dan@0: function y=stacklp(x,N)
dan@0: 
dan@0: if nargin<2,
dan@0:   N=5;
dan@0: end
dan@0: 
dan@0: [D,T]=size(x);
dan@0: xext=x(:,[ones(1,N) 1:T T*ones(1,N)]);
dan@0: 
dan@0: y=zeros((2*N+1)*D,T);
dan@0: if islogical(x), y=logical(y);end % copy logical property
dan@0: for k=0:2*N,
dan@0:   y(k*D+(1:D),:)=xext(:,k+1:k+T);
dan@0: end