Summary: We need real_tensor on the FakeTensor in node.meta["val"] in order to aot_compile the draft exported programs. Otherwise, we cannot propagate real tensors even when fake_mode.propagate_real_tensors = True.
This also fixes real tensor propagation in `run_decomposition()`.
Test Plan:
```
buck2 run @mode/dev-nosan caffe2/test:test_export -- -r test_dedup_data_dependent_failure
```
Differential Revision: D72732714
Pull Request resolved: https://github.com/pytorch/pytorch/pull/150948
Approved by: https://github.com/angelayi
Summary:
When we divide a FakeTensor by an integer using the fast op implementation, the type promotion should be `ELEMENTWISE_TYPE_PROMOTION_KIND.INT_TO_FLOAT` so we get a float when dividing an int FakeTensor by an integer.
```
FAST = get_fast_op_impls()
fast_div = FAST[torch.ops.aten.div.Tensor]
fast_div(fake_tensor, some_int)
```
Test Plan:
```
python test/test_fake_tensor.py -k test_fast_div
```
Differential Revision: D72667430
Pull Request resolved: https://github.com/pytorch/pytorch/pull/150874
Approved by: https://github.com/angelayi
* Automatically applies ruff rule 401. Turns loops into equivalent list comprehensions which are faster and do not leak the scope of the loop variables.
* list comprehensions not only often have better typing, but are 50+% faster than for loops on overhead. They also preserve length information etc and are better for the interpreter to optimize.
* Manually went back and made mypy happy after the change.
* Also fixed style lints in files covered by flake8 but not by pyfmt
Pull Request resolved: https://github.com/pytorch/pytorch/pull/140980
Approved by: https://github.com/justinchuby, https://github.com/malfet
During export, we nub out most CIA ops to return NotImplemented to avoid decomposing them during tracing. To recover the existing shape propagation behavior, we register these CIA decomps directly as FakeTensorMode rules as well. The reason we have to do is because when we return NotImplemented, FakeTensor would fallback to running these CIAs with Meta backend causing device branching CIA ops to fail. (because now the device is Meta. One example is sdpa). If we register a kernel directly to FakeTensorMode, we won't fallback to Meta backend.
Differential Revision: [D65716260](https://our.internmc.facebook.com/intern/diff/D65716260/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/140465
Approved by: https://github.com/bdhirsh
### Summary
The fake impl for `nonzero` sets the symint's upper range to `sys.maxsize - 1` if there are any SymInts in the original input tensor shape. This PR constrains the range more intelligently by using the upper ranges of each SymInt in the input tensor shape.
See https://github.com/pytorch/pytorch/pull/134899 as a merged solution for a similar problem for a different op.
### Test plan
Added unit test to verify upper bound reduction calculation (`python test/export/test_export.py TestExport.test_nonzero_dynamic`)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/137663
Approved by: https://github.com/ezyang
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
At the moment, the fake impl for `masked_select` simply sets the upper range while updating its size-like SymInt to `sys.maxsize`(9223372036854775807, max value for an unsigned int64) if the there are any SymInts in the original input tensor shape. This PR constrains the range more intelligently by using the upper ranges of each SymInt in the input tensor shape.
This solves an issue where an model being lowered to Executorch errors during memory planning because the memory allocated for `masked_select` ended up exceeded the 64-bit address space (`INT_MAX * size(dtype)`).
## Test plan
- Passes existing unit tests (tests case where upper bound is inf)
- Added unit test to verify upper bound reduction calculation
- Tested end-to-end by exporting with TORCH_LOGS="export" and ensuring that the range for `masked_select`'s SymInt size has the correct upper bound
Pull Request resolved: https://github.com/pytorch/pytorch/pull/134899
Approved by: https://github.com/ezyang
See #121528 for additional context.
In #120682, we moved the attention kernels from meta_registrations to fake_impls with the intent of fixing the device handling for seed/offset: these are typically on CPU. We needed to put the registrations in fake_impls to do this because meta_registrations doesn't have a way to specify device, whereas fake_impls does. But when we tried to actually fix the device types (#120839), we had to revert the PR because it broke cudagraph handling (during which seed/offset _are_ on CUDA).
Now, we want to put the registrations back in meta_registrations so that we can call these kernels with meta tensors. The use case is later in this stack - we want to be able to use the flop counter with these kernels.
Also - I specifically skip the `compare_tensor_meta()` check in test_fake / test_fake_autocast tests for the `_efficient_attention_forward` and `_flash_attention_forward` kernels, which fails because of the device mismatch from the seed/offset tensors. Then we can un-skip these opinfos. I verified that the efficient_attention_forward bug (#120842) is now caught by these opinfos if I revert the fix from this PR.
Differential Revision: [D61687369](https://our.internmc.facebook.com/intern/diff/D61687369)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/134288
Approved by: https://github.com/drisspg
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
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
Looks like one of the first failures seen is `test_causal_variants_compile_causal_variant_CausalVariant_LOWER_RIGHT_shape0_cuda` when `test_causal_variants_causal_variant_CausalVariant_LOWER_RIGHT_shape0_cuda` passes.
What seems interesting here is that the `torch.compile` version fails while the eager version passes. Not sure what the difference would be here...
Nevertheless, is there a recommended mechanism to skip cuDNN SDPA as a backend for this test? CC @drisspg
Pull Request resolved: https://github.com/pytorch/pytorch/pull/125343
Approved by: https://github.com/Skylion007
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
Looks like one of the first failures seen is `test_causal_variants_compile_causal_variant_CausalVariant_LOWER_RIGHT_shape0_cuda` when `test_causal_variants_causal_variant_CausalVariant_LOWER_RIGHT_shape0_cuda` passes.
What seems interesting here is that the `torch.compile` version fails while the eager version passes. Not sure what the difference would be here...
Nevertheless, is there a recommended mechanism to skip cuDNN SDPA as a backend for this test? CC @drisspg
Pull Request resolved: https://github.com/pytorch/pytorch/pull/125343
Approved by: https://github.com/Skylion007
Backporting a few fixes from xFormers:
* Bug fixes for local attention (which is not exposed in PT at the moment)
* Massively reduced memory usage on the BW pass (see also https://github.com/facebookresearch/xformers/pull/1028)
Essentially this will also make xFormers build process much easier, as we will be able to use mem-eff from PyTorch (if the user has a recent enough version) rather than building it at xFormers install time
The goal is to have the source of truth for these files in PT moving forward, and remove them from xFormers eventually once our users have a recent-enough version of PT.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/127090
Approved by: https://github.com/drisspg
Follow-up to #113118 and #124306.
Developed in coordination with the solution to https://github.com/microsoft/onnxscript/pull/1547
This PR adds the missing fake tensor implementation for `aten.unique_dim`, thus enabling tracing and compilation of `torch.unique` when `dim` is not None.
Local testing has proceeded with the following simple script (provided that one has checked out the changes in https://github.com/microsoft/onnxscript/pull/1547):
```python
import onnx
import onnxruntime as ort
import logging
import numpy as np
onnx_program = torch.onnx.dynamo_export(
lambda x: torch.unique(x,
dim=0,
return_inverse=True),
torch.arange(10),
export_options=torch.onnx.ExportOptions(
dynamic_shapes=True,
diagnostic_options=torch.onnx.DiagnosticOptions(
verbosity_level=logging.DEBUG)))
onnx_program.save("torch_unique.onnx")
onnx_inputs = onnx_program.adapt_torch_inputs_to_onnx(torch.arange(10))
onnx_outputs = onnx_program(*onnx_inputs)
loaded_onnx_program = onnx.load("torch_unique.onnx")
onnx.checker.check_model(loaded_onnx_program)
ort_session = ort.InferenceSession("torch_unique.onnx")
inputs = np.random.randint(0, 10, 10)
print(f"Inputs: {inputs}")
outputs = ort_session.run(None,
{
"l_x_": inputs
})
print(f"Outputs: {outputs}")
print("Success")
```
Co-authored-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/126561
Approved by: https://github.com/ezyang
1. **Expose seqused_k & alibi_slopes arguments**:
- This can be used when your sequence length k is not the full extent of the tensor. This is useful for kv cache scenarios and was not previously supported in the FA2 TORCH integration. We need these arguments for external xformers lib call to the _flash_attention_forward API.
Before:
```
std::optional<Tensor> seqused_k = c10::nullopt;
std::optional<Tensor> alibi_slopes = c10::nullopt;
```
After:
```
_flash_attention_forward(...
std::optional<Tensor>& seqused_k,
std::optional<Tensor>& alibi_slopes,
```
2. There is a difference between the **TORCH_FA2_flash_api:mha_fwd** and **FA2_flash_api:mha_fwd** (same for **mha_varlen_fwd**) at the query transposition (GQA) step.
The **CHECK_SHAPE** is applied on the original query vs the reshaped query. This causes an error (because of the shape constraint) for such inputs:
```
q = torch.randn([7, 1, 4, 256], dtype=torch.bfloat16, device='cuda')
k = torch.randn([7, 51, 1, 256], dtype=torch.bfloat16, device='cuda')
v = torch.randn([7, 51, 1, 256], dtype=torch.bfloat16, device='cuda')
```
- i've modified the code as little as possible, but if you prefer a more verbose change like the following, dont hesitate to tell me:
```
at::Tensor swapped_q = seqlenq_ngroups_swapped
? q.reshape({batch_size, num_heads_k, num_heads / num_heads_k, head_size_og}).transpose(1, 2)
: q;
if (seqlenq_ngroups_swapped) {
seqlen_q = num_heads / num_heads_k;
num_heads = num_heads_k;
}
CHECK_SHAPE(swapped_q, batch_size, seqlen_q, num_heads, head_size_og);
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/126520
Approved by: https://github.com/drisspg
This PR requires a little justification, but let's start with what it does first:
1. When you have a 0d CPU scalar int64/float64 tensor input to a graph, we will preallocate a backed SymInt/SymFloat corresponding to what you would get if you call item() on this tensor. This means you can freely change your input to be a Python int/float or a Tensor with an item() call and end up with exactly the same level of expressivity (specifically, you can guard on the internal SymInt/SymFloat no matter what). By default, the source of the backed SymInt/SymFloat is `L['tensor'].item()`, but if you have promoted a float input into a Tensor, we will cancel out `torch.as_tensor(L['float']).item()` into just `L['float']`.
2. We switch wrap_symfloat to use this, instead of hand crafting the new SymNodeVariable. Everything works out, except that we carefully pass the item() result to tracked fakes (and not the fake Tensor argument)
OK, so why do this at all? There is some marginal benefit where now some item() calls on scalar inputs can be guarded on, but IMO this is a pretty marginal benefit, and if it was the only reason, I wouldn't do this. The real reason for this is that I need to be able to propagate fake tensors through the graphs that are produced by Dynamo, and if I am doing the old custom wrap_symfloat logic, there's no way I can do this, because ordinarily an item() call will cause an unbacked SymInt when I reallocate.
The other obvious way to solve the problem above is to make a HOP alternative that item() that "bakes in" the backed SymInt its supposed to return. But this strategy seems more parsimonious, and it does have the marginal benefit I mentioned above. The main downside is that what I have to do next, is make it so that when I run tensor computation, I also apply the equivalent operations to the SymInt/SymFloat as well. That's next PR.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/126245
Approved by: https://github.com/eellison
ghstack dependencies: #126637
A common complaint when working with data-dependent code in PyTorch is that it's hard to tell how far you are from the finish line: every time a GuardOnDataDependentSymNode error is hit, you have to somehow fix or workaround it to see the next one.
This PR adds a new mode `torch._functorch.config.fake_tensor_propagate_real_tensors` which modifies fake tensors to also propagate real tensors. This means that when we try to guard on a data-dependent SymNode, we can actually produce a real result. We also produce a warning which you should consult to figure out what the crux points are.
I ran this on vision_maskrcnn. In the baseline (without this mode), the model has 27 graph breaks, resulting in 40 graphs. With this mode on, the model has only 11 graph breaks, resulting in 15 graphs (the remaining graph breaks are due to missing functionality for item() on float tensor and some other Dynamo missing features.) You get a list of things that would have errored like this:
```
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Max(1, u1) < 2) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Eq(Max(1, u1), 1)) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Eq(Max(1, u1), 1)) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Ne(Max(1, u1), 1)) -> False
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Max(1, u0) < 2) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Eq(Max(1, u0), 1)) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Eq(Max(1, u0), 1)) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Ne(Max(1, u0), 1)) -> False
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Max(1, u1) < 2) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Eq(Max(1, u1), 1)) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Eq(Max(1, u1), 1)) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Ne(Max(1, u1), 1)) -> False
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Max(1, u0) < 2) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Eq(Max(1, u0), 1)) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Eq(Max(1, u0), 1)) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Ne(Max(1, u0), 1)) -> False
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Max(1, u1) < 2) -> False
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Eq(Max(1, u1), 1)) -> False
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Ne(Max(1, u1), 1)) -> True
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Max(1, u0) < 2) -> False
WARNING:torch.fx.experimental.symbolic_shapes:propagate_real_tensors evaluate_expr(Eq(Max(1, u0), 1)) -> False
```
Potential later follow ups:
* Improve the warning messages (in particular, should provide user frames)
* GC real tensors when they are no longer needed by tracing. Right now, this will use A LOT of memory, equal to as if your GC was broken and every intermediate tensor was kept live
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/125115
Approved by: https://github.com/IvanKobzarev
This PR has a lot of "draw the rest of the fucking owl" energy. Here's how to break it down.
1. **torch/_inductor/graph.py** - We start by tightening unbacked symbol invariants. Specifically, as we lower FX nodes, we check whether or not every unbacked_binding recorded on the FX node meta, actually ends up getting bound (according to get_unbacked_symbol_defs) in all the buffers generated by the lowering. Hopefully this invariant is self evident. This leads to a lot of failures.
2. **torch/_inductor/ir.py** - Problem 1: There is softness in how Inductor computes defs of unbacked symbols in IR node. Previously, we tried to infer it by looking at the output sizes/strides/etc and see if new unbacked symbols popped up that we hadn't seen in the inputs. I don't know exactly what was buggy about the old code, but sometimes we would fail to notice an unbacked symbol had been bound, or rebind an unbacked symbol multiple times. Fortunately, thanks to the earlier PRs in our stack, we now have a nice list of unbacked symbol bindings from FX, so we now just store it directly on ExternKernel and use it directly to report defs. This has to be done twice: once for FallbackKernel (e.g., nonzero) and once for DynamicScalar (e.g., item) (see also **torch/_inductor/lowering.py**, **torch/_inductor/codegen/wrapper.py** and **torch/_inductor/codegen/cpp_wrapper_cpu.py** for the lowering and codegen changes for item)
* **process_kernel** - Sidequest! It turns out that Inductor lowering can reallocate unbacked symbols. This happens specifically when we repropagate fake tensors through the operator in `process_kernel`. This repropagation process is necessary because Inductor may have changed the strides of input tensors, and it must now recompute the strides so that it can continue to appropriately plan the rest of the lowering process. This is fine: we just make sure we do the rebind unbacked + compute_unbacked_bindings dance we've been doing previously in the PR stack. But instead of putting unbacked_bindings on a new FX node, they go straight into our unbacked_bindings on the Inductor IR node.
* **codegen_unbacked_symbol_defs** - Sidequest! FallbackKernel lowering is done in two steps. First, you emit the FallbackKernel buffer. Then, you emit MultiOutput buffers which actually give access to the individual outputs of FallbackKernel, which may have been multi-output. There is a design decision here: does the FallbackKernel bind the unbacked symbols, or the MultiOutput buffer? Historically, we put the binding on MultiOutput buffer, because it's more convenient: the FallbackKernel buffer is fake, in fact, it doesn't even get a name in C++ codegen. But it's kind of inconsistent with the keypath model that we've been tracking unbacked bindings with: if you have a multi-output node, you'd expect a keypath like `[0].size()[0]` representing the first output's first dimension size. That suggests that it's the FallbackKernel that should define the things. So that was my first implementation. Unfortunately, the C++ codegen is too cursed and I could not understand how to make it work in that case. So now we just unsoundly assume you cannot have multi-output data dependent output, and do the codegen in MultiOutput. There are some comments explaining exactly what we are improperly assuming.
3. **_rename_unbacked_to** in **torch/fx/experimental/symbolic_shapes.py** - Previously, when we renamed unbacked symbols, we clobbered any facts we previously knew about them. So for example, if we had a replacement `u0 -> s0` but then we renamed u0 to u1, we would now setup the replacement `u0 -> u1`, clobbering the old replacement. This apparently didn't matter in earlier PRs in the stack, but with Inductor now on the ball, there were some tests that indicated this was a problem. The solution is easy: if u0 had a preexisting replacement, reapply it to u1. However...
* **torch/_functorch/_aot_autograd/collect_metadata_analysis.py** - When we run forward analysis, this triggers fake tensor repropagation and fresh allocations. Previously, we just cleared out the pending symbols when finished the analysis. But with the change above, this would also migrate replacements to the new symbols... which are now dead. So now we explicitly suppress generation of these symbols with `ignore_fresh_unbacked_symbols` so that no rebinding happens at all.
* **torch/_dynamo/eval_frame.py** - same deal; I just searched for all sites we called clear() on pending
4. The last step is fixing the long tail of extra problems that show up, now that unbacked_bindings are load bearing into Inductor
* **torch/_dynamo/eval_frame.py** - Some of the exports are making copies of nodes without repropagating fake tensors, so in this case, it is important to also copy the `unbacked_bindings` (apparently this didn't matter before without the Inductor changes)
* **torch/_export/pass_base.py** - I discover that this is doing fake tensor repropagation via a test suite failure. Do the same playbook as AOTAutograd: PropagateUnbackedSymInts too! Actually, they also have implemented their own tracer as well, so do the same playbook as proxy_tensor: record unbacked_bindings on the newly traced nodes. UGH code duplication.
* **torch/_subclasses/fake_tensor.py**, **torch/_subclasses/fake_impls.py** (with call site updates at **torch/_functorch/_aot_autograd/traced_function_transforms.py** and **torch/fx/passes/fake_tensor_prop.py**) - What's this new epoch thing? I noticed that sometimes I would be retracing, call nonzero() on a fake tensor, and not allocate a new unbacked symbol. This is actually bad, because if I don't get a new unbacked symbol, I don't know there's a binding site, and `unbacked_bindings` is now missing a binding. The reason for this is memoization: if I reuse the exact same fake tensor on my retrace, it will already have an unbacked symint memoized on it and we will short circuit allocation. Well, that's no good. So I associate the memos with a fake tensor epoch, and every time you start a new fake tensor propagation from scratch, you bump the epoch so that I clear all the memos.
* **torch/_inductor/scheduler.py** - I notice in unit tests that V.current_node is not always set when we call process_kernel. So I save it into the IR node and restore it when we are running `get_estimated_runtime`.
* **torch/fx/experimental/symbolic_shapes.py** - A few things
* **rebind_unbacked** (re **_tensor_version**). Ordinarily, when you have an unbacked SymInt, you persistently hvae it all the way to the end of the program. `_tensor_version` violates this: this generates an unbacked SymInt (for reasons I don't quite understand?) and then gets rid of it later. This triggered an assert violation. I think this op is kind of misusing unbacked SymInt, but I didn't know how to refactor it, so it gets a special case.
* **rebind_unbacked** (re **Simplify SymBool binding**). Ugh, SymBool, what a pain in the butt. I have an assert that you can only rebind unbacked symbol to another unbacked symbol. This assert fails when a boolean is involved, because the result of running keypath on the result is not `u1`, it's `sympy.Piecewise(... sympy.Eq(u1, 1) ...)`. This is actually just `u1`, but Sympy doesn't know it because it doesn't know that `u1` value range is `[0, 1]`. So we manually implement the simplification needed to get the assert to pass.
* **compute_unbacked_bindings** (re **This is pretty fragile**). There is a really funny disaster involving memoization and Inductor process kernel. Ordinarily when I retrace, if there was a memo hit in the old trace, there will be a memo hit in the new trace. However, Inductor process kernel breaks this, because it recreates fake tensor inputs to the operator call from scratch (since they might have different strides), and obviously these tensor inputs don't have the memo from the old one. I tried a little bit to try to manually transplant the memo to the new fake tensor but it seemed hopeless, so I just let the fresh symbol ride, allocating a new unbacked symbol. However, in one of our tests, we rely on knowing that the first nonzero call is equal to the second (memoized) nonzero call. The equality test looked pretty easy to discharge, so I just went ahead and added a deferred runtime assert to this effect and it worked.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/124394
Approved by: https://github.com/jansel
ghstack dependencies: #124310, #124314, #124316
This PR adds support for tensor inputs to `as_nested_tensor()`. The tensor is treated as a batch of consistently-sized constituents. It utilizes `_nested_view_from_values_offsets()` to return a real view that allows for propagating gradients into inputs.
Co-authored-by: voznesenskym <voznesenskym@gmail.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/113280
Approved by: https://github.com/cpuhrsch, https://github.com/soulitzer
ghstack dependencies: #113279
