R/kerFctn.R

In functionaldata/tFrechet: Statistical Analysis for Random Objects and Non-Euclidean Data

kerFctn <- function(kernel_type){
  if (kernel_type=='gauss'){
    ker <- function(x){
      dnorm(x) #exp(-x^2 / 2) / sqrt(2*pi)
    }
  } else if(kernel_type=='rect'){
    ker <- function(x){
      as.numeric((x<=1) & (x>=-1))
    }
  } else if(kernel_type=='epan'){
    ker <- function(x){
      n <- 1
      (2*n+1) / (4*n) * (1-x^(2*n)) * (abs(x)<=1)
    }
  } else if(kernel_type=='gausvar'){
    ker <- function(x) {
      dnorm(x)*(1.25-0.25*x^2)
    }
  } else if(kernel_type=='quar'){
    ker <- function(x) {
      (15/16)*(1-x^2)^2 * (abs(x)<=1)
    }
  } else {
    stop('Unavailable kernel')
  }
  return(ker)
}