comparison toolboxes/MIRtoolbox1.3.2/somtoolbox/som_dmatminima.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function minima = som_dmatminima(sM,U,Ne)
+
+%SOM_DMATMINIMA Find clusters based on local minima of U-matrix.
+%
+% minima = som_dmatminima(sM,[U],[Ne])
+%
+%  Input and output arguments ([]'s are optional):
+%   sM         (struct) map struct
+%   U          (matrix) the distance matrix from which minima is
+%                       searched from 
+%                       size msize(1) x ... x msize(end) or 
+%                            2*msize(1)-1 x 2*msize(2)-1 or 
+%                            munits x 1
+%   Ne         (matrix) neighborhood connections matrix
+%
+%   minima     (vector) indeces of the map units where locla minima of
+%                       of U-matrix (or other distance matrix occured)
+%   
+% See also KMEANS_CLUSTERS, SOM_CLLINKAGE, SOM_CLSTRUCT.
+
+% Copyright (c) 2000 by Juha Vesanto
+% Contributed to SOM Toolbox on June 16th, 2000 by Juha Vesanto
+% http://www.cis.hut.fi/projects/somtoolbox/
+ 
+% Version 2.0beta juuso 220800
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% map 
+if isstruct(sM), 
+  switch sM.type, 
+   case 'som_map',  M = sM.codebook; mask = sM.mask; 
+   case 'som_data', M = sM.data; mask = ones(size(M,2),1);
+  end
+else
+  M = sM; mask = ones(size(M,2),1);
+end
+[munits dim] = size(M);
+
+% distances between map units
+if nargin<2, U = []; end
+
+% neighborhoods 
+if nargin<3, Ne = som_neighbors(sM); end
+
+% distance matrix
+if nargin<2 | isempty(U), U = som_dmat(sM,Ne,'median'); end
+if prod(size(U))>munits, U = U(1:2:size(U,1),1:2:size(U,2)); end
+U = U(:); 
+if length(U) ~= munits, error('Distance matrix has incorrect size.'); end
+
+% find local minima
+minima = []; 
+for i=1:munits, 
+  ne = find(Ne(i,:));
+  if all(U(i)<=U(ne)) & ~anycommon(ne,minima), minima(end+1)=i; end
+end
+
+return; 
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+function t = anycommon(i1,i2)
+  if isempty(i1) | isempty(i2), t = 0; 
+  else 
+    m = max(max(i1),max(i2));
+    t = any(sparse(i1,1,1,m,1) & sparse(i2,1,1,m,1)); 
+  end
+  return;   
+