### Infinite DMRG state prediction

Posted:

**04 Dec 2018, 21:09**Hi Johannes,

I'm studying your tenpy/algorithms/dmrg.py code and I'd like to ask which part/lines of this code implements the state prediction method shown in chapters 10.2 and 10.3 of Shollwock's paper (Annals of Physics 326 (2011) 96–192)? Specifically, there should be some term at the end of each left and right sweep that substitutes the Schmidt value \lambda with

\lambda^[l+1]_guess = \lambda^[l]_R x [\lambda^[l-1]]^{-1} x \lambda^l_L

(Eq. 338 of the paper) for the subsequent iteration's guess wavefunction. Could you please tell me where this is done in this code? There is something resembling this in the code toycodes/d_dmrg.py at line 109 for a 2 site unit cell.

Also, could you please explain how one could generalize the code toycode/d_dmrg.py for larger/arbitrary unit cell sizes? Many thanks.

Regards,

Jason

I'm studying your tenpy/algorithms/dmrg.py code and I'd like to ask which part/lines of this code implements the state prediction method shown in chapters 10.2 and 10.3 of Shollwock's paper (Annals of Physics 326 (2011) 96–192)? Specifically, there should be some term at the end of each left and right sweep that substitutes the Schmidt value \lambda with

\lambda^[l+1]_guess = \lambda^[l]_R x [\lambda^[l-1]]^{-1} x \lambda^l_L

(Eq. 338 of the paper) for the subsequent iteration's guess wavefunction. Could you please tell me where this is done in this code? There is something resembling this in the code toycodes/d_dmrg.py at line 109 for a 2 site unit cell.

Also, could you please explain how one could generalize the code toycode/d_dmrg.py for larger/arbitrary unit cell sizes? Many thanks.

Regards,

Jason