function Ne = som_neighbors(sM,neigh)% Ne = som_neighbors(sM,neigh)%% sM      (struct) map or data struct%         (matrix) data matrix, size n x dim% [neigh] (string) 'kNN' or 'Nk' (which is valid for a SOM only)%                  for example '6NN' or 'N1'%                  default is '10NN' for a data set and 'N1' for SOM%% Ne      (matrix) size n x n, a sparse matrix%                  indicating the neighbors of each sample by value 1 %                  (note: the unit itself also has value 0)%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%if isstruct(sM),   switch sM.type,    case 'som_map',  M = sM.codebook;    case 'som_data', M = sM.data; sM = [];   endelse  M = sM;   sM = []; endn = size(M,1);if nargin<2,   if isempty(sM), neigh = '10NN'; else neigh = 'N1'; endendif strcmp(neigh(end-1:end),'NN'),  k  = str2num(neigh(1:end-2));  kmus = som_bmus(M,M,1:k+1);  Ne = sparse(n,n);  for i=1:n, Ne(i,kmus(i,:)) = 1; endelse  if ~isstruct(sM), error('Prototypes must be in a map struct.'); end        k  = str2num(neigh(2:end));  N1 = som_unit_neighs(sM);      Ne = sparse(som_neighborhood(N1,k)<=k);endNe([0:n-1]*n+[1:n]) = 0; % remove self from neighborsreturn;