This function calculates the Ward aggregation measures between pairs of singletons.
wardinit(D, wt = NULL)a object of class "dist" with the dissimilarities between the n obsevations.
The function as.dist can be used to transform an object of class matrix to object of class "dist".
vector with the weights of the observations. By default, wt=NULL corresponds to the case where all observations are weighted by 1/n.
Returns an object of class dist with the Ward aggregation measures between the n singletons.
The Ward agreggation measure between to singletons i and j weighted by wi and wj is : (wiwj)/(wi+wj)dij^2 where dij is the dissimilarity between i and j.
M. Chavent, V. Kuentz-Simonet, A. Labenne, J. Saracco. ClustGeo: an R package for hierarchical clustering with spatial constraints. Comput Stat (2018) 33: 1799-1822.