RBF {kerntools} | R Documentation |
Gaussian RBF (Radial Basis Function) kernel
Description
'RBF()' computes the RBF kernel between all possible pairs of rows of a matrix or data.frame with dimension NxD.
Usage
RBF(X, g = NULL)
Arguments
X |
Matrix or data.frame that contains real numbers ("integer", "float" or "double"). |
g |
Gamma hyperparameter. If g=0 or NULL, 'RBF()' returns the matrix of squared Euclidean distances instead of the RBF kernel matrix. |
Details
Let x_i,x_j
be two real vectors. Then, the RBF kernel is defined as:
K_{RBF}(x_i,x_j)=\exp(-\gamma \|x_i - x_j \|^2)
Sometimes the RBF kernel is given a hyperparameter called sigma. In that case:
\gamma = 1/\sigma^2
.
Value
Kernel matrix (dimension: NxN).
Examples
dat <- matrix(rnorm(250),ncol=50,nrow=5)
RBF(dat,g=0.1)
[Package kerntools version 1.0.2 Index]