Computational/Statistical Gaps for Learning Neural Networks

Published on ● Video Link: https://www.youtube.com/watch?v=CRoT6gEzSSU



Duration: 59:05
476 views
11


Adam Klivans (University of Texas, Austin)
Probability, Geometry, and Computation in High Dimensions
Seminar, Dec. 1, 2020

It has been known for decades that a polynomial-size training sample suffices for learning neural networks. Most theoretical results, however, indicate that these learning tasks are computationally intractable. Where exactly is the dividing line? In this talk we consider arguably the most well-studied scenario, namely when the marginal distribution on inputs is Gaussian, and show unconditionally that gradient descent cannot learn even one-layer neural networks. We then point to a potential way forward and sketch the first fixed-parameter tractable algorithm for learning deep ReLU networks. Its running time is polynomial in the ambient dimension and exponential in only the network's parameters. This is the first nontrivial positive result for networks of depth more than two.

https://simons.berkeley.edu/events/computationalstatistical-gaps-learning-neural-networks




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Tags:
Simons Institute
theoretical computer science
UC Berkeley
Computer Science
Theory of Computation
Theory of Computing