RmixmodCombi (version 1.0)

combMat: Combining Matrix

Description

Create a combining matrix

Usage

combMat(K,l1,l2)

Arguments

K

The original number of classes: the matrix will define a combining from K to (K-1) classes.

l1

Label of one of the two classes to be combined.

l2

Label of the other class to be combined.

Value

If z is a vector (length K) whose kth entry is the probability that an observation belongs to the kth class in a K-class classification, then combiM %*% z is the vector (length K-1) whose kth entry is the probability that the observation belongs to the kth class in the K-1-class classification obtained by combining classes l1 and l2 in the initial classification.

References

J.-P. Baudry, A. E. Raftery, G. Celeux, K. Lo and R. Gottardo (2010). Combining mixture components for clustering. Journal of Computational and Graphical Statistics, 19(2):332-353.

See Also

mixmodCombi

Examples

set.seed(1)

data(Baudry_etal_2010_JCGS_examples)
res <- mixmodCombi(ex4.1, nbCluster = 1:8)

res@hierarchy[[5]]@proba # each line of this matrix is the vector of the posterior probabilities of
# each class for an observation in the 5-cluster solution

t(combMat(5, 3, 4) %*% t(res@hierarchy[[5]]@proba) ) # each line of this matrix is the vector of
# the posterior probabilities of each class for an observation in the 4-cluster solution obtained by
# combining clusters 3 and 4 in the 5-cluster solution