Thu, 19 Jan 2023

14:00 - 15:00
L3

Bridging the divide: from matrix to tensor algebra for optimal approximation and compression

Misha Kilmer
(Tufts University)
Abstract

Tensors, also known as multiway arrays, have become ubiquitous as representations for operators or as convenient schemes for storing data. Yet, when it comes to compressing these objects or analyzing the data stored in them, the tendency is to ``flatten” or ``matricize” the data and employ traditional linear algebraic tools, ignoring higher dimensional correlations/structure that could have been exploited. Impediments to the development of equivalent tensor-based approaches stem from the fact that familiar concepts, such as rank and orthogonal decomposition, have no straightforward analogues and/or lead to intractable computational problems for tensors of order three and higher.

In this talk, we will review some of the common tensor decompositions and discuss their theoretical and practical limitations. We then discuss a family of tensor algebras based on a new definition of tensor-tensor products. Unlike other tensor approaches, the framework we derive based around this tensor-tensor product allows us to generalize in a very elegant way all classical algorithms from linear algebra. Furthermore, under our framework, tensors can be decomposed in a natural (e.g. ‘matrix-mimetic’) way with provable approximation properties and with provable benefits over traditional matrix approximation. In addition to several examples from recent literature illustrating the advantages of our tensor-tensor product framework in practice, we highlight interesting open questions and directions for future research.

A scalable and robust vertex-star relaxation for high-order FEM
Brubeck Martinez, P Farrell, P SIAM Journal on Scientific Computing volume 44 issue 5 A2991-A3017 (20 Sep 2022)
Image of sculpture

On June 27th, in the Reception area of the Mathematical Institute, Oxford artist Andy Bullock unveiled his most ambitious knot sculpture to date, a large floor-based work titled ‘All we ever wanted was everything / 24.02.22 (for Ukraine)’ constructed using 70 metres of metal trunking. As with all his knot sculptures they often reference issues of complexity with situations and people, the personal and interpersonal; focusing on what it means to be human.

Reliable and efficient parameter estimation using approximate continuum limit descriptions of stochastic models
Simpson, M Baker, R Buenzli, P Nicholson, R Maclaren, O Journal of Theoretical Biology volume 549 (22 Jun 2022)
Efficient Bayesian inference for mechanistic modelling with high-throughput data.
Martina Perez, S Sailem, H Baker, R PLoS computational biology volume 18 issue 6 e1010191-e1010191 (21 Jun 2022)
Scalable subspace methods for derivative-free nonlinear least-squares optimization
Cartis, C Roberts, L MATHEMATICAL PROGRAMMING (09 Jun 2022)
The Riemann Zeros and Eigenvalue Asymptotics
Berry, M Keating, J A Half-century of Physical Asymptotics and Other Diversions: Selected Works By Michael Berry 349-380 (01 Jan 2017)
A new asymptotic representation for ζ(12+it)and quantum spectral determinants
Berry, M Keating, J A Half-century of Physical Asymptotics and Other Diversions: Selected Works By Michael Berry 456-478 (01 Jan 2017)
Controlling Swarms toward Flocks and Mills
Carrillo, J Kalise, D Rossi, F Trélat, E SIAM Journal on Control and Optimization volume 60 issue 3 1863-1891 (21 Jun 2022)
Universality in anisotropic linear anelasticity
Goriely, A Journal of Elasticity volume 150 241-259 (13 Jul 2022)
Subscribe to