% drops every other magnitude
function a = drop_odds(b)
%lf = length(b);
%a = [1:lf];
%a = a';
%for i=1:2:lf-1
%   a(i,1) = b(i);
%   a(i+1,1) = b(i);
%end

%experimental, keeps sign
lf = length(b);
a = [1:lf];
a = a';
for i=1:2:lf-1
   a(i,1) = b(i);
   a(i+1,1) = b(i+1)/b(i+1)*abs(b(i));
end


