A proposal addressing Issue #1489: **Optimizer should track parameter names and not id.**
(also mentioned in here: [[RFC] Introducing FQNs/clarity eyeglasses to optim state_dict](https://dev-discuss.pytorch.org/t/rfc-introducing-fqns-clarity-to-optim-state-dict/1552)
## Summary
This PR introduces a backward-compatible enhancement where optimizers track parameter names instead of just their id.
Optimizers can be initialized with `named_parameters()` as:
```python
optimizer = optim.SGD(model.named_parameters(), lr=0.01, momentum=0.9)
```
This allows for greater clarity and ease when handling optimizers, as the parameters' names are preserved within the optimizer’s `state_dict` as:
```
state_dict =
{
'state': {
0: {'momentum_buffer': tensor(...), ...},
1: {'momentum_buffer': tensor(...), ...},
},
'param_groups': [
{
'lr': 0.01,
'weight_decay': 0,
...
'params': [0,1]
'param_names' ['layer.weight', 'layer.bias'] (optional)
}
]
}
```
Loading `state_dict` is not changed (backward-compatible) and the `param_names` key will be ignored.
## Key Features
#### Named Parameters in Optimizer Initialization:
Optimizers can accept the output of `model.named_parameters()` during initialization, allowing them to store parameter names directly.
#### Parameter Names in `state_dict`:
The parameter names are saved as a list in the optimizer’s `state_dict` with key `param_names`, alongside the `params` indices, ensuring seamless tracking of both names and parameters.
## Backward Compatibility
#### No Breaking Changes:
This change is fully backward-compatible. The added `param_names` key in the optimizer's `state_dict` is ignored when loading a state to the optimizer.
#### Customization with Hooks:
For more control, the loaded state_dict can be modified using a custom `register_load_state_dict_pre_hook`, providing flexibility for different design needs.
## Documentation Updates
Please refer to the documentation changes for more details on how this feature is implemented and how it can be used effectively.
## Solution Example:
A suggested solution to the problem mentioned in #1489, for the same parameters but in a different order.
The following `register_load_state_dict_pre_hook` should be added to the optimizer before loading to enable loading the state dict :
```python
def adapt_state_dict_ids(optimizer, state_dict):
# assuming a single param group.
current_state_group = optimizer.state_dict()['param_groups'][0]
loaded_state_group = state_dict['param_groups'][0]
# same number of params, same names, only different ordering
current_state_name_to_id_mapping = {} # mapping -- param_name: id
for i, name in enumerate(current_state_group['param_names']):
current_state_name_to_id_mapping[name] = current_state_group['params'][i]
# changing the ids of the loaded state dict to match the order of the given state dict.
for i, name in enumerate(current_state_group['param_names']):
loaded_state_group['params'][i] = current_state_name_to_id_mapping[name]
return state_dict
```
In this code, the loaded `state_dict` ids are adapted to match the order of the current optimizer `state_dict`.
Both the previous and the current optimizers are required to be initiated with `named_parameters()` to have the 'param_names' key in the dict.
### Note
This is my first contribution to PyTorch, and I wish to receive feedback or suggestions for improvement.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/134107
Approved by: https://github.com/janeyx99
Co-authored-by: Jane (Yuan) Xu <31798555+janeyx99@users.noreply.github.com>
When stub files (`*.pyi`) were removed from `optim` (#125556, #125452), some types that existed are no longer available. This pull request adds them back.
Just for reference, these types are used in `pytorch-lightning`'s `LightningCLI`. Command line interfaces are created automatically, and having type hints make them nicer.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/136185
Approved by: https://github.com/janeyx99
Link various classes and functions of the `optim.swa.util` to make doc content accessible from the `torch.optim` doc.
Currently, if you click the link,
https://pytorch.org/docs/stable/optim.html#module-torch.optim.swa_utils it goes to a blank, bottom of the page section of `torch.optim`.
Also,
`torch.optim.swa_utils.AveragedModel` and `torch.optim.swa_utils.SWALR` classes as well as `torch.optim.swa_utils.update_bn()` and `optim.swa_utils.get_ema_multi_avg_fn` are not linked to doc.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/133393
Approved by: https://github.com/janeyx99
There could be some cases where the params have the meta device when calling optimizer's dunder init and those params are materialized in the first computation. This change would allow such situation.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131153
Approved by: https://github.com/mlazos, https://github.com/janeyx99
Co-authored-by: Jane (Yuan) Xu <31798555+janeyx99@users.noreply.github.com>
This PR adds the foreach impl for Adafactor knowing that there are many ways to improve its runtime perf today (by adding more foreach support). After this PR:
- we have a foreach flag for Adafactor
- It is NOT the default. Why not? It is only slightly faster + uses O(n) more memory where n is the number of params in your max param group. People tend to use Adafactor for memory efficiency.
Next steps:
- make torch.compile possible on it
- make it faster (by adding more foreach apis)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/132336
Approved by: https://github.com/albanD
ghstack dependencies: #133360
This PR fixes a bug in `test_correct_module_names` introduced in #130497. It also addresses post-fix test failures in:
* `torch/ao/quantization/__init__.py` - set the correct `__module__` for several public API helpers
* `torch/library.py` - add `register_vmap` to `__all__`
* `torch/nn/attention/flex_attention.py` - make `round_up_to_multiple` private by prepending an underscore
* `torch/storage.py` - introduce `__all__` to avoid `Self` being re-exported as a public API
* `torch/distributed/pipelining/schedules.py` - add `ZeroBubbleAlgorithm` to `__all__`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131386
Approved by: https://github.com/albanD
This PR fixes a bug in `test_correct_module_names` introduced in #130497. It also addresses post-fix test failures in:
* `torch/ao/quantization/__init__.py` - set the correct `__module__` for several public API helpers
* `torch/library.py` - add `register_vmap` to `__all__`
* `torch/nn/attention/flex_attention.py` - make `round_up_to_multiple` private by prepending an underscore
* `torch/storage.py` - introduce `__all__` to avoid `Self` being re-exported as a public API
* `torch/distributed/pipelining/schedules.py` - add `ZeroBubbleAlgorithm` to `__all__`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131386
Approved by: https://github.com/albanD
#109581
At this point, the vanilla implementation (the default) is good.
Docs: https://docs-preview.pytorch.org/pytorch/pytorch/129905/generated/torch.optim.Adafactor.html#torch.optim.Adafactor
Specifically, the impl in this PR, which attempts to replicate the paper,
```
optim = torch.optim.Adafactor([weight])
```
is close enough to https://pytorch-optimizers.readthedocs.io/en/latest/optimizer/#pytorch_optimizer.AdaFactor
```
optim_c = AdaFactor([weight], betas=(0, 0.999), scale_parameter=False)
```
is close enough to https://www.tensorflow.org/api_docs/python/tf/keras/optimizers/Adafactor
```
optim = keras.optimizers.Adafactor(learning_rate=0.01)
```
The three results respectively for the same randomly generated weights:
```
# ours
tensor([[ 0.3807594, -0.3912092],
[ 0.0762539, 0.5377805],
[ 0.2459473, 0.4662207]])
# pytorch-optimizer
tensor([[ 0.3807592, -0.3912172],
[ 0.0762507, 0.5377818],
[ 0.2459457, 0.4662213]])
# keras
array([[ 0.38076326, -0.39121315],
[ 0.0762547 , 0.5377859 ],
[ 0.24594972, 0.46622536]], dtype=float32)
```
This gives me confidence to move forward in speeding up the implementation now that a baseline has been established. If you're curious about differences:
* keras assigns step_size (rho_t in their code) to `min(lr, 1 / sqrt(step)` whereas the OG impl uses a hardcoded 0.01 instead of lr. We do the same thing as keras, but our lr default is 0.01.
* We differ from the pytorch-optimizers default in that our default will not track momentum (thus `beta1=0`) and we do not apply parameter scaling.
<details>
Keras collab: https://colab.research.google.com/drive/1i3xF8ChL7TWKJGV_5v_5nMhXKnYmQQ06?usp=sharing
My script repro:
```
import torch
from pytorch_optimizer import AdaFactor
torch.set_printoptions(precision=7)
weight = torch.tensor([[ 0.37697506, -0.39500135],
[ 0.07246649, 0.53399765],
[ 0.24216151, 0.46243715]], dtype=torch.float32)
# bias = torch.tensor([0, 0], dtype=torch.float32)
weight.grad = torch.tensor([[-0.5940447, -0.7743838],
[-0.5940447, -0.7743838],
[-0.5940447, -0.7743838]], dtype=torch.float32)
# bias.grad = torch.tensor([-2.5027974, 1.5422692], dtype=torch.float32)
weight_c = weight.clone()
weight_c.grad = weight.grad.clone()
optim = torch.optim.Adafactor([weight])
optim.step()
print(weight)
optim_c = AdaFactor([weight_c], betas=(0, 0.999), scale_parameter=False)
optim_c.step()
print(weight_c)
```
<details>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/129905
Approved by: https://github.com/albanD
Fix docstrings in Learning Rate Scheduler.
The fix can be verified by running pydocstyle path-to-file --count
Related #112593
**BEFORE the PR:**
pydocstyle torch/optim/lr_scheduler.py --count
92
**AFTER the PR:**
pydocstyle torch/optim/lr_scheduler.py --count
0
Pull Request resolved: https://github.com/pytorch/pytorch/pull/128679
Approved by: https://github.com/janeyx99
I'm currently locked into jsonargparse version 4.19.0, and it complains when used in combination with LightningCLI (v2.0.8). This is because it cares about the types declared in google style docstrings. This causes a problem when it tries to parse how it should cast arguments to construct an instance of an LRScheduler class because the docstrings declare the "verbose" parameter as a bool, but the defaults recently changed to a string "deprecated". This means the type should really be `bool | str`.
This PR adds a `| str` to the docstring type in each learning rate scheduler class. This will prevent jsonargparse from complaining.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/127943
Approved by: https://github.com/janeyx99
Use `typing_extensions.deprecated` for deprecation annotation if possible. Otherwise, add `category=FutureWarning` to `warnings.warn("message")` if the category is missing.
Note that only warnings that their messages contain `[Dd]eprecat(ed|ion)` are updated in this PR.
UPDATE: Use `FutureWarning` instead of `DeprecationWarning`.
Resolves#126888
- #126888
Pull Request resolved: https://github.com/pytorch/pytorch/pull/126898
Approved by: https://github.com/albanD
The `usort` config in `pyproject.toml` has no effect due to a typo. Fixing the typo make `usort` do more and generate the changes in the PR. Except `pyproject.toml`, all changes are generated by `lintrunner -a --take UFMT --all-files`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/127122
Approved by: https://github.com/kit1980
This continues the full deprecation after https://github.com/pytorch/pytorch/pull/114425. It's been 6 months! And I'm fairly certain no one is going to yell at me as this patch is not really used.
------
# BC Breaking note
As of this PR, SparseAdam will become consistent with the rest of our optimizers in that it will only accept containers of Tensors/Parameters/param groups and fully complete deprecation of this path. Hitherto, the SparseAdam constructor had allowed raw tensors as the params argument to the constructor. Now, if you write the following code, there will be an error similar to every other optim: "params argument given to the optimizer should be an iterable of Tensors or dicts"
```
import torch
param = torch.rand(16, 32)
optimizer = torch.optim.SparseAdam(param)
```
Instead you should replace the last line with
```
optimizer = torch.optim.SparseAdam([param])
```
to no longer error.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/127081
Approved by: https://github.com/soulitzer
> previous: Originally, the variables `new_eta` and `new_mu` would be constructed `len(grouped_mus)` times, but each of their values is the same and won't be changed. Therefore, it can be simplified using Python list multiplication, which only constructs one tensor.
- [X] Ill assumption that every param will have the same step.
- [x] DIfferent implementation between `foreach=Ture` and `foreach=False`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/125440
Approved by: https://github.com/janeyx99
Since we now will support `capturable=False` when it's valid, narrow the eager fallback conditions to the cases where `compile` will fail. The lone case here is when the user deletes the capturable flag; `state_steps` are on cuda and `capturable` is `False`. Because a cuda tensor is not supported in the `value` kwarg for foreach ops this results in an error.
The fallback wrapper is changed to check the device of `state_steps` if `capturable=False`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/125825
Approved by: https://github.com/janeyx99
Add the missing documentation for `initial_accumulator_value` parameter in Adagrad, and update the algorithm description in the documentation (adjusted to reflect the implementation).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/125886
Approved by: https://github.com/janeyx99
Enables LRScheduler to handle tensor LRs.
Note on test changes:
For the test modifications I just removed itertools.product and created two loops. This allows us to create a new set of optim_inputs on each iteration to prevent mutations on the tensor LR carrying over across iterations. Nothing else in those tests was modified.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/123753
Approved by: https://github.com/janeyx99
ghstack dependencies: #123751, #123752
This resolves a bug in eager where if an old state dict is loaded (without the capturable flag) but the original dict had the capturable flag, then state_steps would be on cuda but we would take the non-capturable path. We now fallback to eager if capturable=False.
Current design doc and discussion: https://docs.google.com/document/d/1DmmbiaSp16CDZtGw1qzXKHFTY_0gqc0xpnBdviXq0vk/edit#heading=h.871u7bvwz7ze
Note on the actual fallback logic - there was an issue with torchscript originally not handling *args, **kwargs properly, after rectifying that by using `functools.wraps`, there was an additional bug with scoping which required the single tensor implementation to be in the global scope at the time of the fallback closure being created. I pass in the single tensor function to the `_disable_dynamo_if_unsupported` decorator to workaround this bug.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/123619
Approved by: https://github.com/janeyx99
Support fused_sgd_kernel support for CPU.
## Bench result:
32 core/sockets ICX
Test Scripts:
https://gist.github.com/zhuhaozhe/688763e17e93e4c5e12f25f676ec90d9https://gist.github.com/zhuhaozhe/ad9938694bc7fae8b66d376f4dffc6c9
```
Tensor Size: 262144, Num Tensor 4, Num Threads: 1
_single_tensor_sgd time: 0.2301 seconds
_fused_sgd time: 0.0925 seconds
Tensor Size: 4194304, Num Tensor 32, Num Threads: 32
_single_tensor_sgd time: 2.6195 seconds
_fused_sgd time: 1.7543 seconds
```
## Test Plan:
```
python test_optim.py -k test_fused_matches_forloop
python test_optim.py -k test_fused_large_tensor
python test_optim.py -k test_can_load_older_state_dict
python test_optim.py -k test_grad_scaling_autocast_fused_optimizers
python test_torch.py -k test_grad_scaling_autocast_fused
python test_torch.py -k test_params_invalidated_with_grads_invalidated_between_unscale_and_step
```
Looks like we already have some PRs under this issue https://github.com/pytorch/pytorch/issues/123451 to unified the UTs, I did not modified UT in this PR.
Co-authored-by: Jane Xu <janeyx@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/123629
Approved by: https://github.com/jgong5, https://github.com/janeyx99
On par with `CUDA` implementation.
For `autocast` logic, same with `CUDA` + `Fused Adam`:
- check inf in `gradscalar.step`
- In fused kernel, if there is `inf`, do nothing. If not, unscale the grad ( also write back) and update the param.
**TestPlan**:
```
# extend CUDA only test for CPU fused adagrad
python test_optim.py -k test_fused_matches_forloop
python test_optim.py -k test_fused_large_tensor
python test_torch.py -k test_grad_scaling_autocast_fused
# extend fused test
python test_torch.py -k test_params_invalidated_with_grads_invalidated_between_unscale_and_step
python test_optim.py -k test_can_load_older_state_dict
# newly added test (follow 6b1f13ea2f/test/test_cuda.py (L1108))
python test_optim.py -k test_grad_scaling_autocast_fused_optimizers
```
**Benchmark**:
**5.1x** on 56 core SPR
**Parameter-size=1M**
**Nparams=10**
[test script](https://gist.github.com/zhuhaozhe/ef9a290ad3f8f4067b3373a3bdaa33e7)
```
numactl -C 0-55 -m 0 python bench_adam.py
non-fused 6.0174267292022705 s
fused 1.1787631511688232 s
```
**Note: Fused kernel accuracy**
The accuracy failure in CI shows a little higher than default tolerance
```
2024-04-02T06:09:16.2213887Z Mismatched elements: 21 / 64 (32.8%)
2024-04-02T06:09:16.2214339Z Greatest absolute difference: 1.5735626220703125e-05 at index (6, 6) (up to 1e-05 allowed)
2024-04-02T06:09:16.2214813Z Greatest relative difference: 1.0073336852656212e-05 at index (4, 1) (up to 1.3e-06 allowed)
```
I have debug it step by step and unfortunately we may not able to make the `fused kernel` exactly same with `non fused` one due to compiler optimizations.
For example, in non-fused impl
```
exp_avg_sq.mul_(beta2).addcmul_(grad, grad.conj(), value=1 - beta2)
```
and in fused impl
```
exp_avg_sq_ptr[d] = scalar_t(beta2) * exp_avg_sq_ptr[d];
// std::cout << "exp_avg_sq " << exp_avg_sq_ptr[d] << std::endl;
exp_avg_sq_ptr[d] = exp_avg_sq_ptr[d] +
scalar_t(exp_avg_sq_grad_coefficient) * grad_val * grad_val;
```
If I keep `std::cout`, I can get exactly same results in UT
```
===============param
0.6796758770942688
0.6796758770942688
```
But when I comment out it, there will be a difference
```
===============param
0.6796758770942688
0.6796759366989136
```
So I will make the tolerance a little higher than default one.
Co-authored-by: Jane Xu <janeyx@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/123074
Approved by: https://github.com/jgong5, https://github.com/janeyx99
Fixes https://github.com/pytorch/pytorch/issues/98921
There were two issues detected:
- `MultiStepLR`: issue is described in https://github.com/pytorch/pytorch/issues/98921, this is resolved by allowlisting `collections.Counter`
- `OneCycleLR`: `state_dict['anneal_func']` is either `<function OneCycleLR._annealing_cos at 0x7f364186f5b0>` or
`<function OneCycleLR._annealing_linear at 0x7f39aa483640>` depending on the `anneal_func` kwarg.
This leads to `WeightsUnpickler error: Unsupported class __builtin__.getattr` from the `weights_only` Unpickler.
Fixed the above in a BC-compatible manner by adding `OneCyclicLR._anneal_func_type` as a string attribute and removing `OneCyclicLR.anneal_func`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/123775
Approved by: https://github.com/albanD, https://github.com/malfet
Add type hints for the function/class interfaces that appear in torch/optim/swa_utils.py but are missing in torch/optim/swa_utils.pyi.
- get_ema_multi_avg_fn
- get_swa_multi_avg_fn
- get_ema_avg_fn
- get_swa_avg_fn
- AveragedModel.__init__(multi_avg_fn)
- SWALR.get_lr
Co-authored-by: Jane (Yuan) Xu <31798555+janeyx99@users.noreply.github.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/117036
Approved by: https://github.com/janeyx99
This is the last of the old TestOptim! With this change, everything will be migrated to use OptimizerInfo. Our sparse support is...well, sparse, and the tests try to best encapsulate which configs actually work. Note that support_sparse is actually just supports sparse grads...we don't test sparse params.
1. This PR fixes a bug in Adagrad multi_tensor with maximize by passing the correct value of maximize (vs False everytime) when sparse values are present.
2. This PR does improve coverage. There used to only be 2 configs each, and now we have the following configs for:
Adagrad:
```
python test/test_optim.py -k test_rosenbrock_sparse_with_lrsched_False_Adagrad
/home/janeyx/.conda/envs/pytorch-3.10/lib/python3.10/site-packages/transformers/utils/generic.py:441: UserWarning: torch.utils._pytree._register_pytree_node is deprecated. Please use torch.utils._pytree.register_pytree_node instead.
_torch_pytree._register_pytree_node(
{'maximize': True, 'lr': 0.1}
{'initial_accumulator_value': 0.1, 'lr': 0.1} <--- this and above are CPU
.{'foreach': False, 'lr': 0.1}
{'foreach': True, 'lr': 0.1}
{'maximize': True, 'foreach': False, 'lr': 0.1}
{'maximize': True, 'foreach': True, 'lr': 0.1}
{'initial_accumulator_value': 0.1, 'foreach': False, 'lr': 0.1}
{'initial_accumulator_value': 0.1, 'foreach': True, 'lr': 0.1}
.
----------------------------------------------------------------------
Ran 2 tests in 227.744s
OK
```
SGD
```
(pytorch-3.10) [janeyx@devgpu023.odn1 /data/users/janeyx/pytorch (bff23193)]$ python test/test_optim.py -k test_rosenbrock_sparse_with_lrsched_False_SGD
/home/janeyx/.conda/envs/pytorch-3.10/lib/python3.10/site-packages/transformers/utils/generic.py:441: UserWarning: torch.utils._pytree._register_pytree_node is deprecated. Please use torch.utils._pytree.register_pytree_node instead.
_torch_pytree._register_pytree_node(
{'dampening': 0.5, 'lr': 0.0048}
.{'foreach': False, 'lr': 0.0048}
{'foreach': True, 'lr': 0.0048}
{'dampening': 0.5, 'foreach': False, 'lr': 0.0048}
{'dampening': 0.5, 'foreach': True, 'lr': 0.0048}
.
----------------------------------------------------------------------
Ran 2 tests in 112.801s
OK
```
SparseAdam
```
(pytorch-3.10) [janeyx@devgpu023.odn1 /data/users/janeyx/pytorch (bff23193)]$ python test/test_optim.py -k test_rosenbrock_sparse_with_lrsched_False_Sparse
/home/janeyx/.conda/envs/pytorch-3.10/lib/python3.10/site-packages/transformers/utils/generic.py:441: UserWarning: torch.utils._pytree._register_pytree_node is deprecated. Please use torch.utils._pytree.register_pytree_node instead.
_torch_pytree._register_pytree_node(
{'maximize': True, 'lr': 0.04}
.{'maximize': True, 'lr': 0.04}
.
----------------------------------------------------------------------
Ran 2 tests in 35.113s
OK
```
Fixes#103322. A side quest in this migration was to re-enable and track dynamo issues as they trigger on the optim tests, which will be complete from this PR. New tests may add more things to track in dynamo, but there is now an established system for doing so, and dynamo is either enabled or a bug is tracked for every migrated test in TestOptimRenewed.
Next steps:
Remove the hyperparameter constraints in common_optimizer.py defined by metadata_for_sparse (other than LR, which seems handpicked for the tests to actually pass). Doing this requires adding more sparse functionality.
Add more tests!
Maybe add more optimizers!
Pull Request resolved: https://github.com/pytorch/pytorch/pull/123146
Approved by: https://github.com/albanD
ghstack dependencies: #123134, #123139
@tfsingh I got to it first--wanted to land this stack and close the gap ASAP.
This PR also fixes a discrepancy between `_init_group` and `__set_state__` because we have the constants live on params' device always.
There are some next steps though:
- ASGD can be made faster by making etas, mus, steps be on CPU when NOT capturable. (I had mistakenly thought foreachifying was faster and so we landed https://github.com/pytorch/pytorch/pull/107857, but it is slower). No one has complained yet though. ¯\_(ツ)_/¯
Pull Request resolved: https://github.com/pytorch/pytorch/pull/121264
Approved by: https://github.com/albanD
ghstack dependencies: #121260
Finishes the work started in https://github.com/pytorch/pytorch/pull/118697. Thanks @MarouaneMaatouk for the attempt, but due to inactivity I have opened this PR for Adamax. Note that the new capturable implementation is much simpler and I've modified the foreach capturable impl--it now calls fewer kernels and is more easily comparable to forloop.
Next steps:
* This PR discovered two bugs: #121178 and #121238.
* Move the now hefty graph optim tests in test_cuda to use OptimInfo.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/121183
Approved by: https://github.com/albanD