Multiple discriminant analysis
Multiple Discriminant Analysis (MDA) is a method for compressing a multivariate signal to yield a lower-dimensional signal amenable to classification.
MDA is not directly used to perform classification. It merely supports classification by yielding a compressed signal amenable to classification. The method described in Duda et al. (2001) §3.8.3 projects the multivariate signal down to an M−1 dimensional space where M is the number of categories.