Comp-phys-alps-users

comp-phys-alps-users@lists.phys.ethz.ch

April 2017

2 participants
2 discussions

measuring truncation errors in mps_optim
by Robertson Esperanza 07 Dec '17

07 Dec '17

Thank you for all the help so far, now I'm trying to check for convergence of my results. First, is it enough to just check how the truncation error changes with sweeps (at a certain MAXSTATE value) or I need to both check the iteration history of the ground state energy and the truncation error? Second, checking the supplementary materials provided (Computer Physics Communications 185 (2014) 3430–3440) for the Hubbard ladder, why are there 381 values of energy and truncation weights for every iteration? Why is the total truncation error for that iteration is the sum of all the 381 truncation weight values (based on iteration.py)? How is truncation error defined (e.g. is it 1 - sum of all reduced density eigenvalues corresponding to all the picked states?) ? As far as I understand the DMRG algorithm every iteration/sweep has a corresponding bond dimension in which as you progress through iterations (until you reach the "SWEEPS"th iteration), bond dimension increases until you reach "MAXSTATES" at the "SWEEPS"th iteration. Regards, Robertson Esperanza

4 10

Question on harmonic trap in mps_optim
by xiaofanlaohu 12 Apr '17

12 Apr '17

Dear all, I define a lattice with harmonic trap. In the lattice one cell has two subsite A and B. When I use the mps_optim to calculate a lattice. There exist error "Segmentation fault (core dumped)". I want to know how to solve the problem. All files are attached. Thanks! Best, Xiaofan 2017-03-30 xiaofanlaohu

2 2