Mclust {mclust}R Documentation

Model-Based Clustering

Description

The optimal model according to BIC for EM initialized by hierarchical clustering for parameterized Gaussian mixture models.

Usage

Mclust(data, G=NULL, modelNames=NULL, prior=NULL, control=emControl(), 
       initialization=NULL, warn=FALSE, ...)

Arguments

data A numeric vector, matrix, or data frame of observations. Categorical variables are not allowed. If a matrix or data frame, rows correspond to observations and columns correspond to variables.
G An integer vector specifying the numbers of mixture components (clusters) for which the BIC is to be calculated. The default is G=1:9.
modelNames A vector of character strings indicating the models to be fitted in the EM phase of clustering. The help file for mclustModelNames describes the available models. The default is c("E", "V") for univariate data and mclustOptions()\$emModelNames for multivariate data (n > d), the spherical and diagonal models c("EII", "VII", "EEI", "EVI", "VEI", "VVI") for multivariate data (n <= d).
prior The default assumes no prior, but this argument allows specification of a conjugate prior on the means and variances through the function priorControl.
control A list of control parameters for EM. The defaults are set by the call emControl().
initialization A list containing zero or more of the following components:
    hcPairs
    A matrix of merge pairs for hierarchical clustering such as produced by function hc. For multivariate data, the default is to compute a hierarchical clustering tree by applying function hc with modelName = "VVV" to the data or a subset as indicated by the subset argument. The hierarchical clustering results are to start EM. For univariate data, the default is to use quantiles to start EM.
    subset
    A logical or numeric vector specifying a subset of the data to be used in the initial hierarchical clustering phase.
warn A logical value indicating whether or not certain warnings (usually related to singularity) should be issued. The default is to suppress these warnings.
... Catches unused arguments in indirect or list calls via do.call.

Value

A list giving the optimal (according to BIC) parameters, conditional probabilities z, and loglikelihood, together with the associated classification and its uncertainty. The details of the output components are as follows:

modelName A character string denoting the model at which the optimal BIC occurs.
n The number of observations in the data.
d The dimension of the data.
G The optimal number of mixture components.
BIC All BIC values.
bic Optimal BIC value.
loglik The loglikelihood corresponding to the optimal BIC.
z A matrix whose [i,k]th entry is the probability that observation i in the test data belongs to the kth class.
classification map(z): The classification corresponding to z.
uncertainty The uncertainty associated with the classification.
Attributes: The input parameters other than the data.

References

C. Fraley and A. E. Raftery (2002). Model-based clustering, discriminant analysis, and density estimation. Journal of the American Statistical Association 97:611:631.

C. Fraley and A. E. Raftery (2005). Bayesian regularization for normal mixture estimation and model-based clustering. Technical Report, Department of Statistics, University of Washington.

C. Fraley and A. E. Raftery (2006). MCLUST Version 3 for R: Normal Mixture Modeling and Model-Based Clustering, Technical Report no. 504, Department of Statistics, University of Washington.

See Also

priorControl, emControl, mclustBIC, mclustModelNames, mclustOptions

Examples

irisMclust <- Mclust(iris[,-5])
## Not run: 
 plot(irisMclust)
## End(Not run)

[Package mclust version 3.1-10.3 Index]