Get quantities : e.g. magnetization

[Abdou137]

Dear all, I want to extract the magnetisation from a simulation, it gives the following error :

spirit.quantities.get_magnetization(p_state, idx_image=-1, idx_chain=-1) NameError: name 'spirit' is not defined

---

The code I used was simple :

import os
import sys

### Make sure to find the Spirit modules
### This is only needed if you did not install the package
spirit_py_dir = os.path.abspath(os.path.join(os.path.dirname( __file__ ), "../core/python"))
sys.path.insert(0, spirit_py_dir)

#from spirit import state
from spirit import io
from spirit import simulation
from spirit import configuration
from spirit import state

# Import Spirit modules
spirit_py_dir = os.path.abspath(os.path.join(
    os.path.dirname(__file__), "../core/python"))
sys.path.insert(0,spirit_py_dir ) 

with state.State("input/CrIiii_HC.cfg") as p_state:
    simulation.start(p_state, simulation.METHOD_LLG, simulation.SOLVER_SIB)
    spirit.quantities.get_magnetization(p_state, idx_image=-1, idx_chain=-1)

---

I didn't find where is the problem . thus I will appreciate any kind of help with nice regards

[GPMueller]

This has nothing to do with Spirit. Please familiarize yourself with the way Python imports work (as the error already tells you, you cannot use something you neither defined nor imported). My tip: look at the usage of the simulation submodule and use the quantities submodule in the same way.

[Abdou137]

Dear Mr. MUELLER, Thank you very much , I fixed it I think.

• But , there are moslty OVF files in the output , although I asked to get magnetization: How one gets the magnetisation in order to draw hysteresis loop of a lattice ? To get the hysteresis loop, I wanted to do the follwoing : give a value for the external magnetic field , then run simulation , then get the magnetisation repeat the previous steps for different values of the external field then plot the magnetisation vs the external magnetic field . not sure if this will work , and not sure if there is another more efficient way

• By another issue: I am trying to run a python file example provided in the github "https://github.com/spirit-code/spirit/tree/master/ui-python " whose name is (main.py), but it gives the following error:

  File "main.py", line 154, in configurations(p_state) File "main.py", line 29, in configurations chain.Image_to_Clipboard(p_state) AttributeError: module 'spirit.chain' has no attribute 'Image_to_Clipboard'

• if one asked to get some quantities ( magnetization .......) for instance using: quantities.get_magnetization(p_state) where could one find these quantities in the output files ? I didn't find the magnetization

I will appreciate any kind of help with nice regards

[GPMueller]

Maybe you found these things on your own already, but in case not:

1. it depends on how you'd like to do it. You can of course read the orientations from the ovf file, or you could use the system.get_spin_directions API method: https://spirit-docs.readthedocs.io/en/latest/core/docs/python-api/spirit.system.html#spirit.system.get_spin_directions - calculating the magnetization values from these arrays is of course trivial
2. you can look at ui-python/mc.py for some inspiration, but the way you describe calculating the hysteresis is conceptually ok
3. there is no ui-python/main.py on the develop branch. If you want to run that older file, you need to update the function names to the ones given in the documentation
4. See the documentation on the input parameters for the available output files. Any other output you wish to have you can simply write yourself - it is very easy to do in Python