function [X,T]=lagX(S,k)
% Inpute time vector S, tap delay k.
% Output k-dimensional X and one dimensional target T.

S=S(:)';  %Make sure S is a row vector.
p=length(S);
X=zeros(k,p-k);
for j=1:k
    X(j,:)=S(j:p-(k+1-j));
end
T=S(k+1:p);

end