Figure 5
From: Kernelized partial least squares for feature reduction and classification of gene microarray data
Polynomial Kernel. The outputs of the polynomial kernel as functions of the cosine of the angles between vectors. Three functions are depicted in dashed-double-dotted-blue, dashed-single-dotted-red, dotted-green, and dashed-purple curves, corresponding to the cases where the polynomial degree is 1, 2, 3, and 4 respectively.