292     # Meta is a magic key: it is automatically generated for structured
338 # Structured kernel generation is only supported for certain key types;
345     # For now, ufunc dispatch keys coincide with structured keys
534     # Whether or not this out functions is a "structured kernel".  Structured
537     # the kernel.  Only out functions can be structured; other functions
539     # Every structured kernel must have at least an out and a functional
541     structured: bool
543     # Whether or not this non-out function is a structured kernel, defined
547     # Only valid for structured kernels.  Specifies alternative of what
548     # to inherit from when defining the meta class for the structured
553     # Structured kernels can declare elements as "precomputed". These elements
656         structured = e.pop("structured", False)
657         assert isinstance(structured, bool), f"not a bool: {structured}"
664             "namespace is not supported in structured delegate,"
676             "namespace is not supported in structured inherits,"
694         assert precomputed_dict is None or structured is True
752                     # Why is 'structured' included? External backends (e.g.
753                     # XLA) opt into which ops are structured independently
754                     # of which in-tree ops are structured
757                         structured=structured
776             # if a function is a structured delegate, deleting the dispatch
788         elif not structured and structured_delegate is None:
805                 cpp.name(func), structured=False, cpp_namespace=DEFAULT_KERNEL_NAMESPACE
862             assert structured, "ufunc must be structured"
874                     structured=True,
879             # Structured functions MUST have a dispatch table
930                 structured=structured,
958         assert not self.structured, (
959             "This function is structured, but there was "
963             "This function delegates to another structured out function, "
982         if self.structured:
984                 "Put structured field on the out= "
989             ), "device_guard: False is not respected by structured kernels"
993                 "on out= functions; did you mean structured?"
997             ), "device_guard: False is not respected by structured kernels"
1001             self.structured and self.structured_delegate
1002         ), "Cannot have both structured and structured_delegate on function"
1010                 self.structured
1011             ), "structured_inherits must also imply structured: True"
1082         return self.structured or self.structured_delegate is not None
1093 # A structured kernel is guaranteed to have a functional and out variant, and
1097 # actually annotated structured.  Test the structured boolean to see if it
1098 # actually is structured or not.
1107     def structured(self) -> bool:  member in NativeFunctionsGroup
1109         return self.out.structured
1120             if self.structured != f.part_of_structured_group:
1122                     "NativeFunctionsGroup constructed from structured and unstructured "
1138         if self.structured:
1139             # For now, structured composite kernels are not supported (need some
1204         # these don't count as structured for our purposes here
1226     # Whether or not the operator has a structured kernel implemented, for this particular backend.
1227     # For in-tree backends, they all have the same value for structured- this is listed
1229     # However, external backends like XLA can indendently toggle which ops are structured.
1230     structured: bool
1265 # External backends can choose to opt their kernels to be structured independently from in-tree bac…
1270 …# Mainly important for structured kernels, this determines which variant in the operator group is …