January 2016 - Comp-phys-alps-users

Problem in running the ALPS (spinmc) code in the parallel mode aith MPI
by D´Souza, Sunil Wilfred 15 Feb '16

15 Feb '16

Dear ALPS users, I am trying to run a spinmc simulation in the parallel mode by using the command mpiexec -np 2 spinmc --mpi parm2a.in.xml --Tmin 5 On executing the command I am getting the following error messages [LIN21:20344] *** Process received signal *** [LIN21:20344] Signal: Segmentation fault (11) [LIN21:20344] Signal code: Address not mapped (1) [LIN21:20344] Failing at address: (nil) [LIN21:20344] [ 0] /lib64/libpthread.so.0(+0xf9f0) [0x7f85f73969f0] [LIN21:20344] [ 1] /opt/openmpi/1.4.5/gcc/lib64/openmpi/mca_pml_v.so(+0x1b62) [0x7f85f1359b62] [LIN21:20344] [ 2] /opt/openmpi/1.4.5/gcc/lib64/libopen-pal.so.0(mca_base_components_close+0x76) [0x7f85f66286c6] [LIN21:20344] [ 3] /opt/openmpi/1.4.5/gcc/lib64/libmpi.so.0(mca_pml_base_select+0x301) [0x7f85f6b2cd11] [LIN21:20344] [ 4] /opt/openmpi/1.4.5/gcc/lib64/libmpi.so.0(+0x39acc) [0x7f85f6aecacc] [LIN21:20344] [ 5] /opt/openmpi/1.4.5/gcc/lib64/libmpi.so.0(MPI_Init+0x16b) [0x7f85f6b0ca8b] [LIN21:20344] [ 6] /home/sunil/ALPS2.2/lib/libalps.so.2(_ZN4alps9comm_initERiRPPcb+0x58) [0x7f85f8327088] [LIN21:20344] [ 7] /home/sunil/ALPS2.2/lib/libalps.so.2(_ZN4alps9scheduler5startEiPPcRKNS0_7FactoryE+0x37) [0x7f85f85678d7] [LIN21:20344] [ 8] spinmc(main+0x15) [0x449a85] [LIN21:20344] [ 9] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f85f454bbe5] [LIN21:20344] [10] spinmc() [0x449dd5] [LIN21:20344] *** End of error message *** -------------------------------------------------------------------------- mpiexec noticed that process rank 0 with PID 20344 on node LIN21 exited on signal 11 (Segmentation fault). -------------------------------------------------------------------------- I have tried running a band structure code in the parallel mode using the mpirun and i am having no problems in running that code. but in the case of ALPS, I am encountering the above problem. I am attaching the cmake txt file for your consideration to make sure that all the fields are correct. I have crosschecked the MPI library path in cmake txt file and i find it to be alright. I am not able to figure out what exactly is causing this problem. I am kindly requesting you to provide me help in solving this issue. I thank you in advance for your time and consideration. with best regards Sunil

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a problem when i use 2 band chain lattice
by 北尘心 27 Jan '16

27 Jan '16

Dear all, I want to use 2 band chain lattice (there are three edge types in unitcell) in my hubbard model which is in lattices.xml file. I build the lattice according to guidance in the website: <LATTICES> <LATTICE name="chain lattice" dimension="1"> <PARAMETER name="a" default="1"/> <BASIS><VECTOR>a</VECTOR></BASIS> <RECIPROCALBASIS><VECTOR>2*pi/a</VECTOR></RECIPROCALBASIS> </LATTICE> <UNITCELL name="2band1d" dimension="1"> <VERTEX type="0"/> <VERTEX type="1"/> <EDGE type="0"><SOURCE vertex="1" offset="0"/><TARGET vertex="2" offset="0"/></EDGE> <EDGE type="1"><SOURCE vertex="1" offset="0"/><TARGET vertex="1" offset="1"/></EDGE> <EDGE type="2"><SOURCE vertex="2" offset="0"/><TARGET vertex="2" offset="1"/></EDGE> </UNITCELL> <LATTICEGRAPH name = "2 band chain lattice"> <FINITELATTICE> <LATTICE ref="chain lattice"/> <EXTENT dimension="1" size ="L"/> <BOUNDARY type="periodic"/> </FINITELATTICE> <UNITCELL ref="2band1d"/> </LATTICEGRAPH> </LATTICES> Because there are three edge types in unitcell , i wonder what I should do to design hopping in my model. I design two solutions ,like : <HAMILTONIAN name="boson Hubbard"> <PARAMETER name="mu" default="0"/> <PARAMETER name="t0" default="1"/> <PARAMETER name="t1" default="2"/> <PARAMETER name="t2" default="3"/> <PARAMETER name="U" default="0"/> <BASIS ref="boson"/> <SITETERM site="i"> -mu*n(i)+U*bdag(i)*bdag(i)*b(i)*b(i)/2 </SITETERM> <BONDTERM type="0" source="i" target="j"> -t0*(bdag(i)*b(j)+bdag(j)*b(i)) </BONDTERM> <BONDTERM type="1" source="i" target="j"> -t1*(bdag(i)*b(j)+bdag(j)*b(i)) </BONDTERM> <BONDTERM type="2" source="i" target="j"> -t2*(bdag(i)*b(j)+bdag(j)*b(i)) </BONDTERM> </HAMILTONIAN> and <HAMILTONIAN name="boson Hubbard"> <PARAMETER name="mu" default="0"/> <PARAMETER name="t0" default="1"/> <PARAMETER name="t1" default="2"/> <PARAMETER name="t2" default="3"/> <PARAMETER name="U" default="0"/> <BASIS ref="boson"/> <SITETERM site="i"> -mu*n(i)+U*bdag(i)*bdag(i)*b(i)*b(i)/2 </SITETERM> <BONDTERM source="i" target="j"> -t0*(bdag(i)*b(j)+bdag(j)*b(i))-t1*(bdag(i)*b(j)+bdag(j)*b(i))-t2*(bdag(i)*b(j)+bdag(j)*b(i)) </BONDTERM> </HAMILTONIAN> I want to know my two design which one is correct? Yours sincerely, Xingbo Wei Zhejiang Normal Universtiy, Jinhua, 230014, China

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sawtooth lattice
by 北尘心 27 Jan '16

27 Jan '16

Dear ALPS community, I have some problems about sawtooth lattice, which is shown in paper 'Bose condensation in flat bands (PhysRevB.82.184502)'. After having canvassed the ALPS tutorial, I construct an one-dimensional lattice with nearest-nearest neighbor hopping and next-nearest neighbor hopping, which is equivalent to the sawtooth lattice. Unfortunately, I still can't follow Fig4(b) of Phys. Rev. B 82, 184502 (2010). The job, lattices.xml and models.xml are shown as follows. I don't know what's wrong with my codes. Could you give me any suggestions ? Thank you very much ! ------------------------------------------------------------------------------------------------------------- job: LATTICE_LIBRARY="lattices.xml" MODEL_LIBRARY="models.xml" LATTICE="sawtooth open chain lattice"; MODEL="sawtooth boson Hubbard"; SWEEPS=20; MAXSTATES=200; T=0; t=1.0 t'=sqrt(2) U=1.0; MEASURE_LOCAL[n_density]=n MEASURE_CORRELATIONS[n_correlation]="n:n" CONSERVED_QUANTUMNUMBERS="N"; {L=40,N_total=20,Nmax=20;} {L=40,N_total=21,Nmax=21;} {L=40,N_total=22,Nmax=22;} {L=40,N_total=23,Nmax=23;} {L=40,N_total=24,Nmax=24;} ------------------------------------------------------------------------------------------------------------- lattice.xml: <LATTICES> <LATTICE name="chain lattice" dimension="1"> <PARAMETER name="a" default="1"/> <BASIS><VECTOR>a</VECTOR></BASIS> <RECIPROCALBASIS><VECTOR>2*pi/a</VECTOR></RECIPROCALBASIS> </LATTICE> <UNITCELL name="sawtooth" dimension="1"> <VERTEX id="1" type="0"><COORDINATE>0 </COORDINATE></VERTEX> <VERTEX id="2" type="1"><COORDINATE>0.5 </COORDINATE></VERTEX> <EDGE type="0"><SOURCE vertex="1" offset="0"/><TARGET vertex="2" offset="0"/></EDGE> <EDGE type="1"><SOURCE vertex="1" offset="0"/><TARGET vertex="1" offset="1"/></EDGE> <EDGE type="2"><SOURCE vertex="2" offset="0"/><TARGET vertex="1" offset="1"/></EDGE> </UNITCELL> <LATTICEGRAPH name = "sawtooth open chain lattice"> <FINITELATTICE> <LATTICE ref="chain lattice"/> <EXTENT dimension="1" size ="L"/> <BOUNDARY type="open"/> </FINITELATTICE> <UNITCELL ref="sawtooth"/> </LATTICEGRAPH> </LATTICES> ------------------------------------------------------------------------------------------------------------- model.xml: <SITEBASIS name="boson"> <PARAMETER name="Nmax" default="infinity"/> <QUANTUMNUMBER name="N" min="0" max="Nmax"/> <OPERATOR name="bdag" matrixelement="sqrt(N+1)"> <CHANGE quantumnumber="N" change="1"/> </OPERATOR> <OPERATOR name="b" matrixelement="sqrt(N)"> <CHANGE quantumnumber="N" change="-1"/> </OPERATOR> <OPERATOR name="n" matrixelement="N"/> </SITEBASIS> <HAMILTONIAN name="sawtooth boson Hubbard"> <PARAMETER name="t" default="1"/> <PARAMETER name="t'" default="0"/> <PARAMETER name="U" default="0"/> <BASIS ref="boson"/> <SITETERM site="i"> U*bdag(i)*bdag(i)*b(i)*b(i)/2 </SITETERM> <BONDTERM type="0" source="i" target="j"> -t'*(bdag(i)*b(j)+bdag(j)*b(i)) </BONDTERM> <BONDTERM type="1" source="i" target="j"> -t*(bdag(i)*b(j)+bdag(j)*b(i)) </BONDTERM> <BONDTERM type="2" source="i" target="j"> -t'*(bdag(i)*b(j)+bdag(j)*b(i)) </BONDTERM> </HAMILTONIAN> ------------------------------------------------------------------------------------------------------------- Best regards, Xiaofan Zhou

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Negative Truncation error calculated by DMRG algorithm
by T.J.Hewitt 25 Jan '16

25 Jan '16

Dear ALPS users, I've been using the DMRG algorithm provided by ALPS to calculate energies and spin gaps for simple quantum systems. I've noticed that the value calculated for the truncation error comes out to be negative for some of the iterations. These specific instances have very small values, typically 10^-16, 10^-17 and 10^-18. My understanding of the truncation error is that it is the sum of the probabilities of the truncated states, thus always producing a positive value. So I'm not sure how a negative truncation error is occurring. It seems to occur on any DMRG program I run, even the simple ones provided in the DMRG tutorials. Perhaps it is a quirk of the algorithm or how the computer is handling some rounding. I found message on the mailing list archives about this exact question but it was never answered. I've attached some output data. I used the program 'spin_one_half.py' straight from the first DMRG tutorial here<http://alps.comp-phys.org/mediawiki/index.php/ALPS_2_Tutorials:DMRG-01_DMRG>, unmodified, to produce the provided output. Any insight and advice is much appreciated. Thanks. Regards, Tyler

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A Few Questions about the DMRG code.
by T.J.Hewitt 13 Jan '16

13 Jan '16

Dear All, I'm currently using the ALPS DMRG algorithm to calculate energy eigenvalues for a given quantum model. After running many simulations and analyzing the results I have a few questions that I'm hoping you can answer. 1) The lattice model I'm looking at is an open ladder with 2-legs. Is the DMRG code supplied in ALPS capable of correctly handling such a lattice configuration? 2) I've also noticed that the results from these DMRG simulations are non-deterministic, that is the result is only consistent to a specific decimal point every run, given the same input parameters. Other DMRG programs I have used previously gave deterministic results given the same input parameters. I'm assuming that the inconsistency of the ALPS DMRG results is due to the utilization of the Lanczos algorithm to calculate the energy eigensets on each run. Can someone confirm that this is the case? Additionally, I have tried changing the 'LANCZOS_TOLERANCE' parameter, which I'm assuming would give better and more consistent results, but this has no effect on the results. Given that my assumption is correct what is the proper way to code this input parameter. Thanks, Tyler Hewitt

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measure correlatons use mps codes
by 北尘心 06 Jan '16

06 Jan '16

Hi, I want to measure corrections by mps code.I use the command like MEASURE_HALF_NN_CORRELATIONS[A]="cdag_up:cdag_down:c_up:c_down". but it unable to calculate the following situtation: "cdag_up:cdag_down:c_up:c_down|(0,1,1,2)".How can i acheieve it? Thank you very much if you could give me any advice . Best, Xinbo Wei

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ALPS DWA - Moving to C++11/ 14
by Tama Ma - Yotcopi 06 Jan '16

06 Jan '16

Dear ALPS community, Is there anyone who is strongly against using C++11/ 14 for ALPS DWA development? Also, if you have any desirable requirements from the physic community, please kindly drop me your comments here. Thank you very much. Best regards, Tama MA

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