ICGE (version 0.4.2)

proxi: Proximity Function

Description

Assume that n units are divided into k groups C1,...,Ck. The function calculates the proximity function from a specific unit x0 to the groups Cj.

Usage

proxi(d, dx0, pert = "onegroup")

Value

k-vector containing the proximity function value from x0 to each group.

Arguments

d

a distance matrix or a dist object with distance information between units.

dx0

an n-vector containing the distances from x0 to the other units.

pert

an n-vector that indicates which group each unit belongs to. Note that the expected values of pert are numbers greater than or equal to 1 (for instance 1,2,3,4..., k). The default value indicates there is only one group in data.

Author

Itziar Irigoien ; Konputazio Zientziak eta Adimen Artifiziala, Euskal Herriko Unibertsitatea (UPV/EHU), Donostia, Spain.

Conchita Arenas ; Departament d'Estadistica, Universitat de Barcelona, Barcelona, Spain.

References

Arenas, C. and Cuadras, C.M. (2002). Some recent statistical methods based on distances. Contributions to Science, 2, 183--191.

Cuadras, C.M., Fortiana, J. and Oliva, F. (1997). The proximity of an individual to a population with applications in discriminant analysis. Journal of Classification, 14, 117--136.

See Also

vgeo, deltas

Examples

data(iris)
d <- dist(iris[,1:4])

# xo contains a unit from one group, as for example group 1.
x0 <- c(5.3, 3.6, 1.1, 0.1) 
# distances between x0 and the other units.
dx0 <- rep(0,150)
for (i in 1:150){
	dif <-x0-iris[i,1:4]
	dx0[i] <- sqrt(sum(dif*dif))
}

proxi(d, dx0, iris[,5])


# xo contains a unit from one group, as for example group 2.
x0 <- c(6.4, 3.0, 4.8, 1.3) 
# distances between x0 and the other units.
dx0 <- rep(0,150)
for (i in 1:150){
	dif <-x0-iris[i,1:4]
	dx0[i] <- sqrt(sum(dif*dif))
}

proxi(d, dx0, iris[,5])