Fixing loaded_time_indices to support more advanced compute() functions

parcels/field.py

@@ -208,6 +208,7 @@ def __init__(
         else:
             raise ValueError("Unsupported mesh type. Choose either: 'spherical' or 'flat'")
         self.timestamps = timestamps
+        self._loaded_time_indices: Iterable[int] = []  # type: ignore
         if isinstance(interp_method, dict):
             if self.name in interp_method:
                 self.interp_method = interp_method[self.name]
@@ -265,6 +266,7 @@ def __init__(
 
         if not self.grid.defer_load:
             self.data = self._reshape(self.data, transpose)
+            self._loaded_time_indices = range(self.grid.tdim)
 
             # Hack around the fact that NaN and ridiculously large values
             # propagate in SciPy's interpolators
@@ -288,7 +290,6 @@ def __init__(
             self._dataFiles = np.append(self._dataFiles, self._dataFiles[0])
         self._field_fb_class = kwargs.pop("FieldFileBuffer", None)
         self._netcdf_engine = kwargs.pop("netcdf_engine", "netcdf4")
-        self._loaded_time_indices: Iterable[int] = []  # type: ignore
         self._creation_log = kwargs.pop("creation_log", "")
         self.chunksize = kwargs.pop("chunksize", None)
         self.netcdf_chunkdims_name_map = kwargs.pop("chunkdims_name_map", None)

parcels/fieldset.py

@@ -1538,6 +1538,7 @@ def computeTimeChunk(self, time=0.0, dt=1):
         for f in self.get_fields():
             if isinstance(f, (VectorField, NestedField)) or not f.grid.defer_load or f._dataFiles is None:
                 continue
+            f._loaded_time_indices = []  # reset loaded time indices
             g = f.grid
             if g._update_status == "first_updated":  # First load of data
                 if f.data is not None and not isinstance(f.data, DeferredArray):