A=[2,5,7; 3,0,1; 9,17,23]
k = spdiags(rot90(A));
s = size(k);
nns = nan(s);
ptr = tril(triu(ones(s)),s(1)-1);
nns(ptr>0) = k(ptr>0);
nns(:,1:2:end) = nns(end:-1:1,1:2:end);
out = sort(ptr,'descend');
out(out>0) = nns(~isnan(nns));
out = out';
or
A=[2,5,7; 3,0,1; 9,17,23];
ds = spdiags(rot90(A));
l = spdiags(ones(size(A)));
ds(:,1:2:end) = flipud(ds(:,1:2:end));
l(:,1:2:end) = flipud(l(:,1:2:end));
l2 = sort(l,'descend');
l2(l2>0) = ds(l>0);
out = l2';
