Fig. 4: PCA analysis of the proposed optical kernel.
From: Electromagnetic wave-based extreme deep learning with nonlinear time-Floquet entanglement

a, b Two different perspectives of Projected data for three different cases: (i) linear case, (ii) square-law nonlinearity (x2), and (iii) the proposed nonlinearity. c–e sinc(ζin) interpolation results for three aforementioned cases, respectively.