Figure 4
From: Kernelized partial least squares for feature reduction and classification of gene microarray data
Dot product kernel. The outputs of dot product kernel as functions of the angles between vectors. Four functions are depicted in solid-blue, long-dashed-red, short-dashed-green and dotted-purple curves, corresponding to the cases where the product of the norms of the and vectors is equal to 0.5, 1, 2 and 3 respectively.