**Background:** It's common to use `scalar_tensor()` in the input to `where()` to convert any scalars present to compatible tensors with matching options, *including layout*. This shows up in various places, notably including derivative formulas ([example](78491d6afc/tools/autograd/derivatives.yaml (L432-L434))). It causes problems for NJTs because they have `layout=torch.jagged` and it never makes sense to create a scalar tensor with this layout. Some of the breakage only seems to happen in CI for reasons I don't fully understand (see the revert of #140736 due to softshrink's derivative formula).
**This PR:**
* Allows non-contiguous NJT inputs to `where()` + adds tests for this
* Handles scalar tensor / dense tensor inputs for `condition` / `other` + adds tests for this
* Uses limited `broadcast_tensors()` / `broadcast_to()` support
* Improves `expand()` to work on non-contig NJTs
* Changes `scalar_tensor()` to use `torch.strided` instead of `torch.jagged` in both eager and torch.compile (i.e. meta registration)
* Changes backward formulas for `sinc`, `pow`, `special.i1`, and `special.i1e` to uses `scalar_tensor()` instead of e.g. `zeros({})`
**Alternative approach:** Update all problematic usages of `scalar_tensor()` to avoid ever passing `layout=torch.jagged`. This is an extensive change and includes `torch.where()` logic, a bunch of derivative formulas, and likely other places not yet discovered.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/141500
Approved by: https://github.com/malfet, https://github.com/cpuhrsch, https://github.com/soulitzer
This PR contains three `unsqueeze()`-related fixes for NJT:
1. Adjusts the output's `_ragged_idx` when `unsqueeze()` inserts a dim before the ragged dim
2. Corrects the unbind reference for `unsqueeze()` after the last input dim. For this case, the dim kwarg canonicalization logic needs to be applied wrt `inp.dim() + 1` to account for `dim=-1` properly
3. Adds ragged dim support to `unsqueeze()`, allowing for e.g. `(B, j1, D) -> (B, 1, j1, D)`. This is okay now after #137125
Note that `unsqueeze()` still doesn't support batch dim operation, and arguably should never support this.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/141392
Approved by: https://github.com/cpuhrsch
ghstack dependencies: #140736, #140161
This PR introduces `ExtraOpData`, a structure that contains op metadata regarding whether the op is a view and the dim-related args it accepts. It also populates a huge database for dim-wise / view ops with this info.
Test logic (sample input generation, references) have been updated to utilize this data. It allows for a fairly generic set of sample inputs & a reference for the class of ops that accept a single NJT and operate dim-wise (AKA "unary dimwise ops").
Testing is added over the following ops:
* `chunk()`
* `narrow()`
* `select()`
* `split()`
* `split_with_sizes()`
* `squeeze()`
* `unflatten()`
* `unsqueeze()`
Most of the above do not operate on the ragged / batch dims or on non-contiguous NJTs, so the proper xfails are added as needed.
I also slipped in a couple minor fixes (sorry):
1. The `_wrap_jagged_dim()` helper now avoids assuming the `nt._ragged_idx == 1` and allows for a batch dim to be a valid input, disambiguating the converted inner dim as necessary through an additional `operating_on_batch` return value (i.e. both dim=0 and dim=1 map to dim=0 on the inner values tensor, since that dim represents a packed ragged dim for all batch items)
2. Padded dense -> NJT conversion requires shape gymnastics to operate with the restrictive FBGEMM kernel. The gymnastics were slightly wrong for the transposed NJT case, and this PR fixes that
Pull Request resolved: https://github.com/pytorch/pytorch/pull/140161
Approved by: https://github.com/Skylion007, https://github.com/cpuhrsch
ghstack dependencies: #140736
Per discussion with @malfet, only allow weights_only unpickler to load NJT if `torch.nested` and `torch._dynamo` are imported
(this is slightly weird as technically `torch.nested` is actually imported by default and `torch._dynamo.decorators._DimRange` is actually what needs to be imported)
we can't import this from `torch.nested` as this would
- undo dynamo lazy import
- cause circular import
===========================
Redo of https://github.com/pytorch/pytorch/pull/140304 caused issues as `torch.nested._internal.foo` needs to be imported, which causes issues like
```python
torch/_weights_only_unpickler.py", line 339, in load
if full_path in _get_allowed_globals():
torch/_weights_only_unpickler.py", line 188, in _get_allowed_globals
torch.nested._internal.nested_tensor.NestedTensor
AttributeError: module 'torch.nested' has no attribute '_internal'
```
**This likely wasn't caught in our CI because imports are global during unit tests(?), so we use subprocess to properly test this time**
Differential Revision: [D65961691](https://our.internmc.facebook.com/intern/diff/D65961691)
@jbschlosser
Pull Request resolved: https://github.com/pytorch/pytorch/pull/140739
Approved by: https://github.com/malfet
This PR contains several fixes related to non-contiguous NJTs:
1. Propagates `lengths` through op calls appropriately (see desc of #138098)
* SDPA now calls `nested_view_from_values_offsets_lengths()` instead of `nested_view_from_values_offsets()`
2. Allows non-contig NJTs in unsqueeze / transpose / select
3. Expands padded dense -> NJT conversion to support non-contig NJTs
4. (unrelated sorry) Updates `split` / `split_with_sizes` to allow for optional `dim`, matching the ATen signature
Pull Request resolved: https://github.com/pytorch/pytorch/pull/140160
Approved by: https://github.com/cpuhrsch
Fixes#137512
Relaxes the restriction that the ragged dim is immediately next to the batch dim e.g. `(B, *, D_0, ..., D_N)`. This allows for constructing NJTs of shape e.g. `(B, D, j0)` directly. It's possible before this PR to get an NJT of e.g. shape `(B, D, j0)` by constructing an NJT of shape `(B, j0, D)` and transposing it. This PR allows a user to go straight there without the transpose. The standard `torch.nested.nested_tensor(list)` constructor has been updated to support this.
At the very least, this is useful for testing on transposed NJTs. I'm willing to make this functionality private if needed.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/137125
Approved by: https://github.com/cpuhrsch, https://github.com/soulitzer
I'm sick of reductions not working properly - spotty dim coverage, missing backwards, etc. This PR fixes quite a bit.
It applies to the following ops:
* `sum` / `mean` / `prod`
* `all` / `any`
* `amin` / `amax`
* `min` / `max`
* `argmin` / `argmax`
The general reduction logic has been factored out into a helper `_apply_reduction(func, func_name, identity_element, *args, **kwargs)`. The idea is that by providing a valid identity element, we can utilize conversions to padded dense when needed for reducing over the ragged dim.
Extensive test coverage includes:
* reductions across ragged dim
* reductions across non-batch, non-ragged dims
* reductions across both batch and ragged dims
* multiple dim reductions (for ops that support this)
* full reduction -> scalar
Bonus: the PR includes backwards fixes for `sum` and `mean`, which have never worked.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/139317
Approved by: https://github.com/cpuhrsch
This PR adds FlexAttention + NJT support. In particular:
* To handle raggedness, treats the packed sequence dim of input NJTs as a giant "stacked sequence". To ensure user `score_mod` / `mask_mod` functions can still be written in the original NJT sequence space, this PR handles conversions for indices within the giant "stacked sequence" -> sequence relative indices automatically.
* Provides `py_impls` for `NestedTensor` to the HOPs for flex attention forward / backward that simply wrap / unwrap NJTs appropriately
* Adds barebones `new_empty()` support to NJT since FlexAttention utilizes this repeatedly; right now, only `new_empty()` with a shape of `()` is supported
* Tests that FlexAttention with a causal mask matches causal SDPA
* Adds a new public API for FlexAttention usage:
* `create_nested_block_mask(mask_mod, B, H, njt, BLOCK_SIZE, _compile)` - NJT analogue for `create_block_mask()` that utilizes the `njt`'s ragged structure to create an appropriately-sized block mask (e.g. `(1, 1, total_seqlen, total_seqlen)`). This function handles the index conversion from "stacked sequence" space -> relative sequence space.
* Minor note: as this is a public API, this function is purposefully named with "nested" instead of "njt" to keep the latter as an informal, mostly internal-only term.
Example usage:
```python
def causal_mask(b, h, q_idx, kv_idx):
return q_idx >= kv_idx
query = ... # NJT of shape (B, H, S*, D)
key = ... # NJT of shape (B, H, S*, D)
value = ... # NJT of shape (B, H, S*, D)
# create_nested_block_mask() automatically converts indices from "stacked sequence" space -> relative sequence space
block_mask = create_nested_block_mask(causal_mask, 1, 1, query) # block mask conceptual shape is (B, H, sum(S*), sum(S*))
output = flex_attention(query, key, value, block_mask=block_mask)
def causal_score_mod(score, b, h, q_idx, kv_idx):
return torch.where(q_idx >= kv_idx, score, float("-inf"))
# flex_attention() automatically converts indices from "stacked sequence" space -> relative sequence space for NJT inputs
output2 = flex_attention(query, key, value, score_mod=causal_score_mod)
```
TODO:
* ~~Determine the right level of abstraction for public API helpers + move them alongside other helpers~~ Verify this with others though
* ~~Some cleanup~~
* ~~`njt_score_mod_adapter`~~
* ~~Q: should `create_njt_block_mask()` call `njt_mask_mod_adapter()` so we don't need two calls?~~
* Can we avoid materializing the `sum(s)` length `seq_idx` used for conversion between stacked sequence -> sequence relative indices?
* Not for now, although future work may deepen the integration between Flex + NJT (possibly requiring custom templates). We should try to cache this though.
* ~~Demonstrate non-causal mask~~
* Support non-contiguous NJTs with holes (**booted to future PR**)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/136792
Approved by: https://github.com/drisspg
ghstack dependencies: #138841
Before this PR, NJT would dispatch e.g. `NJT * nested_int` to `mul.Tensor`, wrongly interpreting the SymInt as a tensor and outputting garbage. This PR verifies that there are no nested ints in the list of args before dispatching for pointwise ops.
I originally tried checking that `the number of passed tensor args == the number of func schema tensor args`, but this wrongly disallows `nt * 2`, which (non-intuitively to me at least at first) dispatches via the `mul.Tensor` overload.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/138602
Approved by: https://github.com/soulitzer
Does what it says on the tin. I believe the right behavior here is to ensure that `record_stream()` is called on all tensor components of the NJT to ensure they all live until stream computation is complete.
This is an ask from torchrec as the op is used there.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/137099
Approved by: https://github.com/ngimel
There's an annoying pattern emerging for pulling out the NJT min / max seqlen ints if they exist without computing / caching if they don't. This PR introduces private convenience functions to simplify handling this and avoiding redundant checks.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/138130
Approved by: https://github.com/soulitzer
Our matmul support is abysmal - let's at least get this working and do it performantly later.
Bonus: implements `bmm` as well.
jagged <-> padded dense conversions are utilized when possible, and an unbind-based fallback otherwise (the former works with torch.compile and the latter doesn't). Some testing is missing because we don't have factory function support yet :(
Pull Request resolved: https://github.com/pytorch/pytorch/pull/138121
Approved by: https://github.com/cpuhrsch
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
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
Part of #134054.
This corresponds to the pytorch mypy changes from D61493706. Updating takes so
long and touches so many files that it's impossible to land as a whole without conflicting with some other intermediate change.
So landing these 'type: ignore' for pytorch in advance of them actually being needed.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/134202
Approved by: https://github.com/Skylion007
