function Ltv = totvarL(N)
Ldim = 2^N-1;
Ltv = zeros(2*Ldim,N);
rind = 0;
for i=2:2^N
  setstr = dec2bin(i-1,N);
  ii1 = find(setstr=='1');
  rind = rind+1;
  Ltv(rind,ii1) = ones(size(ii1));
  rind = rind+1;
  Ltv(rind,ii1) = -ones(size(ii1));
end
return