Comp-phys-alps-users

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Re: [ALPS-users] complexity estimation for the 3D ferromagnetic Heisenberg model
by Menchyshyn Oleh 02 Oct '14

02 Oct '14

Dear Synge, thank you for your attention. So in my case, having the lattice with 16 atoms unit cell and 48 intra and intercell bonds (coupling constants), means I would need to multiply the estimated expected time for some simple reference model by 48? The THERMALIZATION and SWEEPS parameters are chosen to meet the relative errors set up for observables being measured. If we increase the size of the system, namely L=8,12,16,24,..., but leave the SWEEPS the same, the relative error increases and the accuracy of simulation drops, aren't they? I'm asking that to clarify the issue as the cluster I use limits the jobs running time to 48 hours. And is it possible in principle in ALPS to stop the calculation and restart later as a new process? Or in that case when I need to analyse the QMC statistics manually? > Dear Oleh, > > I think that the default value (SWEEPS = 65536, THERMALIZATION = SWEEPS/8) > should be enough > for rough estimation of the critical temperature of simple models. > > The CPU time of the looper code is asymptotically proportional to the > number of bonds (more precisely, > the sum of coupling constants) and as well as to the inverse temperature. > For example, QMC calculation > of simple cubic S=1/2 ferromagnetic Heisenberg model near the Curie point > (T \sim 0.8) takes about > > 16 sec (for L=8) > 52 sec (for L=12) > 134 sec (for L=16) > 450 sec (for L=24) > 1490 sec (for L=36) > > on my x86 workstation. > > Best, > Synge > > > On 2014/10/01, at 3:40, Menchyshyn Oleh <oleh.menchyshyn(a)gmail.com> wrote: > > > Dear Synge, > > > > thank you for your hints. It works nice. > > I think, it would be useful to update the tutorial on that subject, to > make it more clear, > > that parameter file is not the lattice description one. > > I knew it was the two-dimensional model. I put it on purpose, just as an > example. > > > > Can someone experienced in QMC-loop simulations comment on my bigger > problem, please. > > > > > > Message: 10 > > Date: Mon, 29 Sep 2014 11:03:36 +0900 > > From: Synge Todo <wistaria(a)comp-phys.org> > > To: comp-phys-alps-users(a)lists.phys.ethz.ch > > Subject: Re: [ALPS-users] complexity estimation for the 3D > > ferromagnetic Heisenberg model > > Message-ID: <9E0990A4-3582-45B9-B8C6-F704BE452A27(a)comp-phys.org> > > Content-Type: text/plain; charset=windows-1252 > > > > Dear Oleh, > > > > It seems that your lattice ?p_lat? is not defined in THREE dimensions, > but in TWO dimensions. > > Are you really simulating three-dimensional model? > > > > Best, > > Synge > > > > > > On 2014/09/29, at 5:09, Menchyshyn Oleh <oleh.menchyshyn(a)gmail.com> > wrote: > > > > > Dear ALPS community, > > > > > > I am trying to obtain the critical temperature for the 3D > ferromagnetic Heisenberg model S=1/2 on the cubic lattice with a unit cell > which contains 16 atoms. I have made the QMC "loop" simulations for the > lattice with dimensions L = 8, i.e. 8*8*8 unit cells, also for L=10, and > L=12. > > > But there was just a little bend on the magnetisation curve as a sign > of the phase transition which should occur for the ferromagnetic model for > certain. I know I should use the Binder cumulant and the finite size > scaling to locate the phase transition point correctly. > > > I have enlarged my lattice to L=24, but simulation goes very-very > slowly. As I have limited resources to just tens of cores and I have a > feeling I would need to take L=32(48?) at least I want to ask: > > > > > > Based on your experience what order should be the THERMALIZATION and > SWEEPS parameters? > > > How can I estimate the computational complexity of my problem and the > time it would take? > > > Or maybe, I do anything wrong? > > > > > > A one more technical issue. The tutorial on the ALPS says that > correctness of a lattice definition can be checked with "printgraph" tool. > I used it with a couple definition files but all resulted in: > > > > > > Caught exception: parameter parse error at "<LATTICES> <LATTICEGRAPH > name="p" > > > > > > Just for a reference I put a definition of a lattice I know worked > well with simulation tools, but failed with "printgraph" > > > > > > <LATTICES> > > > <LATTICEGRAPH name="p_lat"> > > > <FINITELATTICE> > > > <LATTICE dimension="2"> > > > <BASIS> <VECTOR>1 0</VECTOR><VECTOR>0 1</VECTOR></BASIS> > > > </LATTICE> > > > <PARAMETER name="L"/> > > > <PARAMETER name="M"/> > > > <EXTENT dimension="1" size="L"/> > > > <EXTENT dimension="2" size="M"/> > > > <BOUNDARY type="periodic"/> > > > </FINITELATTICE> > > > <UNITCELL dimension="2" vertices="6"> > > > <VERTEX id="1"><COORDINATE> 0.6 0.2 </COORDINATE></VERTEX> > > > <VERTEX id="2"><COORDINATE> 0.6 0.6 </COORDINATE></VERTEX> > > > <VERTEX id="3"><COORDINATE> 0.2 0.6 </COORDINATE></VERTEX> > > > <VERTEX id="4"><COORDINATE> 0.2 0.2 </COORDINATE></VERTEX> > > > <VERTEX id="5"><COORDINATE> 0.8 0.4 </COORDINATE></VERTEX> > > > <VERTEX id="6"><COORDINATE> 0.4 0.8 </COORDINATE></VERTEX> > > > <EDGE type="2"><SOURCE vertex="1"/><TARGET vertex="2"/></EDGE> > > > <EDGE type="2"><SOURCE vertex="2"/><TARGET vertex="3"/></EDGE> > > > <EDGE type="2"><SOURCE vertex="3"/><TARGET vertex="4"/></EDGE> > > > <EDGE type="2"><SOURCE vertex="1"/><TARGET vertex="4"/></EDGE> > > > <EDGE type="3"><SOURCE vertex="1"/><TARGET vertex="5"/></EDGE> > > > <EDGE type="3"><SOURCE vertex="2"/><TARGET vertex="6"/></EDGE> > > > <EDGE type="1"><SOURCE vertex="2"/><TARGET vertex="5"/></EDGE> > > > <EDGE type="1"><SOURCE vertex="3"/><TARGET vertex="6"/></EDGE> > > > <EDGE type="3"><SOURCE vertex="3"/><TARGET vertex="5" offset="-1 > 0"/></EDGE> > > > <EDGE type="1"><SOURCE vertex="4"/><TARGET vertex="5" offset="-1 > 0"/></EDGE> > > > <EDGE type="3"><SOURCE vertex="4"/><TARGET vertex="6" offset="0 > -1"/></EDGE> > > > <EDGE type="1"><SOURCE vertex="1"/><TARGET vertex="6" offset="0 > -1"/></EDGE> > > > </UNITCELL> > > > </LATTICEGRAPH> > > > </LATTICES> > > > > > > > > > Best regards, > > > Oleh Menchyshyn >

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Re: [ALPS-users] complexity estimation for the 3D ferromagnetic Heisenberg model
by Menchyshyn Oleh 01 Oct '14

01 Oct '14

Dear Synge, thank you for your hints. It works nice. I think, it would be useful to update the tutorial on that subject, to make it more clear, that parameter file is not the lattice description one. I knew it was the two-dimensional model. I put it on purpose, just as an example. Can someone experienced in QMC-loop simulations comment on my bigger problem, please. > > Message: 10 > Date: Mon, 29 Sep 2014 11:03:36 +0900 > From: Synge Todo <wistaria(a)comp-phys.org> > To: comp-phys-alps-users(a)lists.phys.ethz.ch > Subject: Re: [ALPS-users] complexity estimation for the 3D > ferromagnetic Heisenberg model > Message-ID: <9E0990A4-3582-45B9-B8C6-F704BE452A27(a)comp-phys.org> > Content-Type: text/plain; charset=windows-1252 > > Dear Oleh, > > It seems that your lattice ?p_lat? is not defined in THREE dimensions, but > in TWO dimensions. > Are you really simulating three-dimensional model? > > Best, > Synge > > > On 2014/09/29, at 5:09, Menchyshyn Oleh <oleh.menchyshyn(a)gmail.com> wrote: > > > Dear ALPS community, > > > > I am trying to obtain the critical temperature for the 3D ferromagnetic > Heisenberg model S=1/2 on the cubic lattice with a unit cell which contains > 16 atoms. I have made the QMC "loop" simulations for the lattice with > dimensions L = 8, i.e. 8*8*8 unit cells, also for L=10, and L=12. > > But there was just a little bend on the magnetisation curve as a sign of > the phase transition which should occur for the ferromagnetic model for > certain. I know I should use the Binder cumulant and the finite size > scaling to locate the phase transition point correctly. > > I have enlarged my lattice to L=24, but simulation goes very-very > slowly. As I have limited resources to just tens of cores and I have a > feeling I would need to take L=32(48?) at least I want to ask: > > > > Based on your experience what order should be the THERMALIZATION and > SWEEPS parameters? > > How can I estimate the computational complexity of my problem and the > time it would take? > > Or maybe, I do anything wrong? > > > > A one more technical issue. The tutorial on the ALPS says that > correctness of a lattice definition can be checked with "printgraph" tool. > I used it with a couple definition files but all resulted in: > > > > Caught exception: parameter parse error at "<LATTICES> <LATTICEGRAPH > name="p" > > > > Just for a reference I put a definition of a lattice I know worked well > with simulation tools, but failed with "printgraph" > > > > <LATTICES> > > <LATTICEGRAPH name="p_lat"> > > <FINITELATTICE> > > <LATTICE dimension="2"> > > <BASIS> <VECTOR>1 0</VECTOR><VECTOR>0 1</VECTOR></BASIS> > > </LATTICE> > > <PARAMETER name="L"/> > > <PARAMETER name="M"/> > > <EXTENT dimension="1" size="L"/> > > <EXTENT dimension="2" size="M"/> > > <BOUNDARY type="periodic"/> > > </FINITELATTICE> > > <UNITCELL dimension="2" vertices="6"> > > <VERTEX id="1"><COORDINATE> 0.6 0.2 </COORDINATE></VERTEX> > > <VERTEX id="2"><COORDINATE> 0.6 0.6 </COORDINATE></VERTEX> > > <VERTEX id="3"><COORDINATE> 0.2 0.6 </COORDINATE></VERTEX> > > <VERTEX id="4"><COORDINATE> 0.2 0.2 </COORDINATE></VERTEX> > > <VERTEX id="5"><COORDINATE> 0.8 0.4 </COORDINATE></VERTEX> > > <VERTEX id="6"><COORDINATE> 0.4 0.8 </COORDINATE></VERTEX> > > <EDGE type="2"><SOURCE vertex="1"/><TARGET vertex="2"/></EDGE> > > <EDGE type="2"><SOURCE vertex="2"/><TARGET vertex="3"/></EDGE> > > <EDGE type="2"><SOURCE vertex="3"/><TARGET vertex="4"/></EDGE> > > <EDGE type="2"><SOURCE vertex="1"/><TARGET vertex="4"/></EDGE> > > <EDGE type="3"><SOURCE vertex="1"/><TARGET vertex="5"/></EDGE> > > <EDGE type="3"><SOURCE vertex="2"/><TARGET vertex="6"/></EDGE> > > <EDGE type="1"><SOURCE vertex="2"/><TARGET vertex="5"/></EDGE> > > <EDGE type="1"><SOURCE vertex="3"/><TARGET vertex="6"/></EDGE> > > <EDGE type="3"><SOURCE vertex="3"/><TARGET vertex="5" offset="-1 > 0"/></EDGE> > > <EDGE type="1"><SOURCE vertex="4"/><TARGET vertex="5" offset="-1 > 0"/></EDGE> > > <EDGE type="3"><SOURCE vertex="4"/><TARGET vertex="6" offset="0 > -1"/></EDGE> > > <EDGE type="1"><SOURCE vertex="1"/><TARGET vertex="6" offset="0 > -1"/></EDGE> > > </UNITCELL> > > </LATTICEGRAPH> > > </LATTICES> > > > > > > Best regards, > > Oleh Menchyshyn > > > > ------------------------------ > > Message: 11 > Date: Mon, 29 Sep 2014 11:44:07 +0900 > From: Synge Todo <wistaria(a)comp-phys.org> > To: comp-phys-alps-users(a)lists.phys.ethz.ch > Subject: Re: [ALPS-users] complexity estimation for the 3D > ferromagnetic Heisenberg model > Message-ID: <1DFD019C-D86C-4BB5-8152-974E17F7B366(a)comp-phys.org> > Content-Type: text/plain; charset=windows-1252 > > Dear Oleh, > > As for ?printgraph? tool, you have to specify the name of parameter file > (not lattice file). > Please prepare a parameter file (say, ?parms?) that includes, e.g. > > LATTICE_LIBRARY = "lattice.xml" > LATTICE = "p_lat" > L = 4 > M = 4 > > and execute printgraph tool with the following command line option: > > printgraph parms > > Best, > Synge > > > On 2014/09/29, at 11:03, Synge Todo <wistaria(a)comp-phys.org> wrote: > > > Dear Oleh, > > > > It seems that your lattice ?p_lat? is not defined in THREE dimensions, > but in TWO dimensions. > > Are you really simulating three-dimensional model? > > > > Best, > > Synge > > > > > > On 2014/09/29, at 5:09, Menchyshyn Oleh <oleh.menchyshyn(a)gmail.com> > wrote: > > > >> Dear ALPS community, > >> > >> I am trying to obtain the critical temperature for the 3D ferromagnetic > Heisenberg model S=1/2 on the cubic lattice with a unit cell which contains > 16 atoms. I have made the QMC "loop" simulations for the lattice with > dimensions L = 8, i.e. 8*8*8 unit cells, also for L=10, and L=12. > >> But there was just a little bend on the magnetisation curve as a sign > of the phase transition which should occur for the ferromagnetic model for > certain. I know I should use the Binder cumulant and the finite size > scaling to locate the phase transition point correctly. > >> I have enlarged my lattice to L=24, but simulation goes very-very > slowly. As I have limited resources to just tens of cores and I have a > feeling I would need to take L=32(48?) at least I want to ask: > >> > >> Based on your experience what order should be the THERMALIZATION and > SWEEPS parameters? > >> How can I estimate the computational complexity of my problem and the > time it would take? > >> Or maybe, I do anything wrong? > >> > >> A one more technical issue. The tutorial on the ALPS says that > correctness of a lattice definition can be checked with "printgraph" tool. > I used it with a couple definition files but all resulted in: > >> > >> Caught exception: parameter parse error at "<LATTICES> <LATTICEGRAPH > name="p" > >> > >> Just for a reference I put a definition of a lattice I know worked well > with simulation tools, but failed with "printgraph" > >> > >> <LATTICES> > >> <LATTICEGRAPH name="p_lat"> > >> <FINITELATTICE> > >> <LATTICE dimension="2"> > >> <BASIS> <VECTOR>1 0</VECTOR><VECTOR>0 1</VECTOR></BASIS> > >> </LATTICE> > >> <PARAMETER name="L"/> > >> <PARAMETER name="M"/> > >> <EXTENT dimension="1" size="L"/> > >> <EXTENT dimension="2" size="M"/> > >> <BOUNDARY type="periodic"/> > >> </FINITELATTICE> > >> <UNITCELL dimension="2" vertices="6"> > >> <VERTEX id="1"><COORDINATE> 0.6 0.2 </COORDINATE></VERTEX> > >> <VERTEX id="2"><COORDINATE> 0.6 0.6 </COORDINATE></VERTEX> > >> <VERTEX id="3"><COORDINATE> 0.2 0.6 </COORDINATE></VERTEX> > >> <VERTEX id="4"><COORDINATE> 0.2 0.2 </COORDINATE></VERTEX> > >> <VERTEX id="5"><COORDINATE> 0.8 0.4 </COORDINATE></VERTEX> > >> <VERTEX id="6"><COORDINATE> 0.4 0.8 </COORDINATE></VERTEX> > >> <EDGE type="2"><SOURCE vertex="1"/><TARGET vertex="2"/></EDGE> > >> <EDGE type="2"><SOURCE vertex="2"/><TARGET vertex="3"/></EDGE> > >> <EDGE type="2"><SOURCE vertex="3"/><TARGET vertex="4"/></EDGE> > >> <EDGE type="2"><SOURCE vertex="1"/><TARGET vertex="4"/></EDGE> > >> <EDGE type="3"><SOURCE vertex="1"/><TARGET vertex="5"/></EDGE> > >> <EDGE type="3"><SOURCE vertex="2"/><TARGET vertex="6"/></EDGE> > >> <EDGE type="1"><SOURCE vertex="2"/><TARGET vertex="5"/></EDGE> > >> <EDGE type="1"><SOURCE vertex="3"/><TARGET vertex="6"/></EDGE> > >> <EDGE type="3"><SOURCE vertex="3"/><TARGET vertex="5" offset="-1 > 0"/></EDGE> > >> <EDGE type="1"><SOURCE vertex="4"/><TARGET vertex="5" offset="-1 > 0"/></EDGE> > >> <EDGE type="3"><SOURCE vertex="4"/><TARGET vertex="6" offset="0 > -1"/></EDGE> > >> <EDGE type="1"><SOURCE vertex="1"/><TARGET vertex="6" offset="0 > -1"/></EDGE> > >> </UNITCELL> > >> </LATTICEGRAPH> > >> </LATTICES> > >> > >> > >> Best regards, > >> Oleh Menchyshyn >

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complexity estimation for the 3D ferromagnetic Heisenberg model
by Menchyshyn Oleh 29 Sep '14

29 Sep '14

Dear ALPS community, I am trying to obtain the critical temperature for the 3D ferromagnetic Heisenberg model S=1/2 on the cubic lattice with a unit cell which contains 16 atoms. I have made the QMC "loop" simulations for the lattice with dimensions L = 8, i.e. 8*8*8 unit cells, also for L=10, and L=12. But there was just a little bend on the magnetisation curve as a sign of the phase transition which should occur for the ferromagnetic model for certain. I know I should use the Binder cumulant and the finite size scaling to locate the phase transition point correctly. I have enlarged my lattice to L=24, but simulation goes very-very slowly. As I have limited resources to just tens of cores and I have a feeling I would need to take L=32(48?) at least I want to ask: Based on your experience what order should be the THERMALIZATION and SWEEPS parameters? How can I estimate the computational complexity of my problem and the time it would take? Or maybe, I do anything wrong? A one more technical issue. The tutorial on the ALPS says that correctness of a lattice definition can be checked with "printgraph" tool. I used it with a couple definition files but all resulted in: Caught exception: parameter parse error at "<LATTICES> <LATTICEGRAPH name="p" Just for a reference I put a definition of a lattice I know worked well with simulation tools, but failed with "printgraph" <LATTICES> <LATTICEGRAPH name="p_lat"> <FINITELATTICE> <LATTICE dimension="2"> <BASIS> <VECTOR>1 0</VECTOR><VECTOR>0 1</VECTOR></BASIS> </LATTICE> <PARAMETER name="L"/> <PARAMETER name="M"/> <EXTENT dimension="1" size="L"/> <EXTENT dimension="2" size="M"/> <BOUNDARY type="periodic"/> </FINITELATTICE> <UNITCELL dimension="2" vertices="6"> <VERTEX id="1"><COORDINATE> 0.6 0.2 </COORDINATE></VERTEX> <VERTEX id="2"><COORDINATE> 0.6 0.6 </COORDINATE></VERTEX> <VERTEX id="3"><COORDINATE> 0.2 0.6 </COORDINATE></VERTEX> <VERTEX id="4"><COORDINATE> 0.2 0.2 </COORDINATE></VERTEX> <VERTEX id="5"><COORDINATE> 0.8 0.4 </COORDINATE></VERTEX> <VERTEX id="6"><COORDINATE> 0.4 0.8 </COORDINATE></VERTEX> <EDGE type="2"><SOURCE vertex="1"/><TARGET vertex="2"/></EDGE> <EDGE type="2"><SOURCE vertex="2"/><TARGET vertex="3"/></EDGE> <EDGE type="2"><SOURCE vertex="3"/><TARGET vertex="4"/></EDGE> <EDGE type="2"><SOURCE vertex="1"/><TARGET vertex="4"/></EDGE> <EDGE type="3"><SOURCE vertex="1"/><TARGET vertex="5"/></EDGE> <EDGE type="3"><SOURCE vertex="2"/><TARGET vertex="6"/></EDGE> <EDGE type="1"><SOURCE vertex="2"/><TARGET vertex="5"/></EDGE> <EDGE type="1"><SOURCE vertex="3"/><TARGET vertex="6"/></EDGE> <EDGE type="3"><SOURCE vertex="3"/><TARGET vertex="5" offset="-1 0"/></EDGE> <EDGE type="1"><SOURCE vertex="4"/><TARGET vertex="5" offset="-1 0"/></EDGE> <EDGE type="3"><SOURCE vertex="4"/><TARGET vertex="6" offset="0 -1"/></EDGE> <EDGE type="1"><SOURCE vertex="1"/><TARGET vertex="6" offset="0 -1"/></EDGE> </UNITCELL> </LATTICEGRAPH> </LATTICES> Best regards, Oleh Menchyshyn

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antiferromagnetic phase of Hubbard model on Bethe lattice
by Duo Song 23 Sep '14

23 Sep '14

Dear all, I am trying the DMFT CT-HYB, Hirsch-Fye tutorial and I have a question on the antiferromagnetic property of the system. It is said that the system, a Hubbard model on the Bethe lattice with interaction [image: U=3D/\sqrt{2}] at half filling, enters an antiferromagnetic phase upon cooling. In other words, the neighboring sites have only one electron each with opposite spins at low temperature. But the sites of Bethe lattice are independent. How do you get coupling between sites to even know when they are spin alined or not? Best, Duo

2 1

auto-correlation time in hybridization expansion ctqmc calculation
by Jia Chen 21 Sep '14

21 Sep '14

Dear all, I would like to know, if I can have auto-correlation time from hybridization expansion ctqmc simulations. I want to have an estimation of like, if it saturates with interaction parameters and if simulation is long enough. Appreciate your help. Best Wishes Jia

3 4

Problem with ALPS homepage
by Niraj Ghimire 20 Sep '14

20 Sep '14

Dear ALPS users/developers, The "User Workshops" section given on the ALPS homepage ( http://www.comp-phys.org/lugano04/Talks.html) does not work. It just shows the list of talk but none of the items on the list open. I tried it on Mozilla Firefox and Google Chrome (in Ubuntu), didn't work. ~Niraj

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Vispython not working
by Paul Fanto 15 Sep '14

15 Sep '14

Hello, I am trying to install ALPS on a Mac OS X (version 10.7.5). I installed ALPS from binary packages, following the instructions I found on the ALPS website. I also installed the most recent version of VisTrails and the ALPS VisTrails module in order to use Python to implement simulations in ALPS. When I try to call "Vispython" in my terminal, however, I just get an error: "vispython: command not found." Could anyone explain why this is happening and how I can get Python working with ALPS? Thanks very much. Best regards, Paul Fanto Princeton University | Class of 2015 Department of Physics

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mps_optim
by Mateusz Łącki 15 Sep '14

15 Sep '14

Dear All I am trying to compute low energy eigenstates of a small L=10 system of spin-1/2 nodes using the DMRG, implemented as mps_optim to compute a ground state and a first excited state for a cetrain model (model.xml pasted below). Unfortunately what i get is two states, but the state returned as a ground state (numer „0“) as a greater energy then the excited state. More specifically I compute the state twice: using NUMBER_EIGENVALUES=1 (then the gs energy is -4) and NUMBER_EIGENVALUES=2 (then the gs energy is -4 and excited state’s energy is -5 (which is is fact the ground state’s energy). the Fulldiag code returns correct (verified by fulldiag of my own) eigenvalues. The alps-dmrg does not converge in reasonable number of sweeps. What is worse it returns energy of order of -18, so that is significantly below the ground state energy. Does the alps-dmrg support the hamiltonian that I have wrote at all? FINAL SWEEP - LAST ITERATION NUMBER OF STATES: 16 2 2 16 1024 E0 = -17.4530961018 E0 = -8.52509624929 EXCITED OVERLAP(0) = 3.07571832172e-06 E(1) = -8.52509624929 GAP(1) = -17.4530961018 -8.52509624929 8.92799985252 ITER = 4 ENTROPY = 2.62675527051 DMRG as any minimization routine is subject to „local minimum“ problem, but I have never seen it to fail so dramatically. I had the thought that the key may be the following line in the ouput: "This binary contains symmetries: nu1, " but I have set nothing like „N_total=10“. Just to be sure I have redefined „spin“ basis to a new „spinc“ from which I have removed the „constraint" metatag. TO sum up I have following issues/questions: - matter of convergence of mps_optimize - why alps-dmrg returns significantly lower energy than fulldiag on a small exemplary system? - is it some sort of constraints ? I do not want to use any conservation laws. W would like to do a brute DMRG without any good quantum numbers. Kind Regards, Mateusz Łącki Files: *********** input file taken by parameter2xml ********** MODEL_LIBRARY="/home/lacki/alpsdmrg/models.xml" LATTICE="open chain lattice" MODEL="SlonTrabalski" SWEEPS=8 NUMBER_EIGENVALUES=2 NUMSTATES=100 {L=10; V=0.1} ************* /home/lacki/alpsdmrg/models.xml ********** (I post only the modified things) <BASIS name="spinc"> <SITEBASIS ref="spin"> <PARAMETER name="local_spin" value="local_S#"/> <PARAMETER name="local_S#" value="local_S"/> <PARAMETER name="local_S" value="1/2"/> </SITEBASIS> </BASIS> <HAMILTONIAN name="SlonTrabalski"> <PARAMETER name="V" default="0"/> <BASIS ref="spinc"/> <SITETERM site="i"> V*Sx(i) </SITETERM> <BONDTERM source="i" target="j"> -(0.5)*(Splus(i)*Sminus(j)+Splus(j)*Sminus(i))-(0.5)*(Splus(i)*Splus(j)+Sminus(i)*Sminus(j)) </BONDTERM> </HAMILTONIAN>

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dmrg
by Mateusz Łącki 13 Sep '14

13 Sep '14

Dear All, I am still using alps-dmrg for my computation - mps_optim is giving me some troubles, that I will describe later in a separate email. Is is possible to ask the dmrg application to clean its temporary files after computation is done? the folder which I have specified using TEMP_DIRECTORY=/home/lacki/tmp/ is filled with old data. Of course I could write a script that checks launch date of each of „dmrg“ processes currently running and deletes all older files, but it seems really cumbersome. Kind Regards, Mateusz Łącki

2 1

memory usage in DMRG
by Mateusz Łącki 11 Sep '14

11 Sep '14

Dear All, I have been running the following input: <pasted at the bottom> I have observed that for Bose-Hubbard model on chain of length L=256, unit filled, under open boundary conditions the DMRG code uses over 32G memory (this is the hardware limit, it clearly wants more, for L=128 it was around 20G). is that normal? I would estimate that an MPS state of 256 sites, with bond dimension 60, local Hilbert space 7 should be much smaller (even if we allow for a small constant factor for temporary data) Kind Regards, Mateusz Łącki LATTICE="open chain lattice" MODEL="boson Hubbard" SWEEPS=8 Nmax=6 NUMBER_EIGENVALUES=1 L=256 CONSERVED_QUANTUMNUMBERS="N" N_total=256 VERBOSE=0 t=0.25 U=1 mu=0 {MAXSTATES=60}

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