October 2017 - Comp-phys-alps-users

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

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mpirun
by Tadeusz Wasiutyński 22 Nov '17

22 Nov '17

I have installed alps with Conda. Now I can not figure out how to run it mpi mode: mpirun not found. Previously I always build from source and put some parameters in cmake command. What can I do now? -- Tadeusz Wasiutyński

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Problem with DMRG
by Natanael de Carvalho Costa 27 Oct '17

27 Oct '17

Dear All, I'm trying to get some results for the Periodic Anderson model (PAM) using DMRG. Precisely, I'm trying to analyze the PAM with crossed hybridizations. However, I'm getting different results for symmetric situations, where they must be equal. I will try to explain it below. In order to have the crossed PAM, I first created the lattice below. <LATTICES> <LATTICEGRAPH name="PAM_cross"> <FINITELATTICE> <LATTICE dimension="1"> <BASIS> <VECTOR>1</VECTOR> </BASIS> </LATTICE> <PARAMETER name="L"/> <EXTENT size="L"/> <BOUNDARY type="open"/> </FINITELATTICE> <UNITCELL dimension="1" vertices="2"> <VERTEX id="1" type="0"> </VERTEX> <VERTEX id="2" type="1"> </VERTEX> <EDGE type="2"> <SOURCE vertex="1"/><TARGET vertex="2"/> </EDGE> <EDGE type="1"> <SOURCE vertex="1"/><TARGET vertex="1" offset="1"/> </EDGE> <EDGE type="3"> <SOURCE vertex="1"/><TARGET vertex="2" offset="1"/> </EDGE> <EDGE type="4"> <SOURCE vertex="2"/><TARGET vertex="1" offset="1"/> </EDGE> </UNITCELL> </LATTICEGRAPH> </LATTICES> where vertex '0' and '1' will describe d- and f-electrons, respectively. Furthermore, the edge '1' will correspond to the hopping of d-electrons, edge '2' the local hybridization, and edges '3' and "4" the crossed hybridizations. I chose the "alternative fermion Hubbard" Hamiltonian, since I'm interested to conserve the total number of particles operator. In this notation, I have t1=t, t2=V_local, t3=Vcross1 and t4=V_cross2. My first test was for t1=1, t2=t4=0.75 and t3=0, which corresponds to a sawtooth chain. Notice that in this case exchanging the index 3 and 4 (i.e. making t3=0.75 and t4=0) just reflects the lattice, and should not have any physical effect. Thus, the results *must* be the same. However, I getting different results for these two cases in a vast variety of parameters. For instance, fixing SWEEPS=5 MAXSTATES=100 CONSERVED_QUANTUMNUMBERS= "N" N_total = 24; L=12; t1=1.0; t2=0.75; t4=0.0; U0=0.0; U1=1.0; mu1=0.5; {t3=0.75;} I get E=-31.251093744938501. But for t3=0 and t4=0.75, it is -31.785332039272376. I checked it with an old code I have, and the latter is the right one. So, do you know what is happening? Did I do something wrong? I appreciate if you can help me with it. Thanks in advance. I look forward to hearing from you in due course. Yours Sincerely, Natanael C. Costa

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mpirun
by Tadeusz Wasiutyński 27 Oct '17

27 Oct '17

Hello, sorry for being not precise enough. I did install mpirun by conda but the response is: This program has not been compiled for use with MPI is it so or I made some mistake when installing alps by conda. BTW alps works smoothly otherwise. Regards 2017-10-25 12:00 GMT+02:00 <comp-phys-alps-users-request(a)lists.phys.ethz.ch> : > Send Comp-phys-alps-users mailing list submissions to > comp-phys-alps-users(a)lists.phys.ethz.ch > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.phys.ethz.ch/listinfo/comp-phys-alps-users > or, via email, send a message with subject or body 'help' to > comp-phys-alps-users-request(a)lists.phys.ethz.ch > > You can reach the person managing the list at > comp-phys-alps-users-owner(a)lists.phys.ethz.ch > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Comp-phys-alps-users digest..." > > Today's Topics: > > 1. mpirun (Tadeusz Wasiuty?ski) > > > ---------- Wiadomość przekazana dalej ---------- > From: "Tadeusz Wasiutyński" <tadeusz.wasiutynski(a)gmail.com> > To: comp-phys-alps-users(a)lists.phys.ethz.ch > Cc: > Bcc: > Date: Tue, 24 Oct 2017 22:02:34 +0200 > Subject: [ALPS-users] mpirun > I have installed alps with Conda. Now I can not figure out how to run it > mpi mode: mpirun not found. Previously I always build from source and put > some parameters in cmake command. What can I do now? > > -- > Tadeusz Wasiutyński > > ---- > Comp-phys-alps-users Mailing List for the ALPS Project > http://alps.comp-phys.org/ > > List info: https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users > Archive: https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users > > Unsubscribe by writing a mail to comp-phys-alps-users-leave@ > lists.phys.ethz.ch. > -- Tadeusz Wasiutyński

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