% output k-nearest neighbors adjacency matrix
function A = knn(X,k,beta)

if (nargin < 2)
  k    = 4;  % nearest neighbors
end
if (nargin < 3)
  beta = 1;  % weight exponent
end

fprintf(1,'Nearest Neighbors: %d Beta: %2.3f\n', k, beta);
W = weights(X,k,beta); % Unnormalized transfer weights
A = sign(W);
[r,c] = size(A);
% open output fid
out = sprintf('k%dnn.txt', k);
fid = fopen(out, 'w');
for i=1:r
    for j=1:c
        fprintf(fid,'%d ', A(i,j));
    end;
    fprintf(fid,'\n');
end;
fclose(fid);