Dear all My goal is to calculate measures of entanglement (like negativity, concurrence and single site entropy) in DMRG. How is it possible in ALPS DMRG? Is there any way to have the reduced density matrix? In spin 1/2 the density matrix could be expressed in terms of pauli matrices, so the single site entropy could be calculated in an indirect way. But for negativity, specially for spin 1, I have no idea. Thank you kindly for your help in advance. Best Majid Abedi