jax.tree.flatten_with_path#

jax.tree.flatten_with_path(tree, is_leaf=None)[source]#

Flattens a pytree like tree_flatten, but also returns each leaf’s key path.

Parameters:

  • tree (Any) – a pytree to flatten. If it contains a custom type, it is recommended to be registered with register_pytree_with_keys.

  • is_leaf (Callable[[Any], bool] | None | None)

Returns:

A pair which the first element is a list of key-leaf pairs, each of which contains a leaf and its key path. The second element is a treedef representing the structure of the flattened tree.

Return type:

tuple[list[tuple[tree_util.KeyPath, Any]], tree_util.PyTreeDef]

Examples

>>> import jax
>>> path_vals, treedef = jax.tree.flatten_with_path([1, {'x': 3}])
>>> path_vals
[((SequenceKey(idx=0),), 1), ((SequenceKey(idx=1), DictKey(key='x')), 3)]
>>> treedef
PyTreeDef([*, {'x': *}])

See also