fclust (version 2.1.1.1)

PC: Partition coefficient

Description

Produces the partition coefficient index. The optimal number of clusters k is is such that the index takes the maximum value.

Usage

PC (U)

Value

pc

Value of the partition coefficient index

Arguments

U

Membership degree matrix

Author

Paolo Giordani, Maria Brigida Ferraro, Alessio Serafini

References

Bezdek J.C., 1974. Cluster validity with fuzzy sets. Journal of Cybernetics, 3, 58-73.

See Also

PE, MPC, SIL, SIL.F, XB, Fclust, Mc

Examples

## McDonald's data
data(Mc)
names(Mc)
## data normalization by dividing the nutrition facts by the Serving Size (column 1)
for (j in 2:(ncol(Mc)-1))
Mc[,j]=Mc[,j]/Mc[,1]
## removing the column Serving Size
Mc=Mc[,-1]
## fuzzy k-means
## (excluded the factor column Type (last column))
clust=FKM(Mc[,1:(ncol(Mc)-1)],k=6,m=1.5,stand=1)
## partition coefficient
pc=PC(clust$U)