Comments on a recently published paper ‘some surprising properties of multivariate curve resolution-alternating least squares (MCR-ALS) algorithms’

Abstract

Some of the results given in a recently published paper in this journal concerning some surprising properties of the multivariate curve resolution-alternating least squares (MCR-ALS) method are discussed. My results showed that the surprising properties of MCR-ALS refer only to the slow linear convergence properties of ALS algorithms and to rounding error computer calculations. Results obtained by MCR-ALS for the first data example were correct and no significant differences were observed in the resolved profiles. In the second more complex data example, large rotation ambiguities were present for the spectrum profile of the very minor second component which was not correctly estimated by MCR-ALS. However, even in this case, the subspaces spanned by the MCR-ALS solutions were also very close to the correct ones apart from slow convergence properties of the MCR-ALS algorithm in this case. Copyright © 2009 John Wiley & Son.