Use object identity for deepcopy memo #126126
Closed
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
[ghstack-poisoned]
🔗 Helpful Links🧪 See artifacts and rendered test results at hud.pytorch.org/pr/126126
Note: Links to docs will display an error until the docs builds have been completed. ✅ No FailuresAs of commit 21183d5 with merge base ee8c155 ( This comment was automatically generated by Dr. CI and updates every 15 minutes. |
Copy of #126089, with some fixes & tests (TODO) [TODO description] [ghstack-poisoned]
Copy of #126089, with some fixes & tests (TODO) [TODO description] [ghstack-poisoned]
|
@davidberard98 has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator. |
Copy of #126089, with some fixes & tests (TODO) [TODO description] Differential Revision: [D57340612](https://our.internmc.facebook.com/intern/diff/D57340612) [ghstack-poisoned]
|
@davidberard98 has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator. |
|
@pytorchbot merge -f 'Landed internally' (Initiating merge automatically since Phabricator Diff has merged, using force because this PR might not pass merge_rules.json but landed internally) |
Merge startedYour change will be merged immediately since you used the force (-f) flag, bypassing any CI checks (ETA: 1-5 minutes). Please use Learn more about merging in the wiki. Questions? Feedback? Please reach out to the PyTorch DevX Team |
Merge failedReason: Command Details for Dev Infra teamRaised by workflow job |
Copy of #126089, with some additional fixes & tests Partial fix for #125635: previously, the deepcopy implementation would group together any tensors with any aliasing relationship and assign them to the same tensor. This was sort of good if you have two tensors `b = a.detach()`, because then if you deepcopy `list = [a, b]` to `list2 = list.deepcopy()`, then writes to `list2[0]` will also modify `list2[1]`. But for the most part, it's bad; (1) if you have `b = a.as_strided((4, 4), (16, 1), 16)`, then it'll make `b == a` in the deepcopied implementation, which is completely wrong; and (2) even if you have `b = a.detach()`, these are still initially two different tensors which become the same tensor after the old deepcopy implementation. The new implementation only groups together tensors that have the same identity. This is a partial fix, but it's more reasonable. What changes: * (becomes more correct): different views of the same base tensor will no longer all become equal after deepcopying * (still kind of wrong): views won't actually alias each other after deepcopying. * (arguably a minor regression): equivalent views of the same tensor will no longer be copied to the same tensor - so they won't alias. BC breaking: C++ deepcopy interface changes from accepting `IValue::HashAliasedIValueMap memo` to accepting `IValue::HashIdentityIValueMap memo`. If there are objections, we can keep the old API. However, it seems likely that users generally won't try to deepcopy from C++. Differential Revision: [D57340612](https://our.internmc.facebook.com/intern/diff/D57340612) cc ezyang gchanan [ghstack-poisoned]
|
@davidberard98 has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator. |
|
@pytorchbot merge this landed internally already, but the bot didn't merge it in OSS |
Merge startedYour change will be merged once all checks pass (ETA 0-4 Hours). Learn more about merging in the wiki. Questions? Feedback? Please reach out to the PyTorch DevX Team |
ZelboK
pushed a commit
to ZelboK/pytorch
that referenced
this pull request
May 19, 2024
Copy of pytorch#126089, with some additional fixes & tests Partial fix for pytorch#125635: previously, the deepcopy implementation would group together any tensors with any aliasing relationship and assign them to the same tensor. This was sort of good if you have two tensors `b = a.detach()`, because then if you deepcopy `list = [a, b]` to `list2 = list.deepcopy()`, then writes to `list2[0]` will also modify `list2[1]`. But for the most part, it's bad; (1) if you have `b = a.as_strided((4, 4), (16, 1), 16)`, then it'll make `b == a` in the deepcopied implementation, which is completely wrong; and (2) even if you have `b = a.detach()`, these are still initially two different tensors which become the same tensor after the old deepcopy implementation. The new implementation only groups together tensors that have the same identity. This is a partial fix, but it's more reasonable. What changes: * (becomes more correct): different views of the same base tensor will no longer all become equal after deepcopying * (still kind of wrong): views won't actually alias each other after deepcopying. * (arguably a minor regression): equivalent views of the same tensor will no longer be copied to the same tensor - so they won't alias. BC breaking: C++ deepcopy interface changes from accepting `IValue::HashAliasedIValueMap memo` to accepting `IValue::HashIdentityIValueMap memo`. If there are objections, we can keep the old API. However, it seems likely that users generally won't try to deepcopy from C++. Differential Revision: [D57406306](https://our.internmc.facebook.com/intern/diff/D57406306) Pull Request resolved: pytorch#126126 Approved by: https://github.com/ezyang
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4B46
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Stack from ghstack (oldest at bottom):
Copy of #126089, with some additional fixes & tests
Partial fix for #125635: previously, the deepcopy implementation would group together any tensors with any aliasing relationship and assign them to the same tensor. This was sort of good if you have two tensors
b = a.detach(), because then if you deepcopylist = [a, b]tolist2 = list.deepcopy(), then writes tolist2[0]will also modifylist2[1]. But for the most part, it's bad; (1) if you haveb = a.as_strided((4, 4), (16, 1), 16), then it'll makeb == ain the deepcopied implementation, which is completely wrong; and (2) even if you haveb = a.detach(), these are still initially two different tensors which become the same tensor after the old deepcopy implementation.The new implementation only groups together tensors that have the same identity. This is a partial fix, but it's more reasonable. What changes:
BC breaking: C++ deepcopy interface changes from accepting
IValue::HashAliasedIValueMap memoto acceptingIValue::HashIdentityIValueMap memo. If there are objections, we can keep the old API. However, it seems likely that users generally won't try to deepcopy from C++.cc @ezyang @gchanan
Differential Revision: D57406306