Regarding lattice coordinate structure in v.5 and v.7

[Swaroop Panda]

Hi All,

I am doing a hysteresis-loop calculation of a kagome magnet (attached input file). I have the following two questions. I'll appreciate any help.

1. When I use v.5 and v.7 of VAMPIRE, I get different lattice structures (also attached here). I see nice hysteresis features in magnetization when I use v.7 but not in v.5. But the lattice structure obtained in v.5 appears correctly. I have attached here the matlab plotting code that I am using for lattice visualization. In the unit cell definition in the input file, I used rectangular representation of the kagome lattice and while plotting the lattice, I am transforming back the coordinates. This worked in v.5 but v.7 is showing a triangular lattice. 

2. If I want to do an MC annealing simulation at zero-field (B=0) and later do the field-sweep starting with the annealed spin-configuration, how should my input file change.

Please let me know if more information is needed.

Many thanks for your time,

Yours sincerely,

Swaroop Panda

PhD student, Delhi, India

[Richard Evans]

Hi Swaroop,

1) Apologies - I thought I had pushed a fix for this. I have just updated the develop branch which now generates the correct structure in 3D, but can be used for monolayers too and also with sublattice material support. Please do the following to get this:

git checkout develop

git pull origin develop

make clean

make serial

make parallel

2) You can use checkpoints for this - 

sim:save-checkpoint = end 

will save the configuration.

sim:load-checkpoint = restart

will reload the configuration.

All the best,

Richard

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<input><lattice_v5.png><plot_lattice.m><lattice_v7.png>

[Swaroop Panda]

Many thanks Prof. Richard for looking into this and the suggestions. I'll try these methods.

Yours sincerely,

Swaroop

[Swaroop Panda]

I tried running with the develop version using my same input files. The result is still the same. It seems like it is not reading the atoms at coordinates (0.0,0.5) and (0.5,0.0). 

I am using a cubic unit cell having three atoms (with transformed coordinates). I have attached my ucf file here. Is anything wrong in the ucf file?

Yours sincerely,

Swaroop

[gabo...@gmail.com]

Thanks for sharing plot_lattice.m.  I like how it works with Octave.

When running VAMPIRE 7.0.0, does the terminal output from executing (e.g., vampire-serial) show commit c3e38ec?

Used from [1]:

input
plot_lattice.m

Used from [2]:

unit_cell_file.ucf

Used attached material.mat as a test file.

username@computername:~$ git clone https://github.com/richard-evans/vampire.git
...
username@computername:~$ cd vampire/
username@computername:~/vampire$ git checkout develop
username@computername:~/vampire$ make
...
username@computername:~/vampire$ cd ../test
username@computername:~/test$ ls -l
total 16
-rw-r--r-- 1 username username 1594 Apr 17 13:12 input
-rw-r--r-- 1 username username  846 Apr 17 11:40 material.mat
-rw-r--r-- 1 username username 2192 Apr 17 13:12 plot_lattice.m
-rw-r--r-- 1 username username 3019 Apr 17 13:13 unit_cell_file.ucf
username@computername:~/test$ ~/vampire/vampire-serial
                                                _          
                                               (_)        
                    __   ____ _ _ __ ___  _ __  _ _ __ ___
                    \ \ / / _` | '_ ` _ \| '_ \| | '__/ _ \
                     \ V / (_| | | | | | | |_) | | | |  __/
                      \_/ \__,_|_| |_| |_| .__/|_|_|  \___|
                                         | |              
                                         |_|              

                      Version 7.0.0 Apr 17 2026 19:18:46

             Git commit: c3e38ec6134e8bb9342f1b2c4cd8406a7820ad49
...
Simulation ended gracefully.
username@computername:~/test$ ~/vampire/util/vdc/vdc --xyz
|------------------------------------------------------------|
|              Vampire Data Converter for v5+                |
|------------------------------------------------------------|
Processing snapshot 00000000
...
Processing snapshot 00000081
username@computername:~/test$ awk 'NR > 2 {print $2, $3}' crystal.xyz > coords.dat
username@computername:~/test$ octave --persist plot_lattice.m

[1] https://groups.google.com/g/vampire-users/c/n96ocb4yBDM/m/AeIHwZj9AwAJ
[2] https://groups.google.com/g/vampire-users/c/n96ocb4yBDM/m/FE0awrq2BAAJ

Best Regards,

Gavin

VAMPIRE user

[Swaroop Panda]

Hi Gavin,

Many thanks for looking into this. Earlier my output was not showing commit c3e38ec; I have fixed it now and the problem is resolved.

Yours sincerely,

Swaroop

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