dev

Author: davidhassell

cf/domain.py

@@ -737,7 +737,10 @@ def indices(self, *config, **kwargs):
 
         Metadata constructs are selected conditions are specified on
         their data. Indices for subspacing are then automatically
-        inferred from where the conditions are met.
+        inferred from where the conditions are met. If a condition is
+        a callable function then if is automateically replaced with
+        the result of calling that function with the Domain as its
+        only argument.
 
         Metadata constructs and the conditions on their data are
         defined by keyword parameters.
@@ -1092,7 +1095,10 @@ def subspace(self, *config, **kwargs):
 
         Subspacing by metadata selects metadata constructs and
         specifies conditions on their data. Indices for subspacing are
-        then automatically inferred from where the conditions are met.
+        then automatically inferred from where the conditions are
+        met. If a condition is a callable function then if is
+        automateically replaced with the result of calling that
+        function with the Domain as its only argument.
 
         Metadata constructs and the conditions on their data are defined
         by keyword parameters.

cf/field.py

@@ -5349,9 +5349,9 @@ def healpix_increase_refinement_level(self, refinement_level, quantity):
         [[72.875 72.875 72.875 72.875 73.375 73.375 73.375 73.375]]
 
         """
-        from .data.dask_utils import cf_healpix_increase_refinement_indices
         from .healpix import (
             _healpix_increase_refinement_level,
+            _healpix_increase_refinement_level_indices,
             healpix_max_refinement_level,
         )
 
@@ -5470,46 +5470,11 @@ def healpix_increase_refinement_level(self, refinement_level, quantity):
             f.del_construct(key)
 
         # Create the healpix_index coordinates for the new refinement
-        # level, and put them into the Field.
+        # level
         healpix_index = hp["healpix_index"]
-
-        # Save any cached data elements
-        data = healpix_index.data
-        cached = data._get_cached_elements().copy()
-
-        dx = data.to_dask_array(
-            _force_mask_hardness=False, _force_to_memory=False
-        )
-
-        # Set the data type to allow for the largest possible HEALPix
-        # index at the new refinement level
-        dtype = cfdm.integer_dtype(12 * (4**refinement_level) - 1)
-        if dx.dtype != dtype:
-            dx = dx.astype(dtype, copy=False)
-
-        # Each chunk is going to get larger by a factor of 'ncells'
-        chunks = [(np.array(dx.chunks[0]) * ncells).tolist()]
-
-        dx = dx.map_blocks(
-            cf_healpix_increase_refinement_indices,
-            chunks=tuple(chunks),
-            dtype=dtype,
-            meta=np.array((), dtype=dtype),
-            ncells=ncells,
+        _healpix_increase_refinement_level_indices(
+            healpix_index, ncells, refinement_level
         )
-
-        healpix_index.set_data(dx, copy=False)
-
-        # Set new cached data elements
-        data = healpix_index.data
-        if 0 in cached:
-            x = np.array(cached[0], dtype=dtype) * ncells
-            data._set_cached_elements({0: x, 1: x + 1})
-
-        if -1 in cached:
-            x = np.array(cached[-1], dtype=dtype) * ncells + (ncells - 1)
-            data._set_cached_elements({-1: x})
-
         hp_key = f.set_construct(healpix_index, axes=axis, copy=False)
 
         # Update the healpix Coordinate Reference
@@ -9221,7 +9186,10 @@ def indices(self, *config, **kwargs):
 
         Metadata constructs are selected by conditions specified on
         their data. Indices for subspacing are then automatically
-        inferred from where the conditions are met.
+        inferred from where the conditions are met. If a condition is
+        a callable function then if is automateically replaced with
+        the result of calling that function with the Field as its only
+        argument.
 
         The returned tuple of indices may be used to created a
         subspace by indexing the original field construct with them.
@@ -13406,10 +13374,13 @@ def subspace(self):
 
         **Subspacing by metadata**
 
-        Subspacing by metadata, signified by the use of round brackets,
-        selects metadata constructs and specifies conditions on their
-        data. Indices for subspacing are then automatically inferred from
-        where the conditions are met.
+        Subspacing by metadata, signified by the use of round
+        brackets, selects metadata constructs and specifies conditions
+        on their data. Indices for subspacing are then automatically
+        inferred from where the conditions are met. If a condition is
+        a callable function then if is automateically replaced with
+        the result of calling that function with the Field as its only
+        argument.
 
         Metadata constructs and the conditions on their data are defined
         by keyword parameters.

cf/healpix.py

@@ -227,6 +227,85 @@ def _healpix_increase_refinement_level(x, ncells, iaxis, quantity):
     x.set_data(dx, copy=False)
 
 
+def _healpix_increase_refinement_level_indices(
+    healpix_index, ncells, refinement_level
+):
+    """Increase the refinement level of HEALPix indices in-place.
+
+    K. Gorski, Eric Hivon, A. Banday, B. Wandelt, M. Bartelmann, et
+    al.. HEALPix: A Framework for High-Resolution Discretization and
+    Fast Analysis of Data Distributed on the Sphere. The Astrophysical
+    Journal, 2005, 622 (2), pp.759-771.
+    https://dx.doi.org/10.1086/427976
+
+    .. versionadded:: NEXTVERSION
+
+    .. seealso:: `cf.Field.healpix_increase_refinement_level`
+
+    :Parameters:
+
+        healpix_index: `Coordinate`
+            The HEALPix indices to be changed. It is assumed they use
+            the "nested" indexing scheme.
+
+        ncells: `int`
+            The number of cells at the new higher refinement level
+            which are contained in one cell at the original refinement
+            level.
+
+        refinement_level: `int`
+            The new higher refinement level.
+
+    :Returns:
+
+        `None`
+
+    """
+    from cfdm import integer_dtype
+
+    from .data.dask_utils import cf_healpix_increase_refinement_indices
+
+    # Save any cached data elements
+    cached = healpix_index.data._get_cached_elements().copy()
+
+    # Get the Dask array.
+    #
+    # `cf_healpix_increase_refinement_indices` has its own call to
+    # `cfdm_to_memory`, so we can set _force_to_memory=False.
+    dx = healpix_index.data.to_dask_array(
+        _force_mask_hardness=False, _force_to_memory=False
+    )
+
+    # Set the data type to allow for the largest possible HEALPix
+    # index at the new refinement level
+    dtype = integer_dtype(12 * (4**refinement_level) - 1)
+    if dx.dtype != dtype:
+        dx = dx.astype(dtype, copy=False)
+
+    # Each chunk is going to get larger by a factor of 'ncells'
+    chunks = [(np.array(dx.chunks[0]) * ncells).tolist()]
+
+    dx = dx.map_blocks(
+        cf_healpix_increase_refinement_indices,
+        chunks=tuple(chunks),
+        dtype=dtype,
+        meta=np.array((), dtype=dtype),
+        ncells=ncells,
+    )
+
+    healpix_index.set_data(dx, copy=False)
+
+    # Set new cached data elements
+    data = healpix_index.data
+    if 0 in cached:
+        x = np.array(cached[0], dtype=dtype) * ncells
+        data._set_cached_elements({0: x, 1: x + 1})
+
+    if -1 in cached:
+        x = np.array(cached[-1], dtype=dtype) * ncells + (ncells - 1)
+        data._set_cached_elements({-1: x})
+
+
 def _healpix_indexing_scheme(healpix_index, hp, new_indexing_scheme):
     """Change the indexing scheme of HEALPix indices in-place.
 

cf/mixin/fielddomain.py

@@ -332,8 +332,17 @@ def _indices(self, config, data_axes, ancillary_mask, kwargs):
                         f"defined by {identity!r}"
                     )
 
+            # If the condition is a callable function, then call it
+            # with 'self' as the only argument and replace the
+            # condition with the result.
             if callable(value):
-                value = value(self)
+                try:
+                    value = value(self)
+                except Exception as e:
+                    raise RuntimeError(
+                        f"Error encountered when calling condition "
+                        f"{identity}={value}: {e}"
+                    )
 
             if axes in parsed:
                 # The axes are the same as an existing key

cf/test/test_Domain.py

@@ -504,7 +504,7 @@ def test_Domain_create_healpix(self):
         self.assertEqual(len(d.coordinate_references()), 1)
 
         hp = d.dimension_coordinate()
-        self.assertEqual(hp.data._get_cached_elements(), {0: 0, -1: 11})
+        self.assertEqual(hp.data._get_cached_elements(), {0: 0, 1: 1, -1: 11})
         self.assertTrue(np.array_equal(hp, np.arange(12)))
 
         self.assertEqual(