2025-08-11 12:24:21 +08:00

232 lines
8.4 KiB
Python

# Copyright 2021 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 typing import Any, TYPE_CHECKING
from jax._src.lib import jaxlib_extension_version
from jax._src.lib import _jax
from jax._src.util import use_cpp_class, use_cpp_method, set_module
export = set_module('jax.sharding')
# TODO(phawkins): the union confuses pytype. Just use the Python branch for now
# until the C++ version is the minimum version.
if not TYPE_CHECKING and jaxlib_extension_version >= 352:
_UNCONSTRAINED_PARTITION = _jax.UNCONSTRAINED_PARTITION
_canonicalize_partition = _jax.canonicalize_partition
else:
class UnconstrainedSingleton:
def __repr__(self):
return "UNCONSTRAINED"
def __reduce__(self):
return (_get_default_unconstrained, ())
# Unconstrained sentinel value for PartitionSpec, representing a dimension for
# which the user wants XLA to assign the best partitioning.
# TODO(yashkatariya): May rename to AUTO.
_UNCONSTRAINED_PARTITION = UnconstrainedSingleton()
def _get_default_unconstrained():
return _UNCONSTRAINED_PARTITION
def _canonicalize_partition(partition):
if not partition:
return None
if partition is _UNCONSTRAINED_PARTITION:
return _UNCONSTRAINED_PARTITION
if isinstance(partition, (tuple, list)):
if len(partition) == 1:
return partition[0]
return tuple(partition)
return partition
def _check(partitions, unreduced, reduced):
for p in partitions:
p = p if isinstance(p, tuple) else (p,)
for r in p:
if r in unreduced:
raise ValueError(
"partitions cannot overlap with unreduced axes passed to"
f" PartitionSpec. Got partitions: {partitions} and unreduced axes:"
f" {unreduced}")
if r in reduced:
raise ValueError(
"partitions cannot overlap with reduced axes passed to"
f" PartitionSpec. Got partitions: {partitions} and reduced axes:"
f" {reduced}")
if unreduced & reduced:
raise ValueError(
"`unreduced` and `reduced` argument to PartitionSpec cannot overlap. "
f"Got {unreduced=}, {reduced=}")
if None in unreduced:
raise ValueError(
"unreduced cannot contain None. All elements in unreduced should refer"
" to the mesh axes.")
if None in reduced:
raise ValueError(
"reduced cannot contain None. All elements in reduced should refer"
" to the mesh axes.")
def unpickle_pspec(partitions, unreduced, reduced):
return PartitionSpec(*partitions, unreduced=unreduced, reduced=reduced)
def _get_ur_str(unreduced, reduced):
if unreduced and reduced:
return f"unreduced={set(unreduced)!r}, reduced={set(reduced)!r}"
elif unreduced and not reduced:
return f"unreduced={set(unreduced)!r}"
elif not unreduced and reduced:
return f"reduced={set(reduced)!r}"
assert False # unreachable
AxisName = Any
class PartitionSpec:
"""Tuple describing how to partition an array across a mesh of devices.
Each element is either ``None``, a string, or a tuple of strings.
See the documentation of :class:`jax.sharding.NamedSharding` for more details.
This class exists so JAX's pytree utilities can distinguish a partition
specifications from tuples that should be treated as pytrees.
"""
if jaxlib_extension_version < 352:
__slots__ = ("_partitions", "unreduced", "reduced")
__match_args__ = ("_partitions",)
# A sentinel value representing a dim is unconstrained.
UNCONSTRAINED = _UNCONSTRAINED_PARTITION
@use_cpp_method()
def __init__(self, *partitions, unreduced=frozenset(), reduced=frozenset()):
self._partitions = tuple(_canonicalize_partition(p) for p in partitions)
if not isinstance(unreduced, (set, frozenset)):
raise TypeError(
"`unreduced` argument of PartitionSpec should be of type"
f" `frozenset` or `set`. Got type {type(unreduced)}")
if not isinstance(reduced, (set, frozenset)):
raise TypeError(
"`reduced` argument of PartitionSpec should be of type"
f" `frozenset` or `set`. Got type {type(reduced)}")
self.unreduced = frozenset(unreduced)
self.reduced = frozenset(reduced)
_check(self._partitions, self.unreduced, self.reduced)
def __repr__(self):
pr = repr(self._partitions)[1:-1]
if not self.unreduced and not self.reduced:
return f"PartitionSpec({pr})"
ur_str = _get_ur_str(self.unreduced, self.reduced)
pr = '' if not pr else f"{pr} " if pr.endswith(',') else f"{pr}, "
return (f"PartitionSpec({pr}{ur_str})")
def __reduce__(self):
return (unpickle_pspec, (self._partitions, self.unreduced, self.reduced))
def __getitem__(self, i):
return self._partitions[i]
def __iter__(self):
return iter(self._partitions)
def __len__(self):
return len(self._partitions)
@use_cpp_method()
def __eq__(self, other):
if isinstance(other, PartitionSpec):
return (self._partitions == other._partitions and
self.unreduced == other.unreduced and
self.reduced == other.reduced)
elif isinstance(other, tuple):
if self.unreduced:
raise TypeError(
f"other {other} cannot be of instance `tuple` when self {self} has"
" unreduced in `__eq__` of PartitionSpec.")
if self.reduced:
raise TypeError(
f"other {other} cannot be of instance `tuple` when self {self} has"
" reduced in `__eq__` of PartitionSpec.")
other_p = tuple(_canonicalize_partition(o) for o in other)
return self._partitions == other_p
else:
return False
@use_cpp_method()
def __hash__(self):
return hash((self._partitions, self.unreduced, self.reduced))
def __add__(self, other):
if isinstance(other, PartitionSpec):
return PartitionSpec(
*self, *other,
unreduced={*self.unreduced, *other.unreduced},
reduced={*self.reduced, *other.reduced})
elif isinstance(other, tuple):
if self.unreduced:
raise TypeError(
f"other {other} cannot be of instance `tuple` when self {self} has"
" unreduced in `__add__` of PartitionSpec.")
if self.reduced:
raise TypeError(
f"other {other} cannot be of instance `tuple` when self {self} has"
" reduced in `__add__` of PartitionSpec.")
return PartitionSpec(*self, *other)
else:
raise NotImplementedError
def __radd__(self, other):
if not isinstance(other, tuple):
raise NotImplementedError
# other will always be a tuple.
if self.unreduced:
raise TypeError(
f"other {other} cannot be of instance `tuple` when self {self} has"
" unreduced in `__radd__` of PartitionSpec.")
if self.reduced:
raise TypeError(
f"other {other} cannot be of instance `tuple` when self {self} has"
" reduced in `__radd__` of PartitionSpec.")
return PartitionSpec(*other, *self)
def index(self, value):
return self._partitions.index(_canonicalize_partition(value))
def count(self, value):
return self._partitions.count(_canonicalize_partition(value))
def update(self, **kwargs):
return PartitionSpec(*kwargs.pop("partitions", self._partitions),
unreduced=kwargs.pop("unreduced", self.unreduced),
reduced=kwargs.pop("reduced", self.reduced))
def _normalized_spec_for_aval(self, ndim: int) -> PartitionSpec:
out = [None if p is _UNCONSTRAINED_PARTITION else p
for p in self._partitions]
if len(out) < ndim:
out.extend([None] * (ndim - len(out)))
return self.update(partitions=out)
# TODO(phawkins): make this a decorator after the next jaxlib release.
if not TYPE_CHECKING and jaxlib_extension_version >= 352:
PartitionSpec = use_cpp_class(_jax.PartitionSpec)(PartitionSpec)
# TODO(phawkins): make this a decorator after the next jaxlib release.
if not TYPE_CHECKING:
PartitionSpec = export(PartitionSpec)