August 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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[ALPS] Randomized parameter per site
by John Ian Kenneth E. Felismino 05 Sep '17

05 Sep '17

Hi! Is it possible to have a site-dependent random parameter using DMRG in ALPS? For example in every a different random value for the Magnetic Field Strength acting on the model is assigned to each site. Thanks, Ian Felismino

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Total particle number can not be conserved using ALPS TEBD simulation
by Sun Rongyang 02 Sep '17

02 Sep '17

Dear ALPS users, When I follow the ALPS TEBD tutorial about hard-core boson model(http://alps.comp-phys.org/mediawiki/index.php/ALPS_2_Tutorials:TEBD-0… by Python, I measured the average particle number for each site, i.e. 'Avg Number' except the 'Loschmidt Echo' and 'V' by the following python code: data = pyalps.load.loadTimeEvolution(pyalps.getResultFiles(prefix='1D_HardcoreBosonModel'), measurements=['Loschmidt Echo', 'V', 'Avg Number']) Then I found the 'Avg Number' equals 0.3! This means that the total particle number is 0.3*10=3, not 5. In the tutorial, the conserved quantum number is 'N_total': 5. When I change the 'N_total' to 1 and 10, I got the same 'Avg Number'=0.3 Can any one give me some help? Thanks a lot! Best regards, Rongyang Sun ----------------------------------------------------------------- Rongyang Sun Ph.D. Candidate Theoretical Quantum Matter Physics Institute for Advanced Study, Tsinghua University, Beijing 100084, China E-mail: sunry15(a)mails.tsinghua.edu.cn; sun-rongyang(a)outlook.com

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staggered susceptibility
by Stanislaw Galeski 23 Aug '17

23 Aug '17

Dear All, I am trying to calculate the staggered susceptibility of a Heisenberg spin ladder in a magnetic field, however the results I am got seem a bit disturbing. Thus my question: in the dirloop_sse package does the staggered susceptibility mean a staggered response to a staggered field of a staggered response to a uniform field? Unfortunately I could not find the answer in the wiki. Thanks for help! Stanislaw _____ Stanislaw Galeski ETH Zurich Laboratory for Solid State Physics HPF F 15 Otto-Stern-Weg 1 CH-8093 Zurich Switzerland

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Question about installing ALPS through anaconda
by Yi-Ping Huang 19 Aug '17

19 Aug '17

Hi, I try to use $conda install -c conda-forge alps to install ALPS using the most updated anaconda package. However, I got the error message suggesting some dependency issue. UnsatisfiableError: The following specifications were found to be in conflict: - alps - navigator-updater Use "conda info <package>" to see the dependencies for each package. As I try to use conda info navigator-updater to check what is happening, it somehow suggest navigator-updater 0.1 is build using python 3.6. Is it why I get the dependency issue? If so, can I still using anaconda to install ALPS? or I need to build it from the source files? Thanks a lot. Yi-Ping

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[ALPS} Using nvblas to boost calculations
by John Ian Kenneth E. Felismino 19 Aug '17

19 Aug '17

Greetings! I was wondering if it is possible to add nvblas from cuda 8.0 when building alps to boost the speed of the calculations. This possible increase in speed and efficiency will help a lot to me and my colleagues who have share computing resources in the laboratory. Thanks, Ian Felismino

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Can the mps_optim calculate the entanglement spectrum of the lattice with two cuts ?
by X****** **** 19 Aug '17

19 Aug '17

Dear all, Can the mps_optim calculate the entanglement spectrum of the lattice with two cut ? For instance, the lattice is separated to A B C, how to calculate the -Ln(\rho_B), \rho_B=Tr_{A,C} |\Phi><\Phi|. Thanks, Xiaofan Zhou

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Problem on finding xsl path
by Jin Hyoun Kang 19 Aug '17

19 Aug '17

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Re: [ALPS-users] [ALPS} Using nvblas to boost calculations
by John Ian Kenneth E. Felismino 18 Aug '17

18 Aug '17

We wanted to use nvblas to intercept any level 3 blas operations. My colleagues and I are mainly using mps-optim for dmrg applications. Thanks, Ian Felismino On Aug 18, 2017 12:02 AM, "Matthias Troyer" <troyer(a)phys.ethz.ch> wrote: Which calculations do you want to boost that way? > On 17 Aug 2017, at 01:03, John Ian Kenneth E. Felismino < jfelismino(a)nip.upd.edu.ph> wrote: > > Greetings! > > I was wondering if it is possible to add nvblas from cuda 8.0 when building alps to boost the speed of the calculations. This possible increase in speed and efficiency will help a lot to me and my colleagues who have share computing resources in the laboratory. > > Thanks, > Ian Felismino > > > ---- > 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. ---- 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.

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mps_optim can not calculate 1D Kitaev chain
by Xiaofan Zhou 09 Aug '17

09 Aug '17

Dear all, I write some files to calculate 1D Kitaev chain. However, it dose not work. All files are attached. The HAMILTONIAN contain the code: -t#*(cdag(i)*c(j)+cdag(j)*c(i)-c(i)*c(j)-cdag(j)*cdag(i)) . Best, Xiaofan Zhou 2017-08-08

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