Dear Synge,

   I just removed param2d and used tutorial2d.py as

import pyalps
import matplotlib.pyplot as plt
import pyalps.plot

#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"
        }
    )

#write the input file and run the simulation
input_file = pyalps.writeInputFiles('parm2d',parms)
pyalps.runApplication('loop',input_file)

#load the susceptibility and collect it as function of temperature T
data = pyalps.loadMeasurements(pyalps.getResultFiles(prefix='parm2d'),'Susceptibility')
susceptibility = pyalps.collectXY(data,x='T',y='Susceptibility')

#make plot
plt.figure()
pyalps.plot.plot(susceptibility)
plt.xlabel('Temperature $T/J$')
plt.ylabel('Susceptibility $\chi J$')
plt.ylim(0,0.22)
plt.title('Quantum Heisenberg ladder')
plt.show()

Then typed alpspython tutorial2d.py and it shows the same situation again.....

/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UserWarning: In /usr/share/matplotlib/stylelib/classic.mplstyle: text.dvipnghack is obsolete.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@comp-phys.org>

using ALPS/parapack scheduler
  a Monte Carlo scheduler for multiple-level parallelization
  copyright (c) 1997-2016 by Synge Todo <wistaria@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 14:54:16]: 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 14:54:16]: task status: total number of tasks = 15
  new = 15, running = 0, continuing = 0, suspended = 0, finished = 0, completed = 0, skipped = 0
[2018-Aug-03 14:54:16]: starting 1 threadgroup(s)
[2018-Aug-03 14:54:16]: dispatching a new clone[1,1] on threadgroup[1]

Thanks,

Santu

On 3 August 2018 at 14:51, Synge Todo <wistaria@phys.s.u-tokyo.ac.jp> wrote:

Dear Santu,

Strange.  Could you remove parm2d.* in your working directory and run tutorial2d.py again?

BTW, 2d lattice with L=60 is a bit large as a starting point. I would recommend you to begin with
smaller value, say, L=8.

Best,
Synge


> 2018/08/03 14:39、S Baidya <santubaidya2009@gmail.com>のメール:

>
> Dear Synge,
>
>   Thank you for your reply. I then made a small mistake. The "J" value should be "-4.2" as it is FM. If it is now FM it should work like ising model in any 2d lattice. But I am still getting the same error.
>
> Is there any other solution for dealing this situation.
>
>
> Thanking you,
>
> Santu
>
>
>
> On 3 August 2018 at 14:30, Synge Todo <wistaria@phys.s.u-tokyo.ac.jp> wrote:
> Dear Santu Baidya,
>
> The antiferromagnetic (positive J) Heisenberg model on the kagome lattice has frustration.
> This causes the so-called negative sign problem in the quantum Monte Carlo methods.
> Although the loop code can simulate such a system and produce some numbers, the errorbar
> becomes very large especially at low temperatures.
>
> You can use the exact diagonalization for the frustrated spin models, but the lattice size is
> very limited in this case due to the spin size S=3/2.
>
> Best,
> Synge
>
>
> > 2018/08/03 14:10、S Baidya <santubaidya2009@gmail.com>のメール:
> >
> > 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@comp-phys.org>
> >
> > using ALPS/parapack scheduler
> >   a Monte Carlo scheduler for multiple-level parallelization
> >   copyright (c) 1997-2016 by Synge Todo <wistaria@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
> >
> >
> >
> >
> >
> >
> > ----
> > Comp-phys-alps-users Mailing List for the ALPS Project
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