lastk {inaparc}

Initialization of cluster prototypes using the last k objects

Description

Initializes the cluster prototypes matrix using the last k objects at the bottom of data set.

Usage

lastk(x, k)

Arguments

x

a numeric vector, data frame or matrix.

k

an integer specifying the number of clusters.

Details

The function lastk simply uses the last k objects as the protoypes of clusters. If the data is already sorted in any order it may result with no good initial prototypes because the objects be close to each other in a sorted matrix. Therefore, shuffling of the data set as a pre-processing step may improve the quality with this prototyping technique.

Value

an object of class ‘inaparc’, which is a list consists of the following items:

v

a numeric matrix containing the initial cluster prototypes.

ctype

a string representing the type of centroid, which used to build prototype matrix. Its value is ‘obj’ with this function because the cluster prototype matrix contains the objects.

call

a string containing the matched function call that generates this ‘inaparc’ object.

Author(s)

Zeynel Cebeci, Cagatay Cebeci

See Also

aldaoud, ballhall, crsamp, firstk, forgy, hartiganwong, inofrep, inscsf, insdev, kkz, kmpp, ksegments, ksteps, lhsmaximin, lhsrandom, maximin, mscseek, rsamp, rsegment, scseek, scseek2, spaeth, ssamp, topbottom, uniquek, ursamp

Examples

data(iris)
res <- lastk(x=iris[,1:4], k=5)
v <- res$v
print(v)