Table 2.

SVM Kernel Formulas.

Kernel	$\mathbf{K}\left({\mathit{x}}_{\mathit{i}}, {\mathit{x}}_{\mathit{j}}\right)$
Linear	$X_i^T, X_j$
Polynominal	${\left(\gamma X_i^T{X}_j+r\right)}^d,\gamma >0$
Radial Basis Function (RBF)	exp$\left(-\gamma \Vert X_i-X_j\Vert {}^2\right),\gamma >0$
Sigmoid	$\tanh \left(\gamma X_i^T{X}_j+r\right)$