VaspInput setter and Incar.check_params() are inconsistent

[yantar92]

Python version

Python 3.12.4

Pymatgen version

2024.7.18

Operating system version

No response

Current behavior

When I set INCAR parametrs via vasp_input['INCAR']['PARAM']=value, they do not always pass Incar.check_params() checks.

Using the example below, I am getting:

...: BadIncarWarning: ENCUT: 550 is not a float
  vasp_input.incar.check_params()
...: BadIncarWarning: GGA: Cannot find Ps in the list of values
  vasp_input.incar.check_params()

Expected Behavior

Setting the parameters passes the checks.

Minimal example

from pymatgen.io.vasp.inputs import VaspInput
vasp_input = VaspInput.from_directory('.')
vasp_input['INCAR']['GGA'] = "MK"
vasp_input['INCAR']['GGA']

Relevant files to reproduce this bug

I used the following INCAR

ALGO = Normal
ENCUT = 550
ISMEAR = 0
NCORE = 16
SIGMA = 0.04
SYSTEM = C.hexagonal.191

Other requried inputs may be anything.

[DanielYang59]

Thanks for reporting this, I believe the warning on GGA=PS is owing to:

pymatgen/src/pymatgen/io/vasp/inputs.py

Line 988 in 4f7aa35

return val.strip().capitalize()

I.e. any keyword not included inside the following and is not boolean/float/int (str) would be capitalized:

pymatgen/src/pymatgen/io/vasp/inputs.py

Lines 876 to 932 in 4f7aa35

	list_keys = (
	"LDAUU",
	"LDAUL",
	"LDAUJ",
	"MAGMOM",
	"DIPOL",
	"LANGEVIN_GAMMA",
	"QUAD_EFG",
	"EINT",
	)
	bool_keys = (
	"LDAU",
	"LWAVE",
	"LSCALU",
	"LCHARG",
	"LPLANE",
	"LUSE_VDW",
	"LHFCALC",
	"ADDGRID",
	"LSORBIT",
	"LNONCOLLINEAR",
	)
	float_keys = (
	"EDIFF",
	"SIGMA",
	"TIME",
	"ENCUTFOCK",
	"HFSCREEN",
	"POTIM",
	"EDIFFG",
	"AGGAC",
	"PARAM1",
	"PARAM2",
	)
	int_keys = (
	"NSW",
	"NBANDS",
	"NELMIN",
	"ISIF",
	"IBRION",
	"ISPIN",
	"ISTART",
	"ICHARG",
	"NELM",
	"ISMEAR",
	"NPAR",
	"LDAUPRINT",
	"LMAXMIX",
	"ENCUT",
	"NSIM",
	"NKRED",
	"NUPDOWN",
	"ISPIND",
	"LDAUTYPE",
	"IVDW",
	)
	lower_str_keys = ("ML_MODE",)

---

The warning on ENCUT=550 should be owing to the incorrect classification of it into int_keys instead of float_keys:

pymatgen/src/pymatgen/io/vasp/inputs.py

Lines 910 to 924 in 4f7aa35

	int_keys = (
	"NSW",
	"NBANDS",
	"NELMIN",
	"ISIF",
	"IBRION",
	"ISPIN",
	"ISTART",
	"ICHARG",
	"NELM",
	"ISMEAR",
	"NPAR",
	"LDAUPRINT",
	"LMAXMIX",
	"ENCUT",

I believe it should be a float:

ENCUT = [real]