Higher order multi-dimension reduction methods via Einstein product
Alaeddine Zahir, Khalide Jbilou, Ahmed Ratnani
TL;DR
This work advances dimensionality reduction by extending graph-based matrix methods to multi-dimensional data through the Einstein product, preserving tensor structure and avoiding vectorization. It develops tensor-valued generalizations of PCA, LPP, ONPP, OLPP, NPP, Laplacian Eigenmaps, and LLE, along with kernelized and supervised variants, including multi-weight and repulsion enhancements. The framework yields corresponding eigen-tensor or left-singular-tensor solutions and provides out-of-sample extensions for practical use. Experimental results on MNIST and GTDB demonstrate competitive performance and highlight the benefits of maintaining multi-dimensional structure for color images and high-dimensional data.
Abstract
This paper explores the extension of dimension reduction (DR) techniques to the multi-dimension case by using the Einstein product. Our focus lies on graph-based methods, encompassing both linear and nonlinear approaches, within both supervised and unsupervised learning paradigms. Additionally, we investigate variants such as repulsion graphs and kernel methods for linear approaches. Furthermore, we present two generalizations for each method, based on single or multiple weights. We demonstrate the straightforward nature of these generalizations and provide theoretical insights. Numerical experiments are conducted, and results are compared with original methods, highlighting the efficiency of our proposed methods, particularly in handling high-dimensional data such as color images.
