kmodes

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K-Modes Clustering

Perform k-modes clustering on categorical data.

Keywords
multivariate, cluster, category
Usage
kmodes(data, modes, iter.max = 10, weighted = FALSE)
Arguments
data
A matrix or data frame of categorical data. Objects have to be in rows, variables in columns.
modes
Either the number of modes or a set of initial (distinct) cluster modes. If a number, a random set of (distinct) rows in data is chosen as the initial modes.
iter.max
The maximum number of iterations allowed.
weighted
Whether usual simple-matching distance between objects is used, or a weighted version of this distance.
Details

The $k$-modes algorithm (Huang, 1997) an extension of the k-means algorithm by MacQueen (1967).

The data given by data is clustered by the $k$-modes method (Huang, 1997) which aims to partition the objects into $k$ groups such that the distance from objects to the assigned cluster modes is minimized. By default simple-matching distance is used to determine the dissimilarity of two objects. It is computed by counting the number of mismatches in all variables. Alternative this distance is weighted by the frequencies of the categories in data (see Huang, 1997, for details). If an initial matrix of modes is supplied, it is possible that no object will be closest to one or more modes. In this case less cluster than supplied modes will be returned and a warning is given.

Value

  • An object of class "kmodes" which is a list with components:
  • clusterA vector of integers indicating the cluster to which each object is allocated.
  • sizeThe number of objects in each cluster.
  • modesA matrix of cluster modes.
  • withindiffThe within-cluster simple-matching distance for each cluster.
  • iterationsThe number of iterations the algorithm has run.
  • weightedWhether weighted distances were used or not.

References

Huang, Z. (1997) A Fast Clustering Algorithm to Cluster Very Large Categorical Data Sets in Data Mining. in KDD: Techniques and Applications (H. Lu, H. Motoda and H. Luu, Eds.), pp. 21-34, World Scientific, Singapore.

MacQueen, J. (1967) Some methods for classification and analysis of multivariate observations. In Proceedings of the Fifth Berkeley Symposium on Mathematical Statistics and Probability, eds L. M. Le Cam & J. Neyman, 1, pp. 281-297. Berkeley, CA: University of California Press.

Aliases
  • kmodes
  • print.kmodes
Examples
### a 5-dimensional toy-example:

## generate data set with two groups of data:
set.seed(1)
x <- rbind(matrix(rbinom(250, 2, 0.25), ncol = 5),
           matrix(rbinom(250, 2, 0.75), ncol = 5))
colnames(x) <- c("a", "b", "c", "d", "e")

## run algorithm on x:
(cl <- kmodes(x, 2))

## and visualize with some jitter:
plot(jitter(x), col = cl$cluster)
points(cl$modes, col = 1:5, pch = 8)
Documentation reproduced from package klaR, version 0.6-11, License: GPL-2

Community examples

riteshtawde16@gmail.com at Sep 17, 2017 klaR v0.6-12

### a 5-dimensional toy-example: ## generate data set with two groups of data: set.seed(1) x <- rbind(matrix(rbinom(250, 2, 0.25), ncol = 5), matrix(rbinom(250, 2, 0.75), ncol = 5)) colnames(x) <- c("a", "b", "c", "d", "e") ## run algorithm on x: (cl <- kmodes(x, 2)) ## and visualize with some jitter: plot(jitter(x), col = cl$cluster) points(cl$modes, col = 1:5, pch = 8)