H!

I would like to do an infinite DMRG implementation for a fermionic Hamiltonian with spin. It is not clear to me how to construct an MPO for this model. I have gone through the sample file Heisenberg .h, but it would be really helpful if you could point me to some documentation or sample code on implementing iDMRG for fermions.

I want to be able to get the correlations in the asymptotic limit so is it better to do finite DMRG and a finite-size scaling or should I use infinite dmrg for this purpose? Also will iDMRG algorithm work for systems with impurities ?

Thank You!