nnspat (version 0.1.2)

seg.ind: Dixon's Segregation Indices for NNCTs

Description

Returns Dixon's segregation indices in matrix form based on entries of the NNCT, ct. Segregation index for cell \(i,j\) is defined as \(log(N_{ii}(n-n_i)/((n_i-N_{ii})(n_i-1))\) if \(i=j\) and as \(log(N_{ij}(n-n_j-1)/((n_i-N_{ij})(n_j))\) if \(i \ne j\). See (dixon:NNCTEco2002,ceyhan:SiM-seg-ind2014;textualnnspat).

The argument inf.corr is a logical argument (default=FALSE) to avoid \(\pm \infty\) for the segregation indices. If TRUE indices are modified so that they are finite and if FALSE the above definition is used. (See ceyhan:SiM-seg-ind2014;textualnnspat for more detail).

Usage

seg.ind(ct, inf.corr = FALSE)

Value

Returns a matrix of segregation indices which is of the same dimension as ct.

Arguments

ct

A contingency table, in particular an NNCT

inf.corr

A logical argument (default=FALSE). If TRUE, indices are modified so that they are finite and if FALSE the above definition in the description is used.

Author

Elvan Ceyhan

See Also

Pseg.coeff, seg.coeff, Zseg.ind, and Zseg.ind.ct

Examples

n<-20  #or try sample(1:20,1)
Y<-matrix(runif(3*n),ncol=3)
ipd<-ipd.mat(Y)
cls<-sample(1:2,n,replace = TRUE)  #or try cls<-rep(1:2,c(10,10))
ct<-nnct(ipd,cls)
ct
seg.ind(ct)
seg.ind(ct,inf.corr = TRUE)

#cls as a factor
na<-floor(n/2); nb<-n-na
fcls<-rep(c("a","b"),c(na,nb))
ct<-nnct(ipd,fcls)

seg.ind(ct)

#############
n<-40
Y<-matrix(runif(3*n),ncol=3)
ipd<-ipd.mat(Y)
cls<-sample(1:4,n,replace = TRUE)  #or try cls<-rep(1:2,c(10,10))
ct<-nnct(ipd,cls)

seg.ind(ct)
seg.ind(ct,inf.corr = TRUE)

ct<-matrix(c(0,10,5,5),ncol=2)
seg.ind(ct)

seg.ind(ct,inf.corr = TRUE)