Adapt XArrayField to changes in earthkit-data Field : Merge pull requ…

…est #138 from ecmwf/feature/adapt-xarray-fields-to-earthkit-data-changes

Adapt XArrayField to changes in earthkit-data Field

src/anemoi/datasets/create/functions/sources/xarray/field.py

@@ -10,6 +10,7 @@
 
 import datetime
 import logging
+from functools import cached_property
 
 from earthkit.data.core.fieldlist import Field
 from earthkit.data.core.fieldlist import math
@@ -46,8 +47,6 @@ def __init__(self, owner, selection):
             This is actually a nD object, but the first dimensions are always 1.
             The other two dimensions are latitude and longitude.
         """
-        super().__init__(owner.array_backend)
-
         self.owner = owner
         self.selection = selection
 
@@ -86,7 +85,8 @@ def to_numpy(self, flatten=False, dtype=None, index=None):
 
         return values  # .reshape(self.shape)
 
-    def _make_metadata(self):
+    @cached_property
+    def _metadata(self):
         return XArrayMetadata(self)
 
     def grid_points(self):

src/anemoi/datasets/create/functions/sources/xarray/variable.py

@@ -13,7 +13,6 @@
 from functools import cached_property
 
 import numpy as np
-from earthkit.data.utils.array import ensure_backend
 
 from .field import XArrayField
 
@@ -30,7 +29,6 @@ def __init__(
         grid,
         time,
         metadata,
-        array_backend=None,
     ):
         self.ds = ds
         self.variable = variable
@@ -48,7 +46,6 @@ def __init__(
         self.by_name = {c.variable.name: c for c in coordinates}
 
         self.length = math.prod(self.shape)
-        self.array_backend = ensure_backend(array_backend)
 
     @property
     def name(self):