function [r]=dsdemode(c,y)
% c1=repmat(c',1,length(y)/length(c));
% tmp=y.*c1;
% r=tmp(1:length(c):length(tmp));
tmp = reshape(y, length(c), length(y)/length(c));
tmp = tmp';
%x is a column vector
x = tmp * c;
% convert to row vector
r = x';