Class "kernel" "rbfkernel" "polykernel", "tanhkernel", "vanillakernel"

The built-in kernel classes in kernlab

Objects from the Class

Objects can be created by calls of the form new("rbfkernel"), new{"polykernel"}, new{"tanhkernel"}, new{"vanillakernel"}, new{"anovakernel"}, new{"besselkernel"}, new{"laplacekernel"}, new{"splinekernel"}, new{"stringkernel"}

or by calling the rbfdot, polydot, tanhdot, vanilladot, anovadot, besseldot, laplacedot, splinedot, stringdot functions etc..

Slots

.Data:

Object of class "function" containing the kernel function

kpar:

Object of class "list" containing the kernel parameters

Extends

Class "kernel", directly. Class "function", by class "kernel".

Methods

kernelMatrix

signature(kernel = "rbfkernel", x = "matrix"): computes the kernel matrix

kernelMult

signature(kernel = "rbfkernel", x = "matrix"): computes the quadratic kernel expression

kernelPol

signature(kernel = "rbfkernel", x = "matrix"): computes the kernel expansion

kernelFast

signature(kernel = "rbfkernel", x = "matrix"),,a: computes parts or the full kernel matrix, mainly used in kernel algorithms where columns of the kernel matrix are computed per invocation

Author

Alexandros Karatzoglou
alexandros.karatzoglou@ci.tuwien.ac.at

See also

dots

Examples

rbfkernel <- rbfdot(sigma = 0.1)
rbfkernel
#> new("rbfkernel", .Data = function (x, y = NULL) 
#> {
#>     if (!is(x, "vector")) 
#>         stop("x must be a vector")
#>     if (!is(y, "vector") && !is.null(y)) 
#>         stop("y must a vector")
#>     if (is(x, "vector") && is.null(y)) {
#>         return(1)
#>     }
#>     if (is(x, "vector") && is(y, "vector")) {
#>         if (!length(x) == length(y)) 
#>             stop("number of dimension must be the same on both data points")
#>         return(exp(sigma * (2 * crossprod(x, y) - crossprod(x) - 
#>             crossprod(y))))
#>     }
#> }, kpar = list(sigma = 0.1))
#> <bytecode: 0x564204d155f8>
#> <environment: 0x56420837f330>
#> attr(,"kpar")
#> attr(,"kpar")$sigma
#> [1] 0.1
#> 
#> attr(,"class")
#> [1] "rbfkernel"
#> attr(,"class")attr(,"package")
#> [1] "kernlab"
is(rbfkernel)
#> [1] "rbfkernel"        "kernel"           "function"         "OptionalFunction"
#> [5] "PossibleMethod"   "kfunction"       
kpar(rbfkernel)
#> $sigma
#> [1] 0.1
#>