add error message

deepmd/utils/data_system.py

@@ -100,6 +100,7 @@ def __init__(
         del rcut
         self.system_dirs = systems
         self.nsystems = len(self.system_dirs)
+        assert self.nsystems > 0, "No systems provided"
         self.data_systems = []
         for ii in self.system_dirs:
             self.data_systems.append(
@@ -752,12 +753,7 @@ def process_systems(systems: Union[str, list[str]]) -> list[str]:
         systems = expand_sys_str(systems)
     elif isinstance(systems, list):
         systems = systems.copy()
-    help_msg = "Please check your setting for data systems"
-    # check length of systems
-    if len(systems) == 0:
-        msg = "Cannot find any valid data systems"
-        log.fatal(msg)
-        raise OSError(msg, help_msg)
+    assert systems, "No systems provided"
     return systems
 
 

deepmd/utils/path.py

@@ -14,6 +14,7 @@
 from typing import (
     ClassVar,
     Optional,
+    Union,
 )
 
 import h5py
@@ -157,19 +158,18 @@ class DPOSPath(DPPath):
 
     Parameters
     ----------
-    path : str
+    path : Union[str, Path]
         path
     mode : str, optional
         mode, by default "r"
     """
 
-    def __init__(self, path: str, mode: str = "r") -> None:
+    def __init__(self, path: Union[str, Path], mode: str = "r") -> None:
         super().__init__()
         self.mode = mode
-        if isinstance(path, Path):
-            self.path = path
-        else:
-            self.path = Path(path)
+        self.path = Path(path)
+        if not self.path.exists():
+            raise FileNotFoundError(f"{self.path} not found")
 
     def load_numpy(self) -> np.ndarray:
         """Load NumPy array.
@@ -300,6 +300,8 @@ def __init__(self, path: str, mode: str = "r") -> None:
         # so we do not support file names containing #...
         s = path.split("#")
         self.root_path = s[0]
+        if not os.path.isfile(self.root_path):
+            raise FileNotFoundError(f"{self.root_path} not found")
         self.root = self._load_h5py(s[0], mode)
         # h5 path: default is the root path
         self._name = s[1] if len(s) > 1 else "/"