Fix the minor document error in POTCAR Setup.

[hongyi-zhao]

closes #3830. see there for more details.

[DanielYang59]

I think these paths look correct to me, perhaps I'm wrong.

The potcar_PBE/LDA.54/ in the first two paths refers to the directory where the POTCARs are stored.

The last path looks a bit confusing, perhaps:

- pmg config --add PMG_VASP_PSP_DIR /path/to/pseudos/pmg_potcars/pmg_potcars
+ pmg config --add PMG_VASP_PSP_DIR /path/to/pseudos/pmg_potcars/POTCARs

[hongyi-zhao]

For the last path looks a bit confusing, perhaps:

- pmg config --add PMG_VASP_PSP_DIR /path/to/pseudos/pmg_potcars/pmg_potcars
+ pmg config --add PMG_VASP_PSP_DIR /path/to/pseudos/pmg_potcars/POTCARs

No. The PMG_VASP_PSP_DIR must point to the top directory of potcars generated by pmg, aka, the pmg_potcars directory used here.

In my case, the relevant configuration and test information are as follows, for your reference only:

werner@x13dai-t:~$ cat ~/.pmgrc.yaml
PMG_DEFAULT_FUNCTIONAL: PBE_64
PMG_MAPI_KEY: <my-MAPI_KEY>
PMG_VASP_PSP_DIR: /home/werner/Public/hpc/vasp/pot/pmg_potcar

werner@x13dai-t:~$ ls -l ~/Public/hpc/vasp/pot/pmg_potcar
total 28
drwxrwxr-x 2 werner werner 12288  2月  3 16:43 POT_LDA_PAW_64
drwxrwxr-x 2 werner werner 16384  2月  3 16:43 POT_PAW_PBE_64

werner@x13dai-t:~$ pyenv shell datasci 
(datasci) werner@x13dai-t:~$ ipython
Python 3.11.1 (main, Dec 22 2022, 17:06:07) [GCC 12.2.0]
Type 'copyright', 'credits' or 'license' for more information
IPython 8.14.0 -- An enhanced Interactive Python. Type '?' for help.
Installed qt5 event loop hook.
Shell is already running a gui event loop for qt5. Call with no arguments to disable the current loop.

In [1]: from mp_api.client import MPRester
   ...: from pymatgen.io.vasp.sets import MPRelaxSet
   ...: with MPRester() as mpr:
   ...:     structure = mpr.get_structure_by_material_id("mp-2469")
   ...: relax_set = MPRelaxSet(structure)
   ...: relax_set.user_potcar_functional = "PBE_64"  # Specifically designate the POTCAR functional as P
   ...: BE_64
   ...: try:
   ...:     potcar_symbols = relax_set.potcar_symbols
   ...:     print("Successfully prepared POTCAR metadata with PBE_64 functional. Here are the symbols:")
   ...: 
   ...:     print(potcar_symbols)
   ...: except Exception as e:
   ...:     print(f"Error occurred while attempting to prepare POTCAR metadata: {e}")
   ...: 
Retrieving MaterialsDoc documents: 100%|███████████████████████████████| 1/1 [00:00<00:00, 19508.39it/s]
Successfully prepared POTCAR metadata with PBE_64 functional. Here are the symbols:
['Cd', 'S']

The corresponding source code implementation is here:

pymatgen/pymatgen/io/vasp/inputs.py

Lines 2269 to 2307 in 14b7357

	def from_symbol_and_functional(
	cls,
	symbol: str,
	functional: str | None = None,
	) -> Self:
	"""Make a PotcarSingle from a symbol and functional.
	Args:
	symbol (str): Symbol, e.g. Li_sv
	functional (str): Functional, e.g. PBE
	Returns:
	PotcarSingle
	"""
	functional = functional or SETTINGS.get("PMG_DEFAULT_FUNCTIONAL", "PBE")
	if functional is None:
	raise ValueError("Cannot get functional.")
	funcdir = cls.functional_dir[functional]
	PMG_VASP_PSP_DIR = SETTINGS.get("PMG_VASP_PSP_DIR")
	if PMG_VASP_PSP_DIR is None:
	raise ValueError(
	f"No POTCAR for {symbol} with {functional=} found. Please set the PMG_VASP_PSP_DIR in .pmgrc.yaml."
	)
	paths_to_try: list[str] = [
	os.path.join(PMG_VASP_PSP_DIR, funcdir, f"POTCAR.{symbol}"),
	os.path.join(PMG_VASP_PSP_DIR, funcdir, symbol, "POTCAR"),
	]
	for path in paths_to_try:
	path = os.path.expanduser(path)
	path = zpath(path)
	if os.path.isfile(path):
	return cls.from_file(path)
	raise RuntimeError(
	f"You do not have the right POTCAR with {functional=} and {symbol=} "
	f"in your {PMG_VASP_PSP_DIR=}. Paths tried: {paths_to_try}"
	)

See here for the related discussion.

[DanielYang59]

Make sense to me, sorry for the stupid question (I'm not an activate user of the pmg cli tool).

[janosh]

thanks @hongyi-zhao for reporting and fixing! 👍