On Fast Computation of Gradients for CANDECOMP/PARAFAC Algorithms
arXiv:1204.1586
Abstract
Product between mode- unfolding $\bY_{(n)}$ of an -D tensor $\tY$ and Khatri-Rao products of factor matrices $\bA^{(m)}$, exists in algorithms for CANDECOMP/PARAFAC (CP). If $\tY$ is an error tensor of a tensor approximation, this product is the gradient of a cost function with respect to factors, and has the largest workload in most CP algorithms. In this paper, a fast method to compute this product is proposed. Experimental verification shows that the fast CP gradient can accelerate the CP_ALS algorithm 2 times and 8 times faster for factorizations of 3-D and 4-D tensors, and the speed-up ratios can be 20-30 times for higher dimensional tensors.
12 pages, 2 figures