Source code for torch.utils
# mypy: allow-untyped-defs
import os.path as _osp
import torch
from .throughput_benchmark import ThroughputBenchmark
from .cpp_backtrace import get_cpp_backtrace
from .backend_registration import rename_privateuse1_backend, generate_methods_for_privateuse1_backend
from . import deterministic
from . import collect_env
import weakref
import copyreg
[docs]def set_module(obj, mod):
"""
Set the module attribute on a python object for a given object for nicer printing
"""
if not isinstance(mod, str):
raise TypeError("The mod argument should be a string")
obj.__module__ = mod
if torch._running_with_deploy():
# not valid inside torch_deploy interpreter, no paths exists for frozen modules
cmake_prefix_path = None
else:
cmake_prefix_path = _osp.join(_osp.dirname(_osp.dirname(__file__)), 'share', 'cmake')
[docs]def swap_tensors(t1, t2):
"""
This function swaps the content of the two Tensor objects.
At a high level, this will make t1 have the content of t2 while preserving
its identity.
This will not work if t1 and t2 have different slots.
"""
# Ensure there are no weakrefs
if weakref.getweakrefs(t1):
raise RuntimeError("Cannot swap t1 because it has weakref associated with it")
if weakref.getweakrefs(t2):
raise RuntimeError("Cannot swap t2 because it has weakref associated with it")
t1_slots = set(copyreg._slotnames(t1.__class__)) # type: ignore[attr-defined]
t2_slots = set(copyreg._slotnames(t2.__class__)) # type: ignore[attr-defined]
if t1_slots != t2_slots:
raise RuntimeError("Cannot swap t1 and t2 if they have different slots")
def swap_attr(name):
tmp = getattr(t1, name)
setattr(t1, name, (getattr(t2, name)))
setattr(t2, name, tmp)
def error_pre_hook(grad_outputs):
raise RuntimeError("Trying to execute AccumulateGrad node that was poisoned by swap_tensors "
"this can happen when you try to run backward on a tensor that was swapped. "
"For a module m with `torch.__future__.set_swap_module_params_on_conversion(True)` "
"you should not change the device or dtype of the module (e.g. `m.cpu()` or `m.half()`) "
"between running forward and backward. To resolve this, please only change the "
"device/dtype before running forward (or after both forward and backward).")
def check_use_count(t, name='t1'):
use_count = t._use_count()
error_str = (f"Expected use_count of {name} to be 1 or 2 with an AccumulateGrad node but got {use_count} "
f"make sure you are not holding references to the tensor in other places.")
if use_count > 1:
if use_count == 2 and t.is_leaf:
accum_grad_node = torch.autograd.graph.get_gradient_edge(t).node
# Make sure that the accumulate_grad node was not lazy_init-ed by get_gradient_edge
if t._use_count() == 2:
accum_grad_node.register_prehook(error_pre_hook)
else:
raise RuntimeError(error_str)
else:
raise RuntimeError(error_str)
check_use_count(t1, 't1')
check_use_count(t2, 't2')
# Swap the types
# Note that this will fail if there are mismatched slots
swap_attr("__class__")
# Swap the dynamic attributes
swap_attr("__dict__")
# Swap the slots
for slot in t1_slots:
if hasattr(t1, slot) and hasattr(t2, slot):
swap_attr(slot)
elif hasattr(t1, slot):
setattr(t2, slot, (getattr(t1, slot)))
delattr(t1, slot)
elif hasattr(t2, slot):
setattr(t1, slot, (getattr(t2, slot)))
delattr(t2, slot)
# Swap the at::Tensor they point to
torch._C._swap_tensor_impl(t1, t2)