x12 {ppclust}

Synthetic data set of two variables

Description

A synthetic data set described by Pal et al (2005). It consists of two continous variables forming two well-separated clusters in addition to two noise.

Usage

data(x12)

Format

A data frame with 12 rows and 2 numeric variables:

p1

a numeric variable ranging from -5.0 to 5.0

p2

a numeric variable ranging from -1.67 to 10.0

Note

The data set x12 is recommended to test the performances of the possibilistic and probabilistic clustering algorithms.

References

Pal, N. R., Pal, K. & Bezdek, J. C. (2005). A possibilistic fuzzy c-means clustering algorithm. IEEE Trans. Fuzzy Systems, 13 (4): 517-530. <doi:10.1109/TFUZZ.2004.840099>

Examples

data(x12)
# Descriptive statistics of the data set
summary(x12)
# Plot the data set
pairs(x12, pch=19, cex=2)