1. Structure Optimization

This is a simple example of how to perform a structure optimization using the MatterSim.

1.1. Import the necessary modules

import numpy as np
from ase.build import bulk
from ase.units import GPa
from mattersim.forcefield.potential import MatterSimCalculator
from mattersim.applications.relax import Relaxer

1.2. Set up the structure to relax

# initialize the structure of silicon
si = bulk("Si", "diamond", a=5.43)

# perturb the structure
si.positions += 0.1 * np.random.randn(len(si), 3)

# attach the calculator to the atoms object
si.calc = MatterSimCalculator()

1.3. Run the relaxation

MatterSim implements a built-in relaxation class to support the relaxation of ase atoms.

# initialize the relaxation object
relaxer = Relaxer(
    optimizer="BFGS", # the optimization method
    filter="ExpCellFilter", # filter to apply to the cell
    constrain_symmetry=True, # whether to constrain the symmetry
)

relaxed_structure = relaxer.relax(si, steps=500)