%% EXPANDER: y=expander(x,L) % When x is a vector, this function adds L-1 after each element of x. % When x is a matrix, each column of it treated as vector and expanded L% fold.function y=expander(x,L)[M,N]=size(x);if (N==1)|(M==1)    if M<N        y=zeros(1,N*L);        y(1:L:end)=x;    else        y=zeros(M*L,1);        y(1:L:end)=x;    endelse    y=zeros(M*L,N);    y(1:L:end,:)=x;end