May 2017 - Comp-phys-alps-users - lists.phys.ethz.ch

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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import pyalps.cthyb ImportError: No module named cthyb
by Petar Bakalov 30 May '17

30 May '17

Hello, I've been using ALPS for a while (mostly the CT-HYB solver). Now we are trying to compile ALPS from source on a larger (Red Hat) cluster and we've encountered an issue. The installation proceeds mostly fine (except that test 137 python_mcanalyze fails at "make test"), but the cthyb module is missing from pyalps. i.e.: import pyalps works, but import pyalps.cthyb produces ImportError: No module named cthyb We also noticed that the hybridization binary is missing from install/bin The same installation protocol worked on another machine, so we are somewhat mystified. Where could the problem be? We are using ALPS version 2.2.0b4 alps-2.2.b4-src-with-boost.tar.gz <http://alps.comp-phys.org/static/software/releases/alps-2.2.b4-src-with-boo…> and basically follow the instructions here: http://alps.comp-phys.org/mediawiki/index.php/Building_ALPS_from_source#Bui… Best regards, Petar

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correlation functions using bond operators
by Robertson Esperanza 23 May '17

23 May '17

Hello, Thanks for all the previous help. What I've done so far is measuring correlation functions using site opertors, now I'm dealing with bond operators. For mps_optim, it seems that i can only measure correlations between single-term bond operators. For example: op1 = c_dagup(x)* c_up(y) op2 = c_dagdown(x)*c_down(y) and I can do MEASURE_HALF_CORRELATIONS['op_corr'] = op1:op2. From the results, it seems that it returns x = [i, i+1, j, j+1], y = some value I am dealing with a 10 site chain, but i only got results (for i=0) j= 2,...,8. How can i calculate the same correlation functions for j = 0, 1, and 9? Regards, Robbie

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Re: [ALPS-users] execution time of example/parapack/exchange
by Synge Todo 17 May '17

17 May '17

Dear Dominik, The parapack scheduler supports parallel workers. You can run the exchange worker in parallel by using multiple threads or processes provided that 1. the parameters are given by XML files instead of the standard input, and (running with standard input is for debugging or testing) 2. multiple threads are assigned to each worker by using -p (--threads-per-clone) option (default is -p 1). Please try, e.g., $ parameter2xml exchange.ip $ mpirun -np 4 ./exchange --mpi --threads-per-clone 4 exchange.ip.in.xml Best, Synge > From: Dominik Schildknecht <dominik.schildknecht(a)psi.ch> > Subject: [ALPS-users] execution time of example/parapack/exchange > Date: 16 May 2017 at 01:48:28 GMT-7 > To: <comp-phys-alps-users(a)lists.phys.ethz.ch> > Reply-To: comp-phys-alps-users(a)lists.phys.ethz.ch > > Dear all, > > I was testing your example in example/parapack/exchange with the > exchange.ip modified to only test the ising case, however with more > sweeps, to test the time spent. > > I know that the parallel_exchange_worker gets called (visible via the > line "EXMC: number of replicas on each process = 2 2", which will only > be outputted by the parallel_exchange_worker). I would by this output > assume that different replicas get distributed over the cores,. > > The time spent in the simulation however stays the same irrespective of > the number of processes I provide to MPI or not even call the MPI > library at all. > > I call the function in the following way: > > mpirun -np 2 ./exchange --mpi < exchange.ip > > resp. > > ./exchange < exchange.ip > > Do I miss an important argument in the input file / command line > argument, that prevents the parallel execution of replicas? > > Best, > Dominik > > -- > Paul Scherrer Institut > Dominik Schildknecht > PhD Student > WHGA/129 > CH-5232 Villigen-PSI > Phone: +41 56 310 55 68 > > > > > ---- > 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(a)lists.phys.ethz.ch. >

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execution time of example/parapack/exchange
by Dominik Schildknecht 16 May '17

16 May '17

Dear all, I was testing your example in example/parapack/exchange with the exchange.ip modified to only test the ising case, however with more sweeps, to test the time spent. I know that the parallel_exchange_worker gets called (visible via the line "EXMC: number of replicas on each process = 2 2", which will only be outputted by the parallel_exchange_worker). I would by this output assume that different replicas get distributed over the cores,. The time spent in the simulation however stays the same irrespective of the number of processes I provide to MPI or not even call the MPI library at all. I call the function in the following way: mpirun -np 2 ./exchange --mpi < exchange.ip resp. ./exchange < exchange.ip Do I miss an important argument in the input file / command line argument, that prevents the parallel execution of replicas? Best, Dominik -- Paul Scherrer Institut Dominik Schildknecht PhD Student WHGA/129 CH-5232 Villigen-PSI Phone: +41 56 310 55 68

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Long-range electrostatic interactions - Ewald Summation
by McMahon, Andrew P 14 May '17

14 May '17

Hi all, Forgive previous email, have now installed the ALPS package and I have tutorials etc running. I am trying to develop a classical Monte Carlo simulation with long range dipole-dipole interactions, the energy of which will be calculated through an Ewald summation - does anyone have any advice on how best to approach this through ALPS (I don't want to reinvent the wheel if there is already a way to do it in the package)? I suppose I can just create my own classes and energy methods in a similar fashion to this example http://alps.comp-phys.org/mediawiki/index.php/Tutorials:Code-01_Python, where the developer defines the energy update, is this how you would recommend I do it? I'm trying to think of the most efficient way from a development point of view. Thanks all, great package by the way, Andy McMahon. ----------------------------------------------- Andrew P. McMahon Theory and Simulation of Materials Imperial College London andrew.mcmahon13(a)imperial.ac.uk ------------------------------------------------

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Parameter2xml
by McMahon, Andrew P 14 May '17

14 May '17

Hi all, I've just downloaded and installed the ALPScore library and am now starting to work through some examples and tutorials. I cannot find or use the parameter2xml tool for converting a parameter file to xml on the command line, should this have come with the installation tarball or is it a tool I get from somewhere else? Any help you can offer would be greatly appreciated. Thanks, Andy McMahon. ----------------------------------------------- Andrew P. McMahon Theory and Simulation of Materials Imperial College London andrew.mcmahon13(a)imperial.ac.uk ------------------------------------------------

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DMRG measurements of observables with support only on some lattice sites
by Axel Gagge 11 May '17

11 May '17

Hello all, I am working with DMRG for a model where the unit cell consists of two lattice sites of different types (one is a boson mode while the other is a two-level/spin 1/2). Now, I want to measure say the expectation value <Sz> of my ground state on all the spin sites - how can I do this in ALPS? If I use MEASURE_LOCAL, ALPS tries to compute the expectation value of Sz for the boson sites and crashes. MEASURE_LOCAL_AT seems like the reasonable thing to work with, but does it also work for expectation values? Best regards, Axel

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