@ARTICLE\{IMM2009-05806, author = "M. M{\o}rup and L. K. Hansen", title = "Automatic Relevance Determination for Multiway Models", year = "2009", pages = "352 - 363", journal = "Journal of Chemometrics, Special Issue: In Honor of Professor Richard A. Harshman", volume = "23", editor = "", number = "7-8", publisher = "John Wiley \& Sons, Ltd", url = "http://www2.compute.dtu.dk/pubdb/pubs/5806-full.html", abstract = "Estimating the adequate number of components is an important yet difficult problem in multi-way modelling. We demonstrate how a Bayesian framework for model selection based on Automatic Relevance Determination (ARD) can be adapted to the Tucker and {CP} models. By assigning priors for the model parameters and learning the hyperparameters of these priors the method is able to turn off excess components and simplify the core structure at a computational cost of fitting the conventional Tucker/{CP} model. To investigate the impact of the choice of priors we based the {ARD} on both Laplace and Gaussian priors corresponding to regularization by the sparsity promoting l1-norm and the conventional l2-norm, respectively. While the form of the priors had limited effect on the results obtained the {ARD} approach turned out to form a useful, simple, and efficient tool for selecting the adequate number of components of data within the Tucker and {CP} structure. For the Tucker and {CP} model the approach performs better than heuristics such as the Bayesian Information Criterion, Akaikes Information Criterion, {DIFFIT} and the numerical convex hull (NumConvHull) while operating only at the cost of estimating an ordinary {CP}/Tucker model. For the {CP} model the {ARD} approach performs almost as well as the core consistency diagnostic. Thus, the {ARD} framework is a simple yet efficient tool for the estimation of the adequate number of components in multi-way models. A Matlab implementation of the proposed algorithm is available for download at www.erpwavelab.org." }