feat: add hiopy::var_group attribute to split up variable groups into

multipole components

apps/hiopy/_grids.py

@@ -10,9 +10,11 @@ def grid_id(var, zgroup):
     assert "grid_mapping" in var.attrs
     crs = zgroup[var.attrs["grid_mapping"]]
 
+    var_group = var.attrs.get("hiopy::var_group", "")
+
     # healpix
     if "grid_mapping_name" in crs.attrs and crs.attrs["grid_mapping_name"] == "healpix":
-        s = "healpix_"
+        s = var_group + "healpix_"
         s += str(crs.attrs["healpix_nside"])
         s += str(crs.attrs["healpix_order"])
         if "_ARRAY_DIMENSIONS" in var.attrs and var.attrs["_ARRAY_DIMENSIONS"][-1] in zgroup:
@@ -23,7 +25,7 @@ def grid_id(var, zgroup):
     if "coordinates" in crs.attrs:
         try:
             lon, lat = crs.attrs["coordinates"].split(" ")
-            s = hash(hash(str(zgroup[lat][:])) + hash(str(zgroup[lon][:])))
+            s = hash(hash(str(zgroup[lat][:])) + hash(str(zgroup[lon][:])) + var_group)
             return s
         except Exception as e:
             raise RuntimeError("Cannot parse coordinates") from e

doc/hiopy.rst

@@ -95,6 +95,7 @@ hiopy specific parameters are added in the attributes and are usually prefixed b
    "hiopy::nnn", "Array", "Number of nearest neighbors to use. Default is 1."
    "hiopy::frac_mask", "Array", "Array name of the fractional mask that is used when forwarding the data. (see `yac_cput_frac`)"
    "hiopy::enable", "Boolean", "Enable or disable the variable to be handled by the worker"
+   "hiopy::var_group", "Array", "Can be used to split-up variables into multiple groups, if not enough chunks are available to distribute the work (optional)."
 
 `hiopy.configure` can also be used as a python
 module.  The following example creates a dataset with healpix grid