replace paths in basedataset with path

src/fairchem/core/datasets/base_dataset.py

@@ -52,13 +52,13 @@ def __init__(self, config: dict):
             config (dict): dataset configuration
         """
         self.config = config
-        self.paths = []
+        self.path = None
 
         if "src" in self.config:
             if isinstance(config["src"], str):
-                self.paths = [Path(self.config["src"])]
+                self.path = Path(self.config["src"])
             else:
-                self.paths = tuple(Path(path) for path in config["src"])
+                raise ValueError("path is required to be a single path")
 
         self.lin_ref = None
         if self.config.get("lin_ref", False):
@@ -82,34 +82,27 @@ def indices(self):
     @cached_property
     def _metadata(self) -> DatasetMetadata:
         # logic to read metadata file here
-        metadata_npzs = []
+        metadata_npz = None
         if self.config.get("metadata_path", None) is not None:
-            metadata_npzs.append(
-                np.load(self.config["metadata_path"], allow_pickle=True)
-            )
+            metadata_npz = np.load(self.config["metadata_path"], allow_pickle=True)
 
         else:
-            for path in self.paths:
-                if path.is_file():
-                    metadata_file = path.parent / "metadata.npz"
-                else:
-                    metadata_file = path / "metadata.npz"
-                if metadata_file.is_file():
-                    metadata_npzs.append(np.load(metadata_file, allow_pickle=True))
-
-        if len(metadata_npzs) == 0:
+            if self.path.is_file():
+                metadata_file = self.path.parent / "metadata.npz"
+            else:
+                metadata_file = self.path / "metadata.npz"
+            if metadata_file.is_file():
+                metadata_npz = np.load(metadata_file, allow_pickle=True)
+
+        if metadata_npz is None:
             logging.warning(
-                f"Could not find dataset metadata.npz files in '{self.paths}'"
+                f"Could not find dataset metadata.npz file for '{self.path}'"
             )
             return None
 
         metadata = DatasetMetadata(
-            **{
-                field: np.concatenate([metadata[field] for metadata in metadata_npzs])
-                for field in DatasetMetadata._fields
-            }
+            **{field: metadata_npz[field] for field in DatasetMetadata._fields}
         )
-
         assert metadata.natoms.shape[0] == len(
             self
         ), "Loaded metadata and dataset size mismatch."

src/fairchem/core/datasets/lmdb_dataset.py

@@ -58,11 +58,6 @@ def __init__(self, config) -> None:
             "train_on_oc20_total_energies", False
         ), "For training on total energies set dataset=oc22_lmdb"
 
-        assert (
-            len(self.paths) == 1
-        ), f"{type(self)} does not support a list of src paths."
-        self.path = self.paths[0]
-
         if not self.path.is_file():
             db_paths = sorted(self.path.glob("*.lmdb"))
             assert len(db_paths) > 0, f"No LMDBs found in '{self.path}'"

src/fairchem/core/datasets/oc22_lmdb_dataset.py

@@ -44,11 +44,6 @@ class OC22LmdbDataset(BaseDataset):
     def __init__(self, config, transform=None) -> None:
         super().__init__(config)
 
-        assert (
-            len(self.paths) == 1
-        ), f"{type(self)} does not support a list of src paths."
-        self.path = self.paths[0]
-
         self.data2train = self.config.get("data2train", "all")
         if not self.path.is_file():
             db_paths = sorted(self.path.glob("*.lmdb"))