dist.std.data {nnspat}

Interpoint Distance Matrix for Standardized Data

Description

This function computes and returns the distance matrix computed by using the specified distance measure to compute the distances between the rows of a data matrix which is standardized row or column-wise. That is, the output is the interpoint distance (IPD) matrix of the rows of the given set of points x dist function in the stats package of the standard R distribution. The argument column is the logical argument (default=TRUE) to determine row-wise or column-wise standardization. If TRUE each column is divided by its standard deviation, else each row is divided by its standard deviation. This function is different from the dist function in the stats package. dist returns the distance matrix in a lower triangular form, and dist.std.data returns in a full matrix of distances of standardized data set. ... are for further arguments, such as method and p, passed to the dist function.

Usage

dist.std.data(x, column = TRUE, ...)

Arguments

x

A set of points in matrix or data frame form where points correspond to the rows.

column

A logical argument (default is TRUE) to determine whether standardization is row-wise or column-wise. If TRUE it is column-wise else row-wise standardization.

...

Additional parameters to be passed on the dist function.

Value

A distance matrix whose i,j-th entry is the distance between rows i and j of x, which is standardized row-wise or column-wise.

Author(s)

Elvan Ceyhan

See Also

dist, ipd.mat, and ipd.mat.euc

Examples

n<-20  #or try sample(1:20,1)
Y<-matrix(runif(3*n),ncol=3)
ipd<-ipd.mat(Y)
range(ipd)

ipd2<-dist.std.data(Y) #distance of standardized data
range(ipd2)

ipd2<-dist.std.data(Y,method="max") #distance of standardized data
range(ipd2)

#############
Y<-matrix(runif(60,0,100),ncol=3)
ipd<-ipd.mat(Y)
range(ipd)

ipd2<-dist.std.data(Y) #distance of standardized data
range(ipd2)