“…To improve efficiency, various numerical techniques have been tested, such as ridge regression (Rayens & Mitchell, 1997), line search (Bro, 1998;Tomasi, 2006;Rajih et al, 2008), and gradient-based methods (Franc, 1992;Paatero, 1999;Tomasi, 2006). Although performance of an algorithm depends on the data and the fit model, the ALS algorithm in Appendix A seems to provide the most accurate Parafac solution at the cost of slow convergence (see Faber et al, 2003;Tomasi & Bro, 2006). Andersson and Bro (2000) provide an excellent open-source MATLAB toolbox with techniques for fitting various multimode component models, including the ALS algorithm for fitting the Parafac model.…”