7.7 Dimension Reduction Method
7.7.2 Discriminant Analysis (LDA)
LDA, QDA, ODA (Oriented Discriminant Analysis) https://kilthub.cmu.edu/articles/journal_contribution/Oriented_Discriminant_Analysis_ODA_/6557243?file=12039518
Partial Least Squares Discriminant Analysis (PLS-DA)
also can do classification
7.7.4 Principal Component Analysis (PCA)
https://www.r-bloggers.com/2022/11/pca-for-categorical-variables-in-r/
https://en.wikipedia.org/wiki/Kosambi%E2%80%93Karhunen%E2%80%93Lo%C3%A8ve_theorem
kernel PCA
Multilinear Principal Component Analysis,MPCA https://en.wikipedia.org/wiki/Multilinear_principal_component_analysis