function [e, E] = xialpha(net)


%            

alpha = abs(net.w)';

idx = find(alpha > 1e-12);

% compute xi

xi = 1 - sign(net.w(idx)').*fwd(net, net.sv(idx,:));

xi(find(xi < 0)) = 0.0;

% compute xi-alpha estimate of leave-one-out cross-validation error

E = zeros(size(alpha));
E(idx) = 2.*alpha(idx).*r(net.kernel) + xi;
e = E >= 1;