CIS 5590: Large-Scale Matrix Decomposition Tensors and Applications Instructor: Kai Zhang CIS @ Temple University, Spring 2018
What is a Tensor? A tensor is a multi-way extension of a matrix A multi-dimensional array A multi-linear map Examples Scalar, Vector, Matrices color images, videos data matrices, recorded at different times t ECG: electrode x ECG beat x time action recognition
Epilespy Sedure Detection
Fibers and Slices Third First Second
Tensor Matrication Definition: unfolds an N-way tensor into a matrix Mode-n matricization arranges the mode-n fibers as columns of a matrix Denoted X(n) As many rows as is the dimensionality of the nth mode As many columns as is the product of the dimensions of other modes
Tensor Multiplication Definition
Pictorial view of Tensor Multiplication
Mode-n Product Example
Kronecker Product
Khatri–Rao Matrix Product
Khatri–Rao Matrix Product
Tensor Decomposition CP decomposition
Tensor Decomposition Using matricization, we can re-write the CP decomposition ALS Algorithm
Tucker Decomposition
ALS Solution for Turker
Tucker Decomposition