核函数

表达式

内核参数

径向基函数(RBF)

$K\left(x_i,x_j\right)=\exp \left(-\gamma \Vert x_i-x_j\Vert \ast \Vert x_i-x_j\Vert \right)$

$\gamma$

线性核函数(Linear)

$K\left(x_i,x_j\right)=x_i^{\text{T}}{x}_j$

-

多项式核函数(Polynomial)

$K\left(x_i,x_j\right)={\left(-\gamma x_i^{\text{T}}x+1\right)}^d$

$\gamma ,d$

逻辑回归(sigmoid)

$K\left(x_i,x_j\right)=\tanh {\left(-\gamma x_i^{\text{T}}x+1\right)}^d$

$\gamma$