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

Re: [ALPS-users] Electron-lattice using ALPS
by Matthias Troyer 25 Dec '07

25 Dec '07

Hi Sarosh Ali, please send your questions to the ALPS user list instead of personay to me. You'll get much faster answers that way. On 24 Dec 2007, at 13:36, sarosh ali wrote: > I am a student of IIT Kharagpur. I am attempting to numerically > solve a exciton-lattice system. I tried to use ALPS, using the spin- > less fermion basis with various terms in the hamiltonian defined. I > tried to do full-diagonalization for 3 sites chain. However, either > our computers hung or I got errors like "cannot get quantumnumber". > Probably, we have not set up ALPS properly or the system > configuration here is too low. Maybe your input files have problems. Can you post the files you use and we can try to help. > So, in order to solve the problem, I intend to write a C code myself > for arbitrary number of sites on a chain. I do have a matrix > diagonalization code. Could you please provide me with an algorithm > for how to order the basis elements and how to label them. My basis > is a lattice basis for two bands with electrons in the conduction > band and holes in the valence band is as follows: | n1,n2,n3....> X | > m1,m2,m3.....> , where ni indicates the number of electrons and mi > the number of holes at the lattice site i. I donot want to trouble > you with my problem. However, if you could provide me with a generic > way to generate basis, it would be a great help. Sorry, I just don't have the time to explain to you how to write a complete exact diagonalization code from scratch - since this is essentially what you ask here. > P.S: I have another question not related to this. How to use Alps > for quasi-particles? What do you mean by quasi-particles? What is your model? Matthias Troyer

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Lattice Definitions
by Niall Moran 13 Dec '07

13 Dec '07

Hi, I am trying to understand how lattices are defined in ALPS and am having some difficulties. For example the hexagonal lattice from the lattices.xml that comes with ALPS (1.3b6) has dimension 2 but then the basis vectors and reciprocal basis vectors are 3 dimensional. <LATTICE name="hexagonal lattice" dimension="2"> <PARAMETER name="a" default="1"/> <PARAMETER name="c" default="1"/> <BASIS> <VECTOR>a 0 0</VECTOR> <VECTOR>a/2 a*sqrt(3)/2 0</VECTOR> <VECTOR>0 0 c</VECTOR> </BASIS> <RECIPROCALBASIS> <VECTOR>2*pi/a -2*pi/a/sqrt(3) 0 </VECTOR> <VECTOR>0 4*pi/a/sqrt(3) 0 </VECTOR> <VECTOR>0 0 2*pi/c</VECTOR> </RECIPROCALBASIS> </LATTICE> Maybe I'm not getting how a lattice can be defined by basis vectors. Are there any good resources online about this? I have looked at the ALPS wiki but the images are missing from the pages about lattice definitions. Also how can one specify the extent in each direction and the boundary conditions for the above lattice? Also how will the vertices be numbered? Any help is much appreciated. Kind Regards, Niall.

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DMRG question
by Justin David Peel 11 Dec '07

11 Dec '07

Hi all, I just have a quick question. How can I get the dmrg program to output the max truncation error during the final sweep (or any truncation error for that matter) to the output file? I know that it is output to the screen, but I would like it in the output file. Thanks, Justin

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extractxmgr on Ubuntu Gutsy Gibbon
by MICHEL Laurent 11 Dec '07

11 Dec '07

Hi, I posted the question below a few days ago, but I don't know if somebody can help me ... ??? Regards, L. Hi, I am new on ALPS and I don't know where to find support for the following problem : I am making some simulations using the ALPS libraries, and, at the end, when I want to use extractxmgr, if I type something like zadigus@ubuntu:~/apps/dyqm-1.0/tutorial/tebd$ bash extractxmgr ../xml/plot.sz.xml neel1a.task1.eval0.xml neel1a.task1.eval1.xml I get the following error : test: 28: ==: unexpected operator tail: Warning: "+number" syntax is deprecated, please use "-n +number" tail: Warning: "+number" syntax is deprecated, please use "-n +number" test: 28: ==: unexpected operator test: 28: ==: unexpected operator /tmp/plot26738:2: parser error : Opening and ending tag mismatch: meta line 2 and head <head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head> ^ /tmp/plot26738:4: parser error : Opening and ending tag mismatch: head line 2 and html </html> ^ /tmp/plot26738:5: parser error : Premature end of data in tag html line 1 ^ cannot parse /tmp/plot26738 What can I do for this to work ? I have the latest updated version of Ubuntu (7.10) and I am working now with the ALPS library provided by Ubuntu. I first tried with the beta version which can found on your website (alps-1.3b6), but the problem is exactly the same. Best regards, L. -- MICHEL Laurent Physicien presque accompli www.cjcaesar.ch/ Petits-Quartiers 4 1680 ROMONT laurent.michel(a)unifr.ch

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Summer School
by Matthias Troyer 10 Dec '07

10 Dec '07

Dear ALPS developers and users I would like to draw your attention to the 2008 International Summer School "Numerical Methods for Correlated Systems in Condensed Matter". The School will be held over an intensive two-week period May 25 to June 6, 2008 in Sherbrooke. It will hold to the high standards of the Les Houches and Boulder Schools. This 45 hours PhD level School is aimed at advanced graduate students, postdocs and Faculty. In addition to formal lectures by renowned speakers, it includes hands-on training on freely available software packages for both ab-initio methods and for model Hamiltonians of interacting systems. There is no registration fee. Room and board will be 1000 CAD for single occupancy and 750 CAD for double occupancy (1 CAD ~ 1 USD). Students can register for transferable PhD level course credit with Universit? de Sherbrooke. For more details on the list of speakers and registration, please consult http://pitp.physics.ubc.ca/confs/sherbrooke/index.html Sincerely yours, Andre'-Marie Tremblay Massimo Boninsegni Michel Cote David Senechal Matthias Troyer

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extractxmgr on Ubuntu Gutsy Gibbon
by MICHEL Laurent 05 Dec '07

05 Dec '07

Hi, I am new on ALPS and I don't know where to find support for the following problem : I am making some simulations using the ALPS libraries, and, at the end, when I want to use extractxmgr, if I type something like zadigus@ubuntu:~/apps/dyqm-1.0/tutorial/tebd$ bash extractxmgr ../xml/plot.sz.xml neel1a.task1.eval0.xml neel1a.task1.eval1.xml I get the following error : test: 28: ==: unexpected operator tail: Warning: "+number" syntax is deprecated, please use "-n +number" tail: Warning: "+number" syntax is deprecated, please use "-n +number" test: 28: ==: unexpected operator test: 28: ==: unexpected operator /tmp/plot26738:2: parser error : Opening and ending tag mismatch: meta line 2 and head <head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head> ^ /tmp/plot26738:4: parser error : Opening and ending tag mismatch: head line 2 and html </html> ^ /tmp/plot26738:5: parser error : Premature end of data in tag html line 1 ^ cannot parse /tmp/plot26738 What can I do for this to work ? I have the latest updated version of Ubuntu (7.10) and I am working now with the ALPS library provided by Ubuntu. I first tried with the beta version which can found on your website (alps-1.3b6), but the problem is exactly the same. Best regards, L. -- MICHEL Laurent Physicien presque accompli www.cjcaesar.ch/ Petits-Quartiers 4 1680 ROMONT laurent.michel(a)unifr.ch

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staggered magnetization: special definition of a bipartite lattice necessary?
by Björn Vogt 26 Nov '07

26 Nov '07

Hello, I am interested in using ALPS for Heisenberg systems including higher order on-site-anisotropies. To measure the staggered magnetization in an antiferromagnetic model: Do I have to define a special bipartite lattice or do the usual lattices in lattices.xml work? Yours, Björn Vogt -- Björn Vogt I. Institut für Theoretische Physik Universität Hamburg Jungiusstr. 9 Raum 122 040/42838-2056 http://www.physnet.uni-hamburg.de/hp/bvogt ____________________________________________________ This mail was sent through PHYSnet-WebMailer http://www.PHYSnet.uni-hamburg.de/mail

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1D open chains with "defects"
by Cristian Degli Esposti Boschi 16 Nov '07

16 Nov '07

I would like to use ALPS to study a spin model defined on an open chain in which one or two sites in the middle of the chain can host "defects", for istance the local magnetic field and/or the exchange with neighbouring sites are different from all the other interactions in the chains. Can it be done by proper definitions in the lattice.xml file? (and of course then also in models.xml) Thanks a lot for your work. Cheers, Cristian -- ___________________________________________________ Cristian Degli Esposti Boschi CNR, CNISM, Unita' di Ricerca di Bologna, c/o Dipartimento di Fisica, Universita' di Bologna viale Berti-Pichat, 6/2, 40127, Bologna, Italia tel. ++39 051 2095114 fax ++39 051 2095113 e-mail: cristian.degliesposti -AT- unibo.it web: http://www.df.unibo.it/ricerca-01/theory ___________________________________________________

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Magnetization histogram from exact diagonalization?
by Austen Lamacraft 07 Nov '07

07 Nov '07

Hello, Is there a simple way to get at the histogram of the distribution of the magnetization in the ground state of (say) the transverse field Ising model? Or failing that, a way to get out the full ground state eigenvector obtained by exact diagonalization? A related question: Is there a simple way to take the expectation value of an arbitrary function of spin at a single site in Monte Carlo? I guess this comes under "Definition of custom measurements", and that tutorial isn't finished yet. Thanks, Austen

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dmrg tutorial example is not running
by Aniket Kulkarni 03 Nov '07

03 Nov '07

Hi all, I am trying to run dmrg tutorial example but it is showing error. The error is as follows: $ simple_dmrg <parm1 error: ALPS noninteractiong DMRG application version 1.0 available from http://alps.comp-phys.org/ copyright (c) 2003-2004 by Salvatore R. Manmana <Salva(a)theo3.physik.uni-stuttg art.de> Reinhard M. Noack <Reinhard.Noack(a)physik.uni-marbur g.de> Ian McCulloch <ianmcc(a)physik.rwth-aachen.de> for details see the publication: F. Alet et al., Report cond-mat/0410407. EXCEPTION: bad lexical cast: source type value could not be interpreted as target t Please see the error and tell me the problem. Thanks in advance with regards, Aniket

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