calculates distances between observations, then plots the classification tree as a dendrogram
[x_dist,x_link] = dendro(x,(dist_type),(nbr_groups))
a matrix (n x q) or a Div
the distance method chosen
'euc'=classical euclidian (default), 'mah' = Mahalanobis, 'cit','cor','ham','jac',min','seu'
number of groups represented by the dendrogram
- if too many observations to be represented -