Distance.R

#Distance measure for two vector(x,y)

#-------------------------------------------------------------------#
#Euclidean Distance
#-------------------------------------------------------------------#

euclidean <- function(x,y){ 
  sqrt(sum((x-y)^2,na.rm = TRUE))
}

#-------------------------------------------------------------------#
#Manhattan Distance
#-------------------------------------------------------------------#

manhattan <- function(x){ 
  sum(abs(x1 - x2),na.rm = TRUE)
}

#-------------------------------------------------------------------#
#Chebychev Distance 
#-------------------------------------------------------------------#

chebychev <- function(x,y){ 
  sum(max(abs(x - y),na.rm = TRUE))
}
#-------------------------------------------------------------------#
#Canberra Distance 
#-------------------------------------------------------------------#

canberra <- function(x,y){ 
  sum(abs(x - y)/(abs(x) + abs(y)),na.rm = TRUE)
}

#-------------------------------------------------------------------#
#Hamming Distance
#-------------------------------------------------------------------#

hamming <- function(x,y){
  length(which(x != y))/length(x)
}

#-------------------------------------------------------------------#
#Braycurtis Distance 
#-------------------------------------------------------------------#

braycurtis <- function(x,y){
  index <- c(which(is.na(x)),which(is.na(y)))
  x <- x[-index]
  y <- y[-index]
  sum(abs(x - y))/(sum(abs(x)) + sum(abs(y)))
}

#-------------------------------------------------------------------#
#Minkowki Distance
#p = 1 ~ manhattan 
#p = 2 ~ euclidean 
#-------------------------------------------------------------------#

minkowski <- function(x,y,p){ 
  sum(abs(x - y)^p,na.rm = TRUE)^(1/p)
}

#-------------------------------------------------------------------#
#Weighted Minkowski Distance
#-------------------------------------------------------------------#

wminkowski <- function(x,y,p,w){
  sum((w * abs(x - y)^p),na.rm = TRUE)^(1/p)
}


#-------------------------------------------------------------------#
#Cosine Distance
#-------------------------------------------------------------------#

cosine <- function(x,y){
  index <- c(which(is.na(x)),which(is.na(y)))
  x <- x[-index]
  y <- y[-index]
  1- (sum(x1*x2))/(sqrt(sum(x1^2))*sqrt(sum(x2^2)))
}

#-------------------------------------------------------------------#
#Mean square error
#-------------------------------------------------------------------#

meansqerror <- function(x,y){ 
  sum((x - y)^2,na.rm = TRUE)/length(which(!is.na(x) & !is.na(y)))
}

#-------------------------------------------------------------------#
#Mean absolute error
#-------------------------------------------------------------------#

meanabserror <- function(x,y){ 
  sum(abs(x - y),na.rm = TRUE)/length(which(!is.na(x) & !is.na(y)))
}