PC {fclust}

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)

Arguments

U

Membership degree matrix

Value

pc

Value of the partition coefficient index

Author(s)

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)