November 2006 - Comp-phys-alps-users

Plot file problems
by Austen Lamacraft 06 Dec '06

06 Dec '06

An elementary question from a beginner user... I can't get the simplest plot file examples given in the ToolsHOWTO or Tutorial:ClassicalMCSimulations to work. While extracttext, extractxmgr and direct evaluation using xsltproc all work without complaining , no points are extracted e.g. from the task files produced by the one-dimensional Heisenberg simulation in Tutorial:ClassicalMCSimulations. Thus although the plots produced by extractxmgr plot.xml parm2a.task*.out.xml > result.xmgr are correctly labeled, there are no points. Any ideas? Thanks, Austen

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Differences between ALPS 1.2.2 and 1.3.2 (TOTAL_MOMENTUM, ...)
by Cristian Degli Esposti Boschi 03 Dec '06

03 Dec '06

I recently installed ALPS (lib+apps), release version 1.2.2 and played a while also with a Live CD shipped with 1.3.2. Am I right that the tutorial on the web site are referred to the pre-release 1.3 ? In particular, using the same input files, with sparsediag of 1.2.2 I cannot produce any output as far as correlations are concerned while with 1.3.2 I can. What I find misleading is that with 1.2.2 I had no complain message about the parameters MEASURE_CORRELATIONS, that seem to be simply ignored. Well, apart from that, I find the implementation of TOTAL_MOMENTUM very useful (again it seems to be active only with 1.3.2). I wonder if the eigenvalue can be selected from input...how? More generally, which is the syntax to select two or more compatible quantum numbers? CONSERVED_QUANTUMNUMBERS="???"; I'm sorry but I couldn't find this last point on the wiki pages. Cheers, Cristian -- ___________________________________________________ Cristian Degli Esposti Boschi CNR-INFM, Unita' di Ricerca CNISM 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 2095153 e-mail: cristian.degliesposti -AT- unibo.it web: http://www.bo.infm.it/grp/morandi/home.html ___________________________________________________

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estimated time ??????
by Rakesh Kumar 11 Nov '06

11 Nov '06

Dear all, If I want sparse diagonalize Heisenberg Hamiltonian of 4x4 site cluster on square lattice. How much time will be take ? I running this program 3748 minutes but till now it is not ended. It seems very time consumable. With Best regards Rakesh Kumar School of Physical Sciences, JNU, New Delhi-110067 (INDIA) Mob.No.: +91-9891397108 --------------------------------- Get your own web address for just $1.99/1st yr. We'll help. Yahoo! Small Business.

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2D Hubbard
by Jeff Hammond 10 Nov '06

10 Nov '06

Dear ALPS users, I'm trying to get some benchmark numbers for the 2D Hubbard model. I'm figuring out the input from the tutorial and by reading the XML files and source code, but I wonder if there a more complete manual somewhere so I can optimize the input for conserved quantum numbers, etc.? I read the arXiv article and two Powerpoint presentations but haven't found what I'm looking for. For example, can I use SU(2) - | S^2 S_z > - configurations, or better yet, SO(4) - | S^2 S_z J^2 J_z > - configurations? It was mentioned somewhere that 1.3 would have spatial symmetry built in the diagonalization code but I could not run the 4x4 Hubbard on a workstation, which should have been possible if the translation and C4v groups were utilized. What is the status of that development? Given the current functionality, what should I need for the half-filled 4x4 Hubbard using Lanczos? I should have almost unlimited resources at NERSC but installation there is not going well and I'd rather use a 4 Xeon-core, 4 GB workstation if possible. Thanks for all your answers. Jeff UChicago

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