function Y = diffumap(B)
n = size(B,1);
W = exp(-0.05*squareform(pdist(B)).^2); % 0.05 和 2 可以改成其他數字試試看
P = diag(1./sum(W,1))*W;
[V,L,U]=eig(P); % The eigenvalues will be arranged in decreasing order
Y = U*L;
hold on;
for i=1:n
plot3(Y(i,1),Y(i,2),Y(i,3),'.', 'MarkerSize', 12, 'Color',[1-i/n 0.8 i/n]);
end