Triclinic unit cell to cubic unit cell transformation

pymatgen
,
1

I am trying to turn a triclinic unit cell into a cubic cell with the following code:

import pymatgen.core as pmg
from pymatgen.symmetry.analyzer import SpacegroupAnalyzer
from pymatgen.transformations.advanced_transformations import CubicSupercellTransformation

atoms = pmg.Structure.from_file('POSCAR')

symm_analyzer = SpacegroupAnalyzer(atoms)
transform = CubicSupercellTransformation(max_atoms=3000, min_atoms=150, force_diagonal=True, force_90_degrees=True,
        min_length=15.0, angle_tolerance=0.001)

cubic_supercell = transform.apply_transformation(atoms)

cubic_supercell.to(fmt="poscar", filename="POSCAR_cubic_supercell")

The code runs but it does not transform the actual unit cell into a cubic unit cell, it actually does nothing to the structure. Any input would be great!

2

Hi!

Have you already tried to play around with the different arguments?
Maybe relaxing some of the constraints to see if it returns something?

3

I am so late, but yes. I have tried relaxing the constrains like the angle tolerance, the min length, and increasing the max_atoms. For any sort of combination I either obtain a structure that resembles the initial triclinic one. Or (specially when increasing the max_atoms) I never obtain a structure.