ASE on Your Local PC

Last updated: October 16, 2026

The files used in this tutorial can be downloaded from CrySPY_utility/examples/ase_Cu8Au8_EA. This tutorial demonstrates a test run on a local machine using ASE’s lightweight Pure Python EMT calculator. The target system is Cu8Au8.

cryspy.in

Example of cryspy.in.

[basic]
algo = EA
calc_code = ASE
nstage = 1
njob = 5
jobcmd = zsh
jobfile = job_cryspy

[structure]
atype = Cu Au
nat = 8 8

[EA]
n_pop = 10
n_crsov = 5
n_perm = 2
n_strain = 2
n_rand = 1
n_elite = 1
n_fittest = 5
slct_func = TNM
t_size = 2
maxgen_ea = 0

[ASE]
ase_python = ase_in.py

[option]
rslt_out = always
energy_output_interval = 1
backup_interval = 1

Use algo = EA.
From v1.5.0, energy_output_interval in the [option] section sets the output interval in generations for the energy plot. Default: 1 (every generation); 0 disables automatic output.
From v1.5.0, backup_interval in the [option] section sets the automatic backup interval in generations. The default is 1; 0 disables automatic backups. See Features > Backup for details.
When using a bash environment, set jobcmd to bash.
In EA, tot_struc is not used. The number of structures is determined by n_pop.
n_pop = n_crsov + n_perm + n_strain + n_rand
For parameters in the [EA] section, refer to Input file > [EA] section and Search algorithms > Evolutionary algorithm (EA).

calc_in/

The contents under calc_in/ are the same as in Tutorial > Random Search (RS) > ASE in your local PC.

calc_in/ase_in.py_1

from ase.constraints import FixSymmetry
from ase.filters import FrechetCellFilter
from ase.calculators.emt import EMT
from ase.optimize import BFGS
from ase.io import read, write

# ---------- input structure
# CrySPY outputs 'POSCAR' as an input file in work/xxxxxx directory
atoms = read('POSCAR', format='vasp')

# ---------- setting and run
atoms.calc = EMT()
atoms.set_constraint([FixSymmetry(atoms)])
cell_filter = FrechetCellFilter(atoms, hydrostatic_strain=False)
opt = BFGS(cell_filter)

# ---------- run
converged = opt.run(fmax=0.01, steps=2000)

# ---------- rule in ASE interface
# output file for energy: 'log.tote' in eV/cell
#                         CrySPY reads the last line of 'log.tote' file
# outimized structure: 'CONTCAR' file in vasp format
# check_opt: 'out_check_opt' file ('done' or 'not yet')
#                         CrySPY reads the last line of 'out_check_opt' file

# ------ energy
e = cell_filter.atoms.get_total_energy()    # eV/cell
with open('log.tote', mode='w') as f:
    f.write(str(e))

# ------ struc
opt_atoms = cell_filter.atoms.copy()
opt_atoms.set_constraint(None)    # remove constraint for pymatgen
write('CONTCAR', opt_atoms, format='vasp', direct=True)

# ------ check_opt
with open('out_check_opt', mode='w') as f:
    if converged:
        f.write('done\n')
    else:
        f.write('not yet\n')

calc_in/job_cryspy

#!/bin/sh

# ---------- ASE
python3 ase_in.py > out.log