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1244 discussions

Results is different for worm(sse) and wolfram mathematica
by vitbka konef 22 Nov '14

22 Nov '14

First , I was obtained density of magnetization and density of energy curves of isotropic Heisenberg model on square lattice (2x2) using worm and dirloop_sse. After I was obtained these curves with wolfram mathematica. Curves for magnetization density(density of energy) obtained with mathematica and worm(sse) is strongly differ one from another.They must match. I was attached the files of mathematica and Heis2x2.py.

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total acceptance rate
by tesfaye mamuye 20 Nov '14

20 Nov '14

Dear ALPS developers and users I'm using CT-HYB impurity solver for single site DMFT problem. While i was simulating single site single-orbital dmft problem using CT-HYB the value of total acceptance rate negative. Is this negative value of total acceptance rate possibly accepted ?what is this negative value of total acceptance rate mean ? Tesfaye MamuyeAddis Ababa University, Ethiopia

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Anisotropic XY model in transverse magnetic field
by Олеся Крупніцька 17 Nov '14

17 Nov '14

Dear ALPS team, I want to inform you that I have found my mistake in extracting results for magnetization of anisotropic XY model on frustrated diamond spin chain in transverse magnetic field. Best regards, Olesia Krupnitska

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Anisotropic XY model in transverse magnetic field
by Олеся Крупніцька 13 Nov '14

13 Nov '14

Dear ALPS team, I am trying to obtain magnetization curve of anisotropic XY model on frustrated diamond spin chain in transverse magnetic field (m^x) using full diagonalization. For this purpose I have prepared such input file for delta=1.5; LATTICE="lattice_diamond" MODEL="spin" LATTICE_LIBRARY="lattice-diamond.xml" local_S=1/2 Jxy1 = 0.85 Jxy2 = 3.0 Jxy3 = 1.15 Jz1 = 1.275 Jz2 = 4.5 Jz3 = 1.725 L = 2 T = 0.001 {Gamma =4;} {Gamma =4.05;} {Gamma =4.1;} {Gamma =4.15;} {Gamma =4.2;} {Gamma =4.25;} {Gamma =4.3;} {Gamma =4.35;} {Gamma =4.4;} {Gamma =4.45;} {Gamma =4.5;} {Gamma =4.55;} {Gamma =4.6;} {Gamma =4.65;} {Gamma =4.7;} {Gamma =4.75;} {Gamma =4.8;} {Gamma =4.85;} {Gamma =4.9;} {Gamma =4.95;} {Gamma =5;} {Gamma =5.05;} {Gamma =5.1;} {Gamma =5.15;} {Gamma =5.2;} {Gamma =5.25;} {Gamma =5.3;} {Gamma =5.35;} {Gamma =5.4;} {Gamma =5.45;} {Gamma =5.5;} {Gamma =5.55;} {Gamma =5.6;} {Gamma =5.65;} {Gamma =5.7;} {Gamma =5.75;} {Gamma =5.8;} {Gamma =5.85;} {Gamma =5.9;} {Gamma =5.95;} {Gamma =6;} lattice-diamond.xml is: <LATTICES> <LATTICEGRAPH name="lattice_diamond"> <FINITELATTICE> <LATTICE dimension="1"> <BASIS> <VECTOR>1</VECTOR> </BASIS> </LATTICE> <PARAMETER name="L"/> <EXTENT size="L"/> <BOUNDARY type="periodic"/> </FINITELATTICE> <UNITCELL dimension="1" vertices="3"> <VERTEX id="1" type="0"> </VERTEX> <VERTEX id="2" type="0"> </VERTEX> <VERTEX id="3" type="0"> </VERTEX> <EDGE type="2"> <SOURCE vertex="1"/> <TARGET vertex="2"/> </EDGE> <EDGE type="3"> <SOURCE vertex="1"/> <TARGET vertex="3"/> </EDGE> <EDGE type="1"> <SOURCE vertex="2"/> <TARGET vertex="3"/> </EDGE> <EDGE type="3"> <SOURCE vertex="3"/> <TARGET vertex="2" offset="1"/> </EDGE> <EDGE type="1"> <SOURCE vertex="3"/> <TARGET vertex="1" offset="1"/> </EDGE> </UNITCELL> </LATTICEGRAPH> </LATTICES> It works perfect for L=2 (6 sites), but I cant obtain correct magnetization curve for L=3 (9 sites) or L= 4 (12 sites) etc. Would you be so kind to explain me why it works well for small chain and worse for slightly larger chain? Best regards, Olesia Krupnitska

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correlation function and alternating chain
by Jalal Jahangiri 01 Nov '14

01 Nov '14

Hello Dear ALPs users I have 2 questions.I am novice in ALPS. 1- I want to calculate correlation function for coupled ladders. my input file is attached in the output file, there are 4 values of correlation function for nearest neighbors. this is part of output file *Spin Correlations*[( 0,0 ) -- ( 0,1 )]*Spin Correlations*[( 0,0 ) -- ( 0,1 )]*Spin Correlations*[( 0,0 ) -- ( 0,1 )]*Spin Correlations*[( 0,0 ) -- ( 0,1 )] -whereas i expect there is one of them or at least 3 of them (x-y-z), is there a bug in the input file or something else? 2- How do I define an alternating chain? (my mean is alternating coupling constants) Best Regards

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cluster algorithm for classical spin models
by Rachele Nerattini 22 Oct '14

22 Oct '14

Dear ALPS community, I am writing for a question on the algorithm for classical Monte Carlo simulation of spin models. From the simulations I performed on classical O(2), O(3) and O(4) models it turned out that the autocorrelation time is quite large, let's say of about 80 o 90, for the energy density observable. I just would like to understand better if there is a particular reason for such a big tau and which kind of algorithm is really used for the simulation: Swendsen-Wang , Wolff single cluster or even something else? This is also because the term ”sweep” is quite unusual when cluster algorithms are concerned. I really thank you all for your help. Best regards, Rachele Nerattini -- --------------------------------------------------------------------------------------------- Rachele Nerattini Dip. di Fisica e Astronomia, Università di Firenze Via G. Sansone, 1, 50019 Sesto Fiorentino (FI), Italy ---------------------------------------------------------------------------------------------

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query regarding double counting in classical monte carlo simulation
by D´Souza, Sunil Wilfred 22 Oct '14

22 Oct '14

Dear Alps Users, I am trying to simulate a binary ferromagnetic system i.e FeCo. I am running the classical monte carlo simulations by using the classical Heisenberg model . I am using the spinmc binary for my task. My confusion is regarding the double counting aspect of the Heisenberg model. since i have FeCo as the binary system. I will have two set of edges , which are as follows: Set 1 : { Fe-Fe, Fe-Co, Co-Co} Set 2 : {Fe-Fe, Fe-Co, Co-Fe, Co-Co}. My question is, In order to simulate the FeCo system correctly should i consider the edge Fe-Co ( J= 25 meV) only once OR should i consider both F e-Co and Co-Fe (J= 50 mev). I have tried to locate the exact equation of the Heisenberg Hamiltonian which is being used for the classical monte carlo simulation, but unfortunately i could not find this information. is the double counting aspect already taken care in the ALPS simulations. if so, then i think i have to define both Fe-Co and Co-Fe edges for the simulation. I am kindly requesting you to provide me insight into this aspect. I am caught up with this confusion, which is stopping me from proceeding further. Therefore, I am kindly requesting you to provide me your suggestions and help regarding the above mentioned issue. I thank you in advance for your kind consideration and time. with best regards Sunil

2 1

dwa & Heisenberg chain
by Rene John Kerkdyk 22 Oct '14

22 Oct '14

Dear ALPS developers and users, while using the dwa application I stumbled upon a segmentation fault. This happens when I try to simulate a S=1/2 Heisenberg chain. Below is the input file "dwa.parm" used and the output generated by ALPS. Is it not possible to calculate this spin model with the dwa application? Best, René Reference: I am using the alps-2.2.b3-r7462-src to build ALPS and work on the following operating system: Linux version 2.6.32-431.20.5.el6.x86_64 (mockbuild(a)c6b8.bsys.dev.centos.org) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-4) (GCC) ) #1 SMP Fri Jul 25 08:34:44 UTC 2014 CentOS release 6.5 (Final) Kernel \r on an \m Input & Output: -bash-4.1$ cat dwa.parm LATTICE="chain lattice"; MODEL="spin"; LATTICE_LIBRARY="./lattices.xml" MODEL_LIBRARY="./models.xml" local_S = 1/2 J = 1 h=0 L=4; T = 0.001; SWEEPS=5000000; THERMALIZATION=100000; SKIP=500; MEASURE[Winding Number]=1 { t=0.01; } -bash-4.1$ parameter2xml dwa.parm Converting parameter file dwa.parm to dwa.parm.in.xml -bash-4.1$ dwa --write-xml dwa.parm.in.xml /***************************************************************************** /SNIP/ *****************************************************************************/ using the ALPS parallelizing scheduler copyright (c) 1994-2006 by Matthias Troyer <troyer(a)comp-phys.org>. see Lecture Notes in Computer Science, Vol. 1505, p. 191 (1998). based on the ALPS libraries version 2.2.b3 available from http://alps.comp-phys.org/ copyright (c) 1994-2013 by the ALPS collaboration. Consult the web page for license details. For details see the publication: B. Bauer et al., J. Stat. Mech. (2011) P05001. parsing task files ... Initialization stage 1 (Site states) ... starting ... finished. Initialization stage 2 (Hamiltonian) ... starting i. State minimum/maximum ... starting ... done. i. Onsite matrix ... starting a. Step 1: partial evaluate everything up to x,y,z terms ... starting ... done. b. Step 2: Initialize onsite matrix ... starting: ... done. ... done. iii. Bond strength matrix ... starting ... done. ... finished. Initialization stage 3 (Lookups) ... starting ... finished. Initialization stage 4 (Measurements) ... starting ... finished. Parameters ========== LATTICE = "chain lattice"; MODEL = spin; LATTICE_LIBRARY = ./lattices.xml; MODEL_LIBRARY = ./models.xml; local_S = 1/2; J = 1; h = 0; L = 4; T = 0.001; SWEEPS = 5000000; THERMALIZATION = 100000; SKIP = 500; MEASURE[Winding Number] = 1; t = 0.01; SEED = 856848597; Simulation ========== Sweeps : 5000000 Thermalization sweeps : 100000 Skip (Sweeps per measurement) : 500 Sweep counter : 0 Sweep failure counter : 0 Propagation counter : 0 Propagation failure counter : 0 Interested in time-of-flight images : 0 Waist correction : 0 Lattice ======= Name : chain lattice Dimension : 1 Total Sites/Bonds : 4 / 4 Periodic : 1 Model ===== Name : spin Charge model : 0 Spin model : 1 Site Basis : spin states : -0.5 0.5 Measurements ============ MEASURE : 1 MEASURE[Simulation Speed] : 1 MEASURE[Total Particle Number^2] : 0 MEASURE[Energy^2] : 0 MEASURE[Density^2] : 0 MEASURE[Energy Density^2] : 0 MEASURE[Winding Number] : 1 MEASURE[Local Kink:Number] : 0 MEASURE[Local Density] : 0 MEASURE[Local Density^2] : 0 MEASURE[Green Function] : 0 Created run 1 locally Starting task 1. Segmentation fault --------------------------------- René John Kerkdyk Institute for Theoretical Physics University of Goettingen Friedrich-Hund-Platz 1 D-37077 Goettingen Germany Office: A4.126 Phone: +49 551 39 7687

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mps_optim checkpointing
by Mateusz Łącki 20 Oct '14

20 Oct '14

Dear All, I would like to answer to my own question. I have found that chkp_each works also for mps_optim (not only for mps_evolve) It enables to checkpoint every few iterations (for example every 100). BTW setting chkp_each to 0 causes „division by zero“ error due to line 113 of a file: ./applications/dmrg/mps/mps_optim/dmrg_sim.hpp 113 if (stopped || (sweep+1) % chkp_each == 0 || (sweep+1) == parms["nsweeps“]) It also shows that turning off checkpointing altogether is not possible, but this is the line which has to be modified to switch it off. Kind Regards, Mateusz Łącki

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mps_optim checkpoints
by Mateusz Łącki 19 Oct '14

19 Oct '14

Dear All I would like to ask about checkpointing in mps_optim. Is it possible to turn off checkpointing in mps_optim altogether? I am doing computations on a network drive with volatile file system. I would like to limit write operations to increase reliability. Is it possible without ingeration in source code? It would also help to save a little bit of disk space... Kind Regards, Mateusz Łącki

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Comp-phys-alps-users