kpt_check.py

kpt_check.py can check a k-point mesh with a given kppvol. This script supports POSCAR, CONTCAR, and init_struc_data.pkl. pymatgen library is required.

After generating initial structures, you can try to see how much the value of kppvol should be.

Usage

python3 kpt_check.py -h

or if you put the script in your PATH, you can omit python3

kpt_check.py -h
usage: kpt_check.py [-h] [-w] [-n NSTRUC] infile kppvol

positional arguments:
  infile                input file: POSCAR, CONTCAR, or init_struc_data.pkl
  kppvol                kppvol

options:
  -h, --help            show this help message and exit
  -w, --write           write KPOINTS
  -n NSTRUC, --nstruc NSTRUC
                        number of structure to check

Example

POSCAR with a Given kppvol

kpt_check.py POSCAR 100
a = 10.689217
b = 10.689217
c = 10.730846
    Lattice vector
10.689217 0.000000 0.000000
0.000000 10.689217 0.000000
0.000000 0.000000 10.730846

kppvol:  100
k-points:  [2, 2, 2]

Write KPOINTS File

You can generate a KPOINTS file using -w option.

kpt_check.py -w POSCAR 100
$ cat KPOINTS
pymatgen 4.7.6+ generated KPOINTS with grid density = 607 / atom
0
Monkhorst
2 2 2

Check K-Point Meshes for init_struc_data.pkl

In checking k-point meshes for init_struc_data.pkl, first five structures are automatically checked in the default setting. You can change the number of structures using -n option.

kpt_check.py -n 3 init_struc_data.pkl 100
# ---------- 0th structure
a = 8.0343076893
b = 8.03430768936
c = 9.1723323373
    Lattice vector
8.034308 0.000000 0.000000
-4.017154 6.957915 0.000000
0.000000 0.000000 9.172332

kppvol:  100
k-points:  [3, 3, 3]


# ---------- 1th structure
a = 9.8451944096
b = 9.84519440959
c = 6.8764313585
    Lattice vector
9.845194 0.000000 0.000000
-4.922597 8.526188 0.000000
0.000000 0.000000 6.876431

kppvol:  100
k-points:  [3, 3, 4]


# ---------- 2th structure
a = 7.5760383679
b = 7.57603836797
c = 6.6507478296
    Lattice vector
7.576038 0.000000 0.000000
-3.788019 6.561042 0.000000
0.000000 0.000000 6.650748

kppvol:  100
k-points:  [4, 4, 4]