Use individual and combined callbacks for CombinedDrive

micromagneticdata/abstract_drive.py

@@ -177,6 +177,7 @@ def n(self):
     def _step_files(self):
         """List of filenames of individual snapshots."""
 
+    @abc.abstractmethod
     def __getitem__(self, item):
         """Magnetisation field of an individual step.
 
@@ -200,10 +201,6 @@ def __getitem__(self, item):
         Field(...)
 
         """
-        field = df.Field.fromfile(filename=self._step_files[item])
-        with contextlib.suppress(FileNotFoundError):
-            field.mesh.load_subregions(self._m0_path)
-        return self._apply_callbacks(field)
 
     def __iter__(self):
         """Iterator.

micromagneticdata/combined_drive.py

@@ -1,4 +1,5 @@
 import functools
+import numbers
 import operator
 
 import ubermagutil as uu
@@ -140,6 +141,16 @@ def table(self):
     def _step_files(self):
         return sum((drive._step_files for drive in self.drives), start=[])
 
+    def __getitem__(self, item):
+        if not isinstance(item, numbers.Integral):
+            raise TypeError(f"{type(item)=} is not supported")
+        if item >= self.n or item < -self.n:
+            raise IndexError("List index out of range.")
+        for drive in self.drives:
+            if item < drive.n:
+                return self._apply_callbacks(drive[item])
+            item -= drive.n
+
     def __lshift__(self, other):
         if isinstance(other, md.Drive):
             return self.__class__(*self.drives, other)

micromagneticdata/drive.py

@@ -1,4 +1,5 @@
 import abc
+import contextlib
 import copy
 import json
 import numbers
@@ -212,7 +213,10 @@ def __getitem__(self, item):
 
         """
         if isinstance(item, numbers.Integral):
-            return super().__getitem__(item)
+            field = df.Field.fromfile(filename=self._step_files[item])
+            with contextlib.suppress(FileNotFoundError):
+                field.mesh.load_subregions(self._m0_path)
+            return self._apply_callbacks(field)
         elif isinstance(item, slice):
             step_files = self._step_files[item]
             table = copy.copy(self.table)