Dear all,
I try to use mps_optim for the 1D Bose-Hubbard model in the presence of a trapping potential. I use the latest SVN version (from last week), the latticel model "inhomogeneous chain lattice" and a homemade model "harm boson Hubbard" with the site term: -mu#*n(i)+U#*n(i)*(n(i)-1)/2+K#*n(i)*(x-0.5*(L-1))^2 which differs simply from the usual Bose-Hubbard model by the addition of the last term K#*n(i)*(x-0.5*(L-1))^2. Such a model works with the worm QMC algorithm, but fails with mps_optim with the error message: Exception thrown: Cannot evaluate x I tried to replace "x" by "i" without success.
How should I proceed to have mps_optim work for an inhomogeneous system? More generally, I find it always **VERY** difficult to obtain the information on what should work for a specific algorithm/model in ALPS and what should not work. The only solution I found is trial and error, which is a bit frustrating.
Thanks in advance for your answer(s).
Dominique
Dear Dominique,
If you send the parameters and model files we could help you more. I’m currently away, I won’t be able to try it out before next week.
Did you try already if the model works with the fulldiag, sparsediag and dmrg applications?
Best regards, Michele
-- ETH Zurich Michele Dolfi Institute for Theoretical Physics HIT G 32.4 Wolfgang-Pauli-Str. 27 8093 Zurich Switzerland
dolfim@phys.ethz.ch www.itp.phys.ethz.ch
+41 44 633 78 56 phone +41 44 633 11 15 fax
On 23 Jul 2015, at 14:56, Dominique Delande Dominique.Delande@lkb.upmc.fr wrote:
Dear all,
I try to use mps_optim for the 1D Bose-Hubbard model in the presence of a trapping potential. I use the latest SVN version (from last week), the latticel model "inhomogeneous chain lattice" and a homemade model "harm boson Hubbard" with the site term: -mu#*n(i)+U#*n(i)*(n(i)-1)/2+K#*n(i)*(x-0.5*(L-1))^2 which differs simply from the usual Bose-Hubbard model by the addition of the last term K#*n(i)*(x-0.5*(L-1))^2. Such a model works with the worm QMC algorithm, but fails with mps_optim with the error message: Exception thrown: Cannot evaluate x I tried to replace "x" by "i" without success.
How should I proceed to have mps_optim work for an inhomogeneous system? More generally, I find it always **VERY** difficult to obtain the information on what should work for a specific algorithm/model in ALPS and what should not work. The only solution I found is trial and error, which is a bit frustrating.
Thanks in advance for your answer(s).
Dominique
Dominique Delande (Dominique.Delande@lkb.upmc.fr) Laboratoire Kastler-Brossel - Case 74 - Universite P. et M. Curie 4, place Jussieu, F-75252 Paris Cedex 05, FRANCE Phone : +33 1 44 27 27 97 - Fax : +33 1 44 27 38 45 Acces : Tour 13, Couloir 12-13, 3eme etage - Bureau 316
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