_pytree.py 1.8 KB

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  1. from typing import Callable, Any, Tuple, List, Dict, Type, NamedTuple
  2. from torch.utils._pytree import PyTree, TreeSpec, LeafSpec
  3. from collections import namedtuple
  4. FlattenFuncSpec = Callable[[PyTree, TreeSpec], List]
  5. SUPPORTED_NODES: Dict[Type[Any], Any] = {}
  6. def register_pytree_flatten_spec(typ: Any, flatten_fn_spec: FlattenFuncSpec) -> None:
  7. SUPPORTED_NODES[typ] = flatten_fn_spec
  8. def tree_flatten_spec(pytree: PyTree, spec: TreeSpec) -> List[Any]:
  9. if isinstance(spec, LeafSpec):
  10. return [pytree]
  11. if spec.type not in SUPPORTED_NODES:
  12. raise RuntimeError(
  13. f"{type(pytree)} does not have a flatten_fn_spec associated with it. Please register one with"
  14. "torch.fx._pytree.register_pytree_flatten_spec. If you have serialized your model, make"
  15. "sure that any custom pytrees have been registered before loading it.")
  16. flatten_fn_spec = SUPPORTED_NODES[spec.type]
  17. child_pytrees = flatten_fn_spec(pytree, spec)
  18. result = []
  19. for child, child_spec in zip(child_pytrees, spec.children_specs):
  20. flat = tree_flatten_spec(child, child_spec)
  21. result += flat
  22. return result
  23. def _dict_flatten_spec(d: Dict[Any, Any], spec: TreeSpec) -> List[Any]:
  24. return [d[k] for k in spec.context]
  25. def _list_flatten_spec(d: List[Any], spec: TreeSpec) -> List[Any]:
  26. return [d[i] for i in range(len(spec.children_specs))]
  27. def _tuple_flatten_spec(d: Tuple[Any], spec: TreeSpec) -> List[Any]:
  28. return [d[i] for i in range(len(spec.children_specs))]
  29. def _namedtuple_flatten_spec(d: NamedTuple, spec: TreeSpec) -> List[Any]:
  30. return [d[i] for i in range(len(spec.children_specs))]
  31. register_pytree_flatten_spec(dict, _dict_flatten_spec)
  32. register_pytree_flatten_spec(list, _list_flatten_spec)
  33. register_pytree_flatten_spec(tuple, _tuple_flatten_spec)
  34. register_pytree_flatten_spec(namedtuple, _tuple_flatten_spec)