“…Typical examples of such classification methods are clustering techniques, such as Ward's method, K-means clustering, and principal component analysis (PCA; e.g., Key and Crane, 1986;Cheng and Wallace, 1993;Hoffmann andSchkunzen, 2013, Kato et al, 2013;Miyasaka et al, 2020). Machine learning methods, including self-organizing maps (e.g., Hewiston and Crane, 2002;Cassano et al, 2006;Johnson et al, 2008;Ohba et al, 2016;Tamaki et al, 2018) and support vector machines (e.g., Kimura et al, 2009;Ortiz-García et al, 2014;Su et al, 2018), are now being used for classification or selection problems.…”