lize a random subset of the data as a single image
perm = randperm(n);
figure(1); clf
%K = 24; %XX = reshape(X(perm(1:K),:)', [h w 1 K]); montage(XX)
%title(sprintf('%d random training images', K))
for i=1:25
  subplot(5,5,i)
  f = reshape(X(perm(i),:), [h w]);
  imagesc(f);  axis off; colormap gray
end
printPmtkFigure(sprintf('pcaImages-%s-images',name)); 

mu = mean(X);
XC = X-repmat(mu,size(X,1),1);
sprintf('Performing PCA.... stay tuned\n');
%[U,S,V] = svd(XC,0);
%evals = (1/n)*diag(S).^2;
[V, Z, evals]