For `autograd.Function`, the engine will try to allocate correctly-shaped zeros for `None` grads (i.e. in the case where the output isn't used downstream). It determines the shape of these zeros from the `VariableInfo` entry, which is derived from the forward output shape. For the NJT forward output case, the size info stored will contain a nested int, and calling `zeros()` with this size throws:
```
RuntimeError: .../build/aten/src/ATen/RegisterCPU.cpp:5260: SymIntArrayRef expected to contain only concrete integers
```
This PR fixes this by storing the full tensor in the `VariableInfo` for the nested case and calling `zeros_like()` to allocate correctly-shaped zeros. This is pretty inefficient; ideally we would want to save just the NJT shape and be able to construct zeros from it, but this requires factory function support for nested ints (WIP). So this is a short-term fix until we have that.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/136875
Approved by: https://github.com/soulitzer, https://github.com/huydhn
For `autograd.Function`, the engine will try to allocate correctly-shaped zeros for `None` grads (i.e. in the case where the output isn't used downstream). It determines the shape of these zeros from the `VariableInfo` entry, which is derived from the forward output shape. For the NJT forward output case, the size info stored will contain a nested int, and calling `zeros()` with this size throws:
```
RuntimeError: .../build/aten/src/ATen/RegisterCPU.cpp:5260: SymIntArrayRef expected to contain only concrete integers
```
This PR fixes this by storing the full tensor in the `VariableInfo` for the nested case and calling `zeros_like()` to allocate correctly-shaped zeros. This is pretty inefficient; ideally we would want to save just the NJT shape and be able to construct zeros from it, but this requires factory function support for nested ints (WIP). So this is a short-term fix until we have that.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/136875
Approved by: https://github.com/soulitzer
Fixes#129366
Since NJT has custom serialization logic, we need an NJT-specific fix to clear out cached sizes / strides PyCapsules. Eventually, we should switch NJT to use the default serialization logic, but this depends on #125622 being addressed.
This PR also makes serialization more complete by explicitly handling `lengths`, `ragged_idx`, and the `metadata_cache`, ensuring working operation for both contiguous and non-contiguous NJTs,
Pull Request resolved: https://github.com/pytorch/pytorch/pull/137031
Approved by: https://github.com/soulitzer
ghstack dependencies: #137030
Prior to this PR, calling `reshape()` under `inference_mode()` would throw a `NotImplementedError`. This is because `inference_mode()` disables autograd key dispatch, incidentally preventing the decomposition of reshape for NJT.
This PR fixes this by redispatching on the `CompositeImplicitAutogradNestedTensor` key whenever a composite implicit op is encountered in `NJT.__torch_dispatch__()`. This fixes reshape and any other composite implicit ops underneath `inference_mode()`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/134683
Approved by: https://github.com/soulitzer, https://github.com/albanD
ghstack dependencies: #136566
Related: #132695
This PR uses padded dense <-> jagged conversions to handle binary pointwise broadcasting of (NT, T) and (T, NT). This includes:
* `(B, j0, D) + (1, 1, 1)`
* `(B, j0, D) + (B, 1, 1)`
* `(B, j0, D) + (B, 1, D)`
* etc.
This PR also adds (hacky) support for bool inputs to the jagged <-> padded dense conversions. The underlying CUDA kernels do not support integer / bool inputs; so the following workaround is employed: `convert input -> half, run conversion kernel, convert output -> bool`. Note that this bool support is needed specifically for the backward formula of `fmax`, and likely others.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/133021
Approved by: https://github.com/cpuhrsch
`rms_norm()` is a nice-to-have for ViT :)
This PR:
* SymInt-ifies `rms_norm()`, allowing NJT to use the same decomp.
* Adds torch_function-based input validation logic for nested-specific stuff (no normalization supported over the ragged dim for now) on the python NJT side.
* Adds multi-dim support (on non-ragged, non-batch dims) to `mean()` for NJT.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/135872
Approved by: https://github.com/mikaylagawarecki
ghstack dependencies: #125947
This PR solves two problems with `sum()` support in NJT:
* `sum()` over a dim with `keepdim=True` returns the wrong shape (i.e. it'll keep the wrong dim). This is a long-standing bug from way back in #112519.
* Historically, we've only supported `sum()` over a dim and not a full reduction. This PR adds the full reduction form (forward only, backward still fails).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131945
Approved by: https://github.com/davidberard98, https://github.com/jananisriram
This PR:
* Implements the pre-existing `nt.to_padded_tensor(padding_val)` ATen op via the FBGEMM kernel + appropriate view gymnastics (since that kernel only handles 2D values)
* Introduces a new `_nested_from_padded_tensor` op for the reverse conversion, implemented via the reverse FBGEMM kernel + view gymnastics
* Note: there is currently no public API for this; design booted to a future PR
TODO:
* ~~Propagate min / max sequence length via the new factory function `_nested_from_padded_tensor`~~
* ~~Verify that Inductor does computation fusion via test logic~~
Pull Request resolved: https://github.com/pytorch/pytorch/pull/125947
Approved by: https://github.com/soulitzer
This PR:
* Implements the pre-existing `nt.to_padded_tensor(padding_val)` ATen op via the FBGEMM kernel + appropriate view gymnastics (since that kernel only handles 2D values)
* Introduces a new `_nested_from_padded_tensor` op for the reverse conversion, implemented via the reverse FBGEMM kernel + view gymnastics
* Note: there is currently no public API for this; design booted to a future PR
TODO:
* ~~Propagate min / max sequence length via the new factory function `_nested_from_padded_tensor`~~
* ~~Verify that Inductor does computation fusion via test logic~~
Pull Request resolved: https://github.com/pytorch/pytorch/pull/125947
Approved by: https://github.com/soulitzer
Summary:
When exporting for training with `tolist`, we do not hit `FunctionalTensor.tolist` since we do not functionalize. Unfortunately, this means we hit `FakeTensor.tolist`, which creates unbacked symints that are not backed by proxies.
Rather than trying to patch up this low-level implementation, we replace it with essentially what `FunctionalTensor.tolist` does, which is higher-level: we essentially desugar to `item()` calls and let it take care of unbacked symints.
Test Plan:
Some expected failures are gone now.
Also found a test for `tolist` that was written when `FunctionalTensor.tolist` was implemented but not really doing much; repurposed it now to exercise more modes.
Differential Revision: D62197742
Pull Request resolved: https://github.com/pytorch/pytorch/pull/135131
Approved by: https://github.com/ezyang
A user wants to use the flop counter with meta devices. This previously caused problems for SDPA+NJT:
1. autocast check: `torch.is_autocast_enabled("meta")` fails because `meta` is not valid for autocasting. If we skip this, we run into the next error
2. math backend: conversion to NST requires getting concrete offsets in a list of python integers, which doesn't work on a meta tensor b2eb0e8c6a/torch/nested/_internal/sdpa.py (L809-L815)
3. (fixed in the previous PR, #134288) - if we force using flash attention backend for flop counting, `_flash_attention_forward` previously didn't support meta tensors.
In this PR, we check specifically for FlopCounterMode, and, if it's enabled and combined with meta tensors, (a) skip autocasting and (b) force it down the flash attention path. This isn't generally safe for tracing (e.g. if you actually care which kernels you are running), but in the absence of actual device information, we have to make some assumptions. By specifically checking for FlopCounterMode, this should reduce the chance of unintended side effects for other meta tensor users.
Note: fake tensor would solve a bunch of these issues, but it's not a viable solution right now for the user.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/134289
Approved by: https://github.com/soulitzer
ghstack dependencies: #134288
It's possible to construct an NJT with "holes" by specifying both `offsets` and `lengths` metadata. When `nt.clone(memory_format=torch.contiguous_format)` is called on such an NJT, the result should be an NJT without holes.
This PR fixes this in simplistic way using `unbind()`, which isn't really supported in `torch.compile`. The longer term solution involves writing a proper kernel to support this.
NB: Another limitation is that the returned NJT does not have the same ragged structure as the input. While we could manually hack the nested int registry (or update the union find when that lands), this is the first instance where a NJT with holes and an NJT without holes could have the same ragged structure, and getting those to play nicely together requires some fairly involved updates. For now, this PR punts on these updates until we can clean this up.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/132776
Approved by: https://github.com/ani300, https://github.com/soulitzer
ghstack dependencies: #131898, #131704, #131937
Summary:
Modify `softmax` on the ragged dimension, where `ragged_idx == 1`, to allow for 2D nested tensors. This diff now enables a `softmax` operation on tensors of shape `(B, *)`, where `*` is the ragged dimension.
Extend existing `softmax` unit tests to include 2D nested tensors using the `include_2d_tensor=True` keyword argument.
Test Plan:
Verify that existing and modified unit tests pass using the following commands:
```
buck2 run mode/{opt,inplace} //caffe2/test:nested -- --regex test_softmax
```
```
buck2 run mode/{opt,inplace} //caffe2/test:nested -- --regex test_jagged_op
```
Reviewed By: davidberard98
Differential Revision: D60780975
Pull Request resolved: https://github.com/pytorch/pytorch/pull/132812
Approved by: https://github.com/davidberard98
When autocasting is turned on, right now SDPA w/ NJT won't be autocasted. This PR adds manual "autocasting" logic in sdpa.py - at the beginning, it just checks if autocasting is enabled, and if so, it casts the inputs in the way you would expect if autocasting was actually running.
Why normal autocasting won't work:
* NJT intercepts the `__torch_function__` call for scaled_dot_product_attention, which, AFAIK, happens before we get to any dispatcher logic, and then calls efficient attention or flash attention. So autocasting the scaled_dot_product_attention op won't work; we never call the aten op for scaled_dot_product_attention, so we won't ever run autocasting for it.
* If we try to add autocasting handling for `_flash_attention_forward` or `_efficient_attention_forward`, then autocasting will _run_, but it will have the wrong semantics: sdpa.py's handling will run first, and it will do backend selection based on the uncasted inputs to SDPA. This also means that if the inputs to the SDPA call don't have uniform types, the sdpa.py implementation will fail checks (this is the specific issue we're targeting).
Alternative: "just change the backend selection logic for NJT to be autocast aware, but don't actually do the autocast; then, add `_(flash|efficient)_attention_forward` to autocasting rules". I think this would work too. But it's arguably better to make the backend-selection logic and actual-autocast-behavior use the same implementation, in case the implementations are different.
Differential Revision: [D60879916](https://our.internmc.facebook.com/intern/diff/D60879916)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/132835
Approved by: https://github.com/soulitzer
This PR does 3 things:
1. Adds a copy-free strided->jagged layout conversion for NT
2. Adds a copy-free jagged->strided layout conversion for NT
3. Modifies and expands the .to() API to support the layout argument for the specific case of NT layout conversion.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/115749
Approved by: https://github.com/jbschlosser
Combines contributions from https://github.com/pytorch/pytorch/pull/130505
Some context can be found in this large comment block:
a5b64d39fd/test/dynamo/test_subclasses.py (L1667-L1681)
Changes in this PR
- For each tensor fakified, check the nested int registry in eager, and eagerly symbolicize if that tensor has already been associated with nested int in eager.
- Adds a separate counter stored on FakeTensorMode as a fake analog to _tensor_id_counter (which keeps track of unique tensors). This counter is initialized to the global eager tensor id counter upon creation of the FakeTensorMode, and needs to be reset when the same FakeTensorMode is reused to trace again (in this PR, we piggyback on the epoch incrementing logic).
- (refactor) Today, we store FakeTensor -> symbolic nested int in the global registry. With this PR, symbolic nested int is stored directly on the FakeTensor. (Eager still caches nested int in the registry, though we should avoid this at some point.)
Basically unchanged, but worth noting:
- `__tensor_unflatten__` is still responsible for determining whether we should cache for now. The logic is somewhat simplified.
- to_copy is still using the trick of updating two different tensors in the registry to point to the same nested int. This is kind of broken, but we try to leave it as is, and plan a better fix with the UnionFind stack.
Differential Revision: [D60406772](https://our.internmc.facebook.com/intern/diff/D60406772)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/130292
Approved by: https://github.com/bdhirsh
ghstack dependencies: #131916, #131803
This PR does 3 things:
1. Adds a copy-free strided->jagged layout conversion for NT
2. Adds a copy-free jagged->strided layout conversion for NT
3. Modifies and expands the .to() API to support the layout argument for the specific case of NT layout conversion.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/115749
Approved by: https://github.com/jbschlosser
mvlgamma backward trips DEBUG=1 asserts when trying to construct an empty tensor with `layout=torch.jagged`. This happens due to passing `self.options()` to `arange()` in `mvlgamma_backward()`. Fix in this PR unconditionally constructs `arange()` with the strided layout.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/132422
Approved by: https://github.com/albanD
**Background:** NJT utilizes a `jagged_unary_pointwise()` fallback that historically has assumed blindly that the first arg is an NJT. This assumption breaks certain ops; for example `pow(scalar, Tensor)` has an NJT as the second arg.
This PR expands `jagged_unary_pointwise()` and the associated schema validation logic to handle an NJT in args other than the first position.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131937
Approved by: https://github.com/soulitzer
ghstack dependencies: #131898, #131704
Modify the existing `layer normalization` operator in PyTorch, invoked by `torch.layer_norm`, to allow for reductions along the jagged dimension of a nested tensor. The function originally had a basic implementation for reducing along 1 non-ragged dimension. This diff, which uses the `aten` padding operator, enables PyTorch users to invoke `torch.nn.functional.layer_norm` on a nested tensor when reducing along the ragged dimension, e.g. `*` in a `(B, *, M)` or `(B, *, M, N)` nested tensor.
Write unit tests based on the `softmax` jagged operator to verify the accuracy of the ragged reduction implementation for `torch.nn.functional.layer_norm`. Add unit tests to verify error handling for unsupported features.
Note that this implementation is limited to nested tensors with `ragged_idx == 1`, i.e. the ragged dimension is not transposed. The layer normalization operator also requires an operation on a 2-dimensional layer; for nested tensors with 4 or more dimensions, I flatten the extra dimensions, then unflatten them after performing layer normalization.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/132172
Approved by: https://github.com/davidberard98
ghstack dependencies: #132170
Modify the existing `softmax` operator in PyTorch, invoked by `torch.softmax`, to allow for reductions along the jagged dimension of a nested tensor. The function originally had a basic implementation for reducing along 1 non-ragged dimension. This diff, which uses the aten padding operator, enables PyTorch users to invoke `torch.softmax` on a nested tensor when reducing along the ragged dimension, e.g. `*` in a `(B, *, M)` nested tensor.
Write unit tests based on the `sum` and `mean` jagged operators to verify the accuracy of the ragged reduction implementation for `torch.softmax`. Add unit tests to verify error handling for unsupported features in `NestedTensor` `torch.softmax`.
Note that this implementation is limited to nested tensors with `ragged_idx == 1`, i.e. the ragged dimension is not transposed. In addition, the `softmax` operator is required to take in as input an integer for the reduction dimension `dim`, requiring new unit tests heavily inspired by the `sum` and `mean` jagged operator unit tests. `Softmax` also allows for reducing along the batch dimension.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/132170
Approved by: https://github.com/davidberard98
This PR utilizes the info from the existing OpInfo database `op_db` to contribute to general NJT testing.
* New tests in `TestNestedTensorOpInfo`
* `test_forward()` - compares forward output to an unbind-based reference
* `test_backward()` - compares forward output and grads to an unbind-based reference
* `test_forward_compile()` - compares forward compile output (`backend="aot_eager_decomp_partition"`) to eager
* `test_backward_compile()` - compares forward compile output (`backend="aot_eager_decomp_partition"`) and grads to eager
* To avoid adding a bunch of NJT-specific stuff to the `OpInfo` structure, this PR translates `op_db` -> a NJT-specific `njt_op_db`.
* `UnaryUfuncInfo`s utilize a new `sample_inputs_unary_njt_pointwise()` which iterates through a comprehensive list of NJTs: contiguous / non-contiguous, dims 2, 3, and 4, transposed / not, etc.
* `BinaryUfuncInfo`s utilize a new `sample_inputs_binary_njt_pointwise()` which iterates through a comprehensive list of NJTs: contiguous / non-contiguous, dims 2, 3, and 4, transposed / not, etc.
* `ReductionOpInfo`s utilize a new `sample_inputs_njt_reduction()` which covers full reductions, reductions over the jagged dim, and reductions over the non-jagged dim
* Several xfails were added to get things passing
TODO (future PRs):
* Pass non-contiguous / non-contiguous with holes NJTs (maybe we should have separate tests for these? most ops don't support NJTs with holes today)
* Mixed (NT, T), (T, NT) inputs for binary ops
* Handle other types of OpInfos (beyond unary pointwise, binary pointwise, and reduction) by manually by writing sample_inputs_funcs
* Address all xfails via fixes
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131704
Approved by: https://github.com/soulitzer
ghstack dependencies: #131898
**Background**: `TestCase.assertEqual()` is commonly used during test case validation. Historically, to support NSTs, the logic was written to compare two nested tensors by unbinding them and comparing their components. This logic applied to NJTs as well, which in practice meant that two NJTs with different nested ints in their shapes could compare equal if their components were equal.
This PR changes the above logic so that NJTs are no longer unbound during comparison, allowing them to receive full shape validation. This makes `TestCase.assertEqual()` stricter for NJTs, requiring them to have the same nested ints in their shapes to compare equal.
Note that some tests rely on the old, looser behavior. To address this, the PR introduces a base `NestedTensorTestCase` that defines a helper function `assertEqualIgnoringNestedInts()` so that these tests can explicitly opt in to the looser comparison behavior.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131898
Approved by: https://github.com/soulitzer
Modify the existing `layer normalization` operator in PyTorch, invoked by `torch.layer_norm`, to allow for reductions along the jagged dimension of a nested tensor. The function originally had a basic implementation for reducing along 1 non-ragged dimension. This diff, which uses the `aten` padding operator, enables PyTorch users to invoke `torch.nn.functional.layer_norm` on a nested tensor when reducing along the ragged dimension, e.g. `*` in a `(B, *, M)` or `(B, *, M, N)` nested tensor.
Write unit tests based on the `softmax` jagged operator to verify the accuracy of the ragged reduction implementation for `torch.nn.functional.layer_norm`. Add unit tests to verify error handling for unsupported features.
Note that this implementation is limited to nested tensors with `ragged_idx == 1`, i.e. the ragged dimension is not transposed. The layer normalization operator also requires an operation on a 2-dimensional layer; for nested tensors with 4 or more dimensions, I flatten the extra dimensions, then unflatten them after performing layer normalization.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131519
Approved by: https://github.com/davidberard98
ghstack dependencies: #131518
Modify the existing `layer normalization` operator in PyTorch, invoked by `torch.layer_norm`, to allow for reductions along the jagged dimension of a nested tensor. The function originally had a basic implementation for reducing along 1 non-ragged dimension. This diff, which uses the `aten` padding operator, enables PyTorch users to invoke `torch.nn.functional.layer_norm` on a nested tensor when reducing along the ragged dimension, e.g. `*` in a `(B, *, M)` or `(B, *, M, N)` nested tensor.
Write unit tests based on the `softmax` jagged operator to verify the accuracy of the ragged reduction implementation for `torch.nn.functional.layer_norm`. Add unit tests to verify error handling for unsupported features.
Note that this implementation is limited to nested tensors with `ragged_idx == 1`, i.e. the ragged dimension is not transposed. The layer normalization operator also requires an operation on a 2-dimensional layer; for nested tensors with 4 or more dimensions, I flatten the extra dimensions, then unflatten them after performing layer normalization.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131519
Approved by: https://github.com/davidberard98
ghstack dependencies: #131518
Modify the existing `softmax` operator in PyTorch, invoked by `torch.softmax`, to allow for reductions along the jagged dimension of a nested tensor. The function originally had a basic implementation for reducing along 1 non-ragged dimension. This diff, which uses the aten padding operator, enables PyTorch users to invoke `torch.softmax` on a nested tensor when reducing along the ragged dimension, e.g. `*` in a `(B, *, M)` nested tensor.
Write unit tests based on the `sum` and `mean` jagged operators to verify the accuracy of the ragged reduction implementation for `torch.softmax`. Add unit tests to verify error handling for unsupported features in `NestedTensor` `torch.softmax`.
Note that this implementation is limited to nested tensors with `ragged_idx == 1`, i.e. the ragged dimension is not transposed. In addition, the `softmax` operator is required to take in as input an integer for the reduction dimension `dim`, requiring new unit tests heavily inspired by the `sum` and `mean` jagged operator unit tests. `Softmax` also allows for reducing along the batch dimension.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131518
Approved by: https://github.com/davidberard98
