clusterGGM (version 0.1.1)

min_clusters: Calculate the Minimum Number of Clusters

Description

Compute the minimum number of clusters achievable by the clusterpath penalty using the provided weight matrix.

Usage

min_clusters(W)

Value

An integer giving the minimum number of clusters.

Arguments

W

The weight matrix for the clusterpath penalty.

Author

Daniel J.W. Touw

References

D.J.W. Touw, A. Alfons, P.J.F. Groenen and I. Wilms (2025) Clusterpath Gaussian Graphical Modeling. arXiv:2407.00644. doi:10.48550/arXiv.2407.00644.

See Also

clusterpath_weights(), cggm(), cggm_cv()

Examples

# Generate data
set.seed(3)
Theta <- matrix(
  c(2, 1, 0, 0,
    1, 2, 0, 0,
    0, 0, 4, 1,
    0, 0, 1, 4),
  nrow = 4
)
X <- mvtnorm::rmvnorm(n = 100, sigma = solve(Theta))

# Estimate the covariance matrix
S <- cov(X)


# Compute the weight matrix for the clusterpath (clustering) weights
# without enforcing connectedness
W_cpath <- clusterpath_weights(S, phi = 1, k = 1, connected = FALSE)

# The smallest number of clusters is 2
min_clusters(W_cpath)


# Compute the weight matrix for the clusterpath (clustering) weights
# with enforcing connectedness (default behavior)
W_cpath <- clusterpath_weights(S, phi = 1, k = 1, connected = TRUE)

# The smallest number of clusters is 1
min_clusters(W_cpath)