonic regression.

Joint work with Li Chen, Rasmus Kyng, Yang Liu, Richard Peng, and Maximilian Probst Gutenberg.

Bio: Sushant Sachdeva is a faculty member at the CS dept. at the University of Toronto and a Vector Institute affiliate. He is interested in Algorithms, and its connections to optimization, machine learning, and statistics. His recent research focus has been the design of fast algorithms for graph problems.