Low-Rank Tensor Approximation of Weights in Large Language Models via Cosine Lanczos Bidiagonalization

Abstract

Large Language Models (LLMs) have demonstrated remarkable capabilities across diverse natural language tasks but suffer from extremely large memory footprints and computational costs. In this paper, we introduce a tensor compression framework based on the cproduct for computing low rank approximation In the first part of our approach, we leverage the algebraic structure of the cproduct to represent weight tensors such as those in embedding layers, attention projections, and feed forward networks in a transform domain where frontal slices can be jointly approximated by low rank tensor factors. This enables computationally efficient compression that exploits multidimensional correlations beyond traditional SVD methods.