“…This means that the generated features from FDA are discriminative in nature. Kernel FDA, its nonlinear extension, is used extensively such as in [74,75,80,92,98,102,103,105,118,130,151,169,175,183,195,204,222,232,238,258,266,294]. One variant of FDA is exponential discriminant analysis (EDA) which solves the singularity problem in the FDA covariance matrices by taking their exponential forms [281,283].…”