rocm_jax/jax/_src/tree.py
2024-07-09 08:06:16 -07:00

287 lines
9.1 KiB
Python

# Copyright 2024 The JAX Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import annotations
from collections.abc import Callable, Iterable
from typing import Any, TypeVar, overload
from jax._src import tree_util
T = TypeVar("T")
def all(tree: Any, *, is_leaf: Callable[[Any], bool] | None = None) -> bool:
"""Call all() over the leaves of a tree.
Args:
tree: the pytree to evaluate
is_leaf : an optionally specified function that will be called at each
flattening step. It should return a boolean, which indicates whether the
flattening should traverse the current object, or if it should be stopped
immediately, with the whole subtree being treated as a leaf.
Returns:
result: boolean True or False
Examples:
>>> import jax
>>> jax.tree.all([True, {'a': True, 'b': (True, True)}])
True
>>> jax.tree.all([False, (True, False)])
False
See Also:
- :func:`jax.tree.reduce`
- :func:`jax.tree.leaves`
"""
return tree_util.tree_all(tree, is_leaf=is_leaf)
def flatten(tree: Any,
is_leaf: Callable[[Any], bool] | None = None
) -> tuple[list[tree_util.Leaf], tree_util.PyTreeDef]:
"""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.
Args:
tree: a pytree to flatten.
is_leaf: 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.
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.
Examples:
>>> import jax
>>> vals, treedef = jax.tree.flatten([1, (2, 3), [4, 5]])
>>> vals
[1, 2, 3, 4, 5]
>>> treedef
PyTreeDef([*, (*, *), [*, *]])
See Also:
- :func:`jax.tree.leaves`
- :func:`jax.tree.structure`
- :func:`jax.tree.unflatten`
"""
return tree_util.tree_flatten(tree, is_leaf)
def leaves(tree: Any,
is_leaf: Callable[[Any], bool] | None = None
) -> list[tree_util.Leaf]:
"""Gets the leaves of a pytree.
Args:
tree: the pytree for which to get the leaves
is_leaf : an optionally specified function that will be called at each
flattening step. It should return a boolean, which indicates whether the
flattening should traverse the current object, or if it should be stopped
immediately, with the whole subtree being treated as a leaf.
Returns:
leaves: a list of tree leaves.
Examples:
>>> import jax
>>> jax.tree.leaves([1, (2, 3), [4, 5]])
[1, 2, 3, 4, 5]
See Also:
- :func:`jax.tree.flatten`
- :func:`jax.tree.structure`
- :func:`jax.tree.unflatten`
"""
return tree_util.tree_leaves(tree, is_leaf)
def map(f: Callable[..., Any],
tree: Any,
*rest: Any,
is_leaf: Callable[[Any], bool] | None = None) -> Any:
"""Maps a multi-input function over pytree args to produce a new pytree.
Args:
f: function that takes ``1 + len(rest)`` arguments, to be applied at the
corresponding leaves of the pytrees.
tree: a pytree to be mapped over, with each leaf providing the first
positional argument to ``f``.
rest: a tuple of pytrees, each of which has the same structure as ``tree``
or has ``tree`` as a prefix.
is_leaf: an optionally specified function that will be called at each
flattening step. It should return a boolean, which indicates whether the
flattening should traverse the current object, or if it should be stopped
immediately, with the whole subtree being treated as a leaf.
Returns:
A new pytree with the same structure as ``tree`` but with the value at each
leaf given by ``f(x, *xs)`` where ``x`` is the value at the corresponding
leaf in ``tree`` and ``xs`` is the tuple of values at corresponding nodes in
``rest``.
Examples:
>>> import jax
>>> jax.tree.map(lambda x: x + 1, {"x": 7, "y": 42})
{'x': 8, 'y': 43}
If multiple inputs are passed, the structure of the tree is taken from the
first input; subsequent inputs need only have ``tree`` as a prefix:
>>> jax.tree.map(lambda x, y: [x] + y, [5, 6], [[7, 9], [1, 2]])
[[5, 7, 9], [6, 1, 2]]
See Also:
- :func:`jax.tree.leaves`
- :func:`jax.tree.reduce`
"""
return tree_util.tree_map(f, tree, *rest, is_leaf=is_leaf)
@overload
def reduce(function: Callable[[T, Any], T],
tree: Any,
*,
is_leaf: Callable[[Any], bool] | None = None) -> T:
...
@overload
def reduce(function: Callable[[T, Any], T],
tree: Any,
initializer: T,
is_leaf: Callable[[Any], bool] | None = None) -> T:
...
def reduce(function: Callable[[T, Any], T],
tree: Any,
initializer: Any = tree_util.no_initializer,
is_leaf: Callable[[Any], bool] | None = None) -> T:
"""Call reduce() over the leaves of a tree.
Args:
function: the reduction function
tree: the pytree to reduce over
initializer: the optional initial value
is_leaf : an optionally specified function that will be called at each
flattening step. It should return a boolean, which indicates whether the
flattening should traverse the current object, or if it should be stopped
immediately, with the whole subtree being treated as a leaf.
Returns:
result: the reduced value.
Examples:
>>> import jax
>>> import operator
>>> jax.tree.reduce(operator.add, [1, (2, 3), [4, 5, 6]])
21
See Also:
- :func:`jax.tree.leaves`
- :func:`jax.tree.map`
"""
return tree_util.tree_reduce(function, tree, initializer, is_leaf=is_leaf)
def structure(tree: Any,
is_leaf: None | (Callable[[Any], bool]) = None) -> tree_util.PyTreeDef:
"""Gets the treedef for a pytree.
Args:
tree: the pytree for which to get the leaves
is_leaf : an optionally specified function that will be called at each
flattening step. It should return a boolean, which indicates whether the
flattening should traverse the current object, or if it should be stopped
immediately, with the whole subtree being treated as a leaf.
Returns:
pytreedef: a PyTreeDef representing the structure of the tree.
Examples:
>>> import jax
>>> jax.tree.structure([1, (2, 3), [4, 5]])
PyTreeDef([*, (*, *), [*, *]])
See Also:
- :func:`jax.tree.flatten`
- :func:`jax.tree.leaves`
- :func:`jax.tree.unflatten`
"""
return tree_util.tree_structure(tree, is_leaf)
def transpose(outer_treedef: tree_util.PyTreeDef,
inner_treedef: tree_util.PyTreeDef | None,
pytree_to_transpose: Any) -> Any:
"""Transform a tree having tree structure (outer, inner) into one having structure (inner, outer).
Args:
outer_treedef: PyTreeDef representing the outer tree.
inner_treedef: PyTreeDef representing the inner tree.
If None, then it will be inferred from outer_treedef and the structure of
pytree_to_transpose.
pytree_to_transpose: the pytree to be transposed.
Returns:
transposed_pytree: the transposed pytree.
Examples:
>>> import jax
>>> tree = [(1, 2, 3), (4, 5, 6)]
>>> inner_structure = jax.tree.structure(('*', '*', '*'))
>>> outer_structure = jax.tree.structure(['*', '*'])
>>> jax.tree.transpose(outer_structure, inner_structure, tree)
([1, 4], [2, 5], [3, 6])
Inferring the inner structure:
>>> jax.tree.transpose(outer_structure, None, tree)
([1, 4], [2, 5], [3, 6])
"""
return tree_util.tree_transpose(outer_treedef, inner_treedef, pytree_to_transpose)
def unflatten(treedef: tree_util.PyTreeDef,
leaves: Iterable[tree_util.Leaf]) -> Any:
"""Reconstructs a pytree from the treedef and the leaves.
The inverse of :func:`tree_flatten`.
Args:
treedef: the treedef to reconstruct
leaves: the iterable of leaves to use for reconstruction. The iterable must
match the leaves of the treedef.
Returns:
The reconstructed pytree, containing the ``leaves`` placed in the structure
described by ``treedef``.
Examples:
>>> import jax
>>> vals, treedef = jax.tree.flatten([1, (2, 3), [4, 5]])
>>> newvals = [100, 200, 300, 400, 500]
>>> jax.tree.unflatten(treedef, newvals)
[100, (200, 300), [400, 500]]
See Also:
- :func:`jax.tree.flatten`
- :func:`jax.tree.leaves`
- :func:`jax.tree.structure`
"""
return tree_util.tree_unflatten(treedef, leaves)