August 2018 - Comp-phys-alps-users

The specific heat per site different for spinmc and qwl method!!!!!
by S Baidya 31 Aug '18

31 Aug '18

Dear ALPS users, I calculated specific heat capacity for square lattice with similar parameters, for spinmc (classical monte carlo) and qwl (qmc) for a square lattice. For spinmc, #prepare the input parameters parms = [] for l in [40]: for t in [5.0,4.5,4.0,3.5,3.0,2.9,2.8,2.7]: parms.append( { 'LATTICE' : "square lattice", 'T' : t, 'S' : 0.5, 'J' : 1 , 'THERMALIZATION' : 1000, 'SWEEPS' : 400000, 'UPDATE' : "cluster", 'MODEL' : "Ising", 'L' : l } ) for t in [2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.2]: parms.append( { 'LATTICE' : "square lattice", 'T' : t, 'S' : 0.5, 'J' : 1 , 'THERMALIZATION' : 1000, 'SWEEPS' : 40000, 'UPDATE' : "cluster", 'MODEL' : "Ising", 'L' : l } ) #write the input file and run the simulation input_file = pyalps.writeInputFiles('parm7a',parms) pyalps.runApplication('spinmc',input_file,Tmin=5) For qwl, #prepare the input parameters parms = [{ 'LATTICE' : "square lattice", 'MODEL' : "spin", 'local_S' : 0.5, 'L' : 40, 'J' : -1 , 'Jxy' : 0, 'CUTOFF' : 1000 }] #write the input file and run the simulation input_file = pyalps.writeInputFiles('parm6a',parms) res = pyalps.runApplication('qwl',input_file) #run the evaluation and load all the plots data = pyalps.evaluateQWL(pyalps.getResultFiles(prefix='parm6a'),DELTA_T=0.1, T_MIN=0.1, T_MAX=10.0) I hoped that the two results should not show completely different specific heat per site curve with temperature. But, they are totally different. Can anyone please tell me if it is expected that classical and quantum result are completely different. Thanking you, Santu Baidya

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Interaction involving three lattice sites
by Julien DESPRES 30 Aug '18

30 Aug '18

Dear ALPS community, I was wondering if it is possible to define an interaction involving three different lattice sites (for a 1D lattice model to perform dmrg calculations). To clarify, an example would be to construct the term \sum_i n_i n_{i+1} n_{i-1}. I checked in the doc if anyone had already the same kind of problem but it seems not. I guess that the solution is to build a bond term in the definition of the Hamiltonian by specifying the source and targets and to modify accordingly the lattice. Or is there a trick to specify one source (i) and two targets (i+1, i-1) ? Thanks in advance, Julien Ps : Just realized that I forgot to modify the subject (short vacations ...) -- __________________________________ DESPRES Julien Ph.D. student Center for Theoretical Physics Quantum Matter Theory team Ecole Polytechnique 91128 Palaiseau Cedex France, EU Office : 00.10.06 (ground floor) Phone : +33 1 69 33 42 81 Laboratoire Charles Fabry Atom Optics group Institut d'Optique Graduate School 2 Avenue Augustin Fresnel 91127 Palaiseau Cedex France, EU Office : R2.29 (1st floor) Phone: +33 1 64 53 33 49 __________________________________

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What is the factor in Temperature unit when doing thermalization
by S Baidya 14 Aug '18

14 Aug '18

Dear Alps users, I tried to look into the examples and files in the alps directory to find the actual factor of temperature variable (T). In magnetization vs temperature plot in the example number mc-07 the plot shows temperature range of 0 to 5 in Kelvin. I need to know if the T is exactly T or with same factor. Where can I find the program to specify this details. Sometime T should be around 300-4000 K kelvin range but it still shows temperature around 5 - 8 Kelvin . Thank you, Santu Baidya

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ALPS code error with Kagome spin lattice to calculate susceptibility
by S Baidya 08 Aug '18

08 Aug '18

Dear Alps users, I am totally new to ALPS code using quantum monte carlo. I have started to use this code for few small purpose like magnetic suceptibility vs temperature for various spin lattice models. Currently I have used ALPS code for calculating susceptibility for ising type S=3/2 Kagome lattice. I found in the lattice library that Kagome lattice is defined. So in the tutorial mc-02-susceptibilities/ I changed tutorial2d.py by editing #prepare the input parameters parms = [] for t in [0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.25, 1.5, 1.75, 2.0]: parms.append( { 'LATTICE' : "Kagome lattice", 'MODEL' : "spin", 'local_S' : 1.5, 'T' : t, 'J' : 4.2 , 'THERMALIZATION' : 5000, 'SWEEPS' : 50000, 'L' : 60, 'ALGORITHM' : "loop" } ) Then I changed the same way param2d file and ran the alpspython tutorial2d.py and I got strange error /usr/local/lib/python2.7/dist-packages/matplotlib/style/core.py:203: UserWarning: In /usr/share/matplotlib/stylelib/classic.mplstyle: text.dvipnghack is obsolete. Please remove it from your matplotlibrc and/or style files. warnings.warn(message) loop parm2d.in.xml ALPS/looper version 3.2b12-20100128 (2010/01/28) multi-cluster quantum Monte Carlo algorithms for spin systems available from http://wistaria.comp-phys.org/alps-looper/ copyright (c) 1997-2010 by Synge Todo <wistaria(a)comp-phys.org> using ALPS/parapack scheduler a Monte Carlo scheduler for multiple-level parallelization copyright (c) 1997-2016 by Synge Todo <wistaria(a)comp-phys.org> based on the ALPS libraries version 2.3.0 available from http://alps.comp-phys.org/ copyright (c) 1994-2016 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. [2018-Aug-03 14:02:51]: starting scheduler on cces-System-Product-Name master input file = /home/cces/kagome-alps/mc-02/parm2d.in.xml master output file = /home/cces/kagome-alps/mc-02/parm2d.out.xml termination file = [disabled] total number of thread(s) = 1 thread(s) per clone = 1 number of thread group(s) = 1 auto evaluation = yes time limit = unlimited interval between checkpointing = 3600 seconds interval between progress report = 600 seconds interval between vmusage report = infinity task range = all worker dump format = hdf5 worker dump policy = running workers only [2018-Aug-03 14:02:51]: task status: total number of tasks = 15 new = 15, running = 0, continuing = 0, suspended = 0, finished = 0, completed = 0, skipped = 0 [2018-Aug-03 14:02:51]: starting 1 threadgroup(s) [2018-Aug-03 14:02:51]: dispatching a new clone[1,1] on threadgroup[1] WARNING: model is classically frustrated WARNING: model has negative signs I donot understand the actual reason and how to solve this situation. I used this tutorial before and it worked for ladder spin lattice. Can anyone please tell me what should I do to solve this situation. Thanking you, Santu Baidya

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