mirror atomate2 fix and improve test_kspacing edge case coverage (#3396)

pymatgen/io/vasp/sets.py

@@ -977,10 +977,10 @@ def __init__(
         if self.bandgap < 1e-4:
             updates.update(KSPACING=0.22, SIGMA=0.2, ISMEAR=2)
         else:
-            rmin = 25.22 - 2.87 * bandgap  # Eq. 25
+            rmin = max(1.5, 25.22 - 2.87 * bandgap)  # Eq. 25
             kspacing = 2 * np.pi * 1.0265 / (rmin - 1.0183)  # Eq. 29
             # cap the KSPACING at a max of 0.44, per internal benchmarking
-            updates.update(KSPACING=kspacing if 0.22 < kspacing < 0.44 else 0.44, SIGMA=0.05, ISMEAR=-5)
+            updates.update(KSPACING=np.clip(kspacing, 0.22, 0.44), SIGMA=0.05, ISMEAR=-5)
 
         # Don't overwrite things the user has supplied
         for key in self.user_incar_settings:

tests/io/vasp/test_sets.py

@@ -1555,11 +1555,11 @@ def test_kspacing(self):
         # Test that KSPACING is capped at 0.44 for insulators
         file_path = f"{TEST_FILES_DIR}/POSCAR.O2"
         struct = Poscar.from_file(file_path, check_for_POTCAR=False).structure
-        for bandgap, expected in ((10, 0.44), (3, 0.4136617), (1.1, 0.3064757)):
+        for bandgap, expected in ((10, 0.44), (3, 0.4136617), (1.1, 0.3064757), (0.5, 0.2832948), (0, 0.22)):
             incar = MPScanRelaxSet(struct, bandgap=bandgap).incar
             assert incar["KSPACING"] == approx(expected, abs=1e-5)
-            assert incar["ISMEAR"] == -5
-            assert incar["SIGMA"] == 0.05
+            assert incar["ISMEAR"] == -5 if bandgap > 1e-4 else 2
+            assert incar["SIGMA"] == 0.05 if bandgap > 1e-4 else 0.2
 
     def test_incar_overrides(self):
         # use 'user_incar_settings' to override the KSPACING, ISMEAR, and SIGMA