%PLOTDG Plot dendrogram
%
% PLOTDG(DENDROGRAM,K,FLIP)
%
% INPUT
% DENDROGRAM Dendrogram
% K Number of clusters
% FLIP FALSE (default) or TRUE
%
% OUTPUT
%
% DESCRIPTION
% Plots a dendrogram as generated by HCLUST. If the optional K is given the
% dendrogram is compressed first to K clusters. Along the horizontal axis
% the numbers stored in DENDROGRAM(1,:) are written as text. The dendrogram
% itself is defined by DENDROGRAM(2,:) in which each entry stands for the
% level on which the previous and next group of objects are clustered.
%
% SEE ALSO (<a href="http://37steps.com/prtools">PRTools Guide</a>)
% HCLUST
% Copyright: R.P.W. Duin, duin@ph.tn.tudelft.nl
% Faculty of Applied Sciences, Delft University of Technology
% P.O. Box 5046, 2600 GA Delft, The Netherlands
% $Id: plotdg.m,v 1.2 2006/03/08 22:06:58 duin Exp $
function plotdg(varargin)
[dendrogram,k,flip] = setdefaults(varargin,[],[],false);
if isempty(dendrogram)
error('No proper dendrogram supplied')
end
[n,m] = size(dendrogram);
if isempty(k), k = m; end
if k < m % compress dendrogram to k clusters
F = [dendrogram(2,:),inf];
S = sort(-F); t = -S(k+1); % find cluster level
I = [find(F >= t),m+1]; % find all indices where cluster starts
dendrogram = [I(2:k+1) - I(1:k); F(I(1:k))];
m = k;
elseif k > m
error('Number of clusters should be less than sample size')
end
[S,I] = sort(dendrogram(2,:));
C = [0:m-1;1:m;zeros(1,m);2:m+1];
X = zeros(m,4); Y = X;
T = zeros(m,4);
for i=1:m-1
X(i,:) = [C(2,I(i)), C(2,I(i)), C(2,C(1,I(i))), C(2,C(1,I(i)))];
Y(i,:) = [C(3,I(i)), S(i), S(i), C(3,C(1,I(i)))];
C(:,C(1,I(i))) = [C(1,C(1,I(i))), (C(2,I(i)) + C(2,C(1,I(i))))/2, ...
S(i), C(4,I(i))]';
C(1,C(4,I(i))) = C(1,I(i));
T(i,:) = sprintf('%4d',dendrogram(1,i));
end
T(m,:) = sprintf('%4d',dendrogram(1,m));
T = char(T);
h = gca;
if flip
X(m,:) = [0 0 m+1 m+1];
Y(m,:) = [0 0 0 0];
plot(Y',X','-b');
set(h,'ytick',[1:m]);
set(h,'yticklabel',T);
axis([0,max(max(Y))*1.05,0,m+1])
else
X(m,:) = [0 0 m+1 m+1];
Y(m,:) = [0 0 0 0];
plot(X',Y','-b');
set(h,'xtick',[1:m]);
set(h,'xticklabel',T);
axis([0,m+1,0,max(max(Y))*1.05])
end
set(h,'box','off');
set(h,'fontsize',8)
return