title: Factor analysis models via I-divergence optimization.
abstract: Given a positive definite covariance matrix [Formula: see text] of dimension n, we approximate it with a covariance of the form [Formula: see text], where H has a prescribed number [Formula: see text] of columns and [Formula: see text] is diagonal. The quality of the approximation is gauged by the I-divergence between the zero mean normal laws with covariances [Formula: see text] and [Formula: see text], respectively. To determine a pair (H, D) that minimizes the I-divergence we construct, by lifting the minimization into a larger space, an iterative alternating minimization algorithm (AML) à la Csiszár-Tusnády. As it turns out, the proper choice of the enlarged space is crucial for optimization. The convergence of the algorithm is studied, with special attention given to the case where D is singular. The theoretical properties of the AML are compared to those of the popular EM algorithm for exploratory factor analysis. Inspired by the ECME (a Newton-Raphson variation on EM), we develop a similar variant of AML, called ACML, and in a few numerical experiments, we compare the performances of the four algorithms.
authors.affiliation: IEIIT - CNR, Via Gradenigo, 6-a, 35129, Padua, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Finesso
authors.affiliation: Korteweg-de Vries Institute for Mathematics, Universiteit van Amsterdam, POBox 94248, 1090 GE , Amsterdam, The Netherlands. spreij@uva.nl.
authors.forename: Peter
authors.initials: P
authors.lastname: Spreij
mesh_terms: D000465:Algorithms; D005163:Factor Analysis, Statistical; D006801:Humans; D011594:Psychometrics; D013223:Statistics as Topic
keywords: I-divergence; alternating minimization; factor analysis; optimal approximate model