fix: Restore access to HDF5 file

src/eddymotion/data/dmri.py

@@ -70,6 +70,10 @@ class DWI:
     )
     """A path to an HDF5 file to store the whole dataset."""
 
+    def get_filename(self):
+        """Get the filepath of the HDF5 file."""
+        return self._filepath
+
     def __len__(self):
         """Obtain the number of high-*b* orientations."""
         return self.dataobj.shape[-1]

src/eddymotion/data/splitting.py

@@ -21,7 +21,9 @@
 #     https://www.nipreps.org/community/licensing/
 #
 """Data splitting helpers."""
+from pathlib import Path
 import numpy as np
+import h5py
 
 
 def lovo_split(data, index):
@@ -46,14 +48,23 @@ def lovo_split(data, index):
 
     """
 
+    if not Path(data.get_filename()).exists():
+        data.to_filename(data.get_filename())
+
     # if the size of the mask does not match data, cache is stale
     mask = np.zeros(len(data), dtype=bool)
     mask[index] = True
 
+    # read original DWI data & b-vector
+    with h5py.File(data.get_filename(), "r") as in_file:
+        root = in_file["/0"]
+        dwframe = np.asanyarray(root["dataobj"][..., mask])
+        bframe = np.asanyarray(root["gradients"][..., mask])
+
     train_data = data.dataobj[..., ~mask]
     train_gradients = data.gradients[..., ~mask]
 
     return (
         (train_data, train_gradients),
-        (data.dataobj[..., mask], data.gradients[..., mask]),
+        (dwframe, bframe),
     )