Support for nested folders (e.g., NEB runs) in VaspDir class.

src/pymatgen/io/vasp/outputs.py

@@ -5765,6 +5765,7 @@ class VaspDir(collections.abc.Mapping):
         "POSCAR": Poscar,
         "CONTCAR": Poscar,
         "KPOINTS": Kpoints,
+        "IBZKPT": Kpoints,
         "POTCAR": Potcar,
         "vasprun": Vasprun,
         "OUTCAR": Outcar,
@@ -5786,16 +5787,16 @@ def __init__(self, dirname: str | Path):
         Args:
             dirname: The directory containing the VASP calculation as a string or Path.
         """
-        self.path = Path(dirname)
-        self.files = [f.name for f in self.path.iterdir() if f.is_file()]
+        self.path = Path(dirname).absolute()
+        self.files = [Path(d) / f for d, subd, fnames in os.walk(self.path) for f in fnames]
         self._parsed_files: dict[str, Any] = {}
 
     def reset(self):
         """
         Reset all loaded files and recheck the directory for files. Use this when the contents of the directory has
         changed.
         """
-        self.files = [f for f in self.path.iterdir() if f.is_file()]
+        self.files = [Path(d) / f for d, subd, fnames in os.walk(self.path) for f in fnames]
         self._parsed_files = {}
 
     def __len__(self):

tests/io/vasp/test_outputs.py

@@ -2196,6 +2196,12 @@ def test_getitem(self):
         with pytest.raises(ValueError, match="hello not found"):
             d["hello"]
 
-        d = VaspDir(f"{TEST_FILES_DIR}/io/vasp/outputs")
-        with pytest.warns(UserWarning, match=r"No parser defined for IBZKPT.*"):
-            assert isinstance(d["IBZKPT.lobster"], str)
+        d = VaspDir(f"{TEST_FILES_DIR}/io/pwscf")
+        with pytest.warns(UserWarning, match=r"No parser defined for Si.pwscf.out"):
+            assert isinstance(d["Si.pwscf.out"], str)
+
+        # Test NEB directories.
+        d = VaspDir(f"{TEST_FILES_DIR}/io/vasp/fixtures/neb_analysis/neb1/neb")
+        assert len(d) == 10
+
+        assert isinstance(d["00/POSCAR"], Poscar)