jax.tree_util.tree_flatten#
- jax.tree_util.tree_flatten(tree, is_leaf=None)[source]#
Flattens a pytree.
The flattening order (i.e. the order of elements in the output list) is deterministic, corresponding to a left-to-right depth-first tree traversal.
- Parameters:
tree (Any) – a pytree to flatten.
is_leaf (Callable[[Any], bool] | None) – an optionally specified function that will be called at each flattening step. It should return a boolean, with true stopping the traversal and the whole subtree being treated as a leaf, and false indicating the flattening should traverse the current object.
- Return type:
tuple[list[Leaf], PyTreeDef]
- Returns:
A pair where the first element is a list of leaf values and the second element is a treedef representing the structure of the flattened tree.
Example
>>> import jax >>> vals, treedef = jax.tree.flatten([1, (2, 3), [4, 5]]) >>> vals [1, 2, 3, 4, 5] >>> treedef PyTreeDef([*, (*, *), [*, *]])