The file test_ds_optzeros.mat was generated with the following code:

res = struct();
for j=1:14,
    field = strcat('n', int2str(j));
    a = []
    for opt=0:2,    
        a = [a, ds_optzeros(j, opt)];
    res.(field) = a;
    end
end

And then exporting the variable res.
