Files
cutlass/examples/python/CuTeDSL/cute/torch_fake_tensor.py
Junkai-Wu b1d6e2c9b3 v4.3 update. (#2709)
* v4.3 update.

* Update the cute_dsl_api changelog's doc link

* Update version to 4.3.0

* Update the example link

* Update doc to encourage user to install DSL from requirements.txt

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Co-authored-by: Larry Wu <larwu@nvidia.com>
2025-10-21 14:26:30 -04:00

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3.0 KiB
Python

# Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: BSD-3-Clause
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import torch
import cutlass.cute as cute
from cutlass.cute.runtime import from_dlpack
"""Example demonstrating how to use CuTe with PyTorch's FakeTensor mode.
This example shows how to:
1. Use PyTorch's FakeTensor mode to compile a CuTe function without real data
2. Execute the compiled function on real data later
FakeTensor mode allows compiling code without allocating real memory, which is useful
for ahead-of-time compilation scenarios. The compiled function can then be executed
on real tensors that match the expected shapes and dtypes.
Primary goals of this example are to demonstrate: How to use PyTorch's FakeTensor mode with CuTe
to enable ahead-of-time compilation without real data allocation.
The example:
1. Creates a fake tensor in PyTorch using FakeTensor mode
2. Compiles a CuTe function using the fake tensor without allocating real memory
3. Creates a real tensor with matching shape and dtype
4. Executes the compiled function on the real tensor
To run this example:
.. code-block:: bash
python examples/cute/torch_fake_tensor.py
"""
@cute.jit
def print_tensor(t: cute.Tensor):
cute.print_tensor(t)
if __name__ == "__main__":
from torch._subclasses.fake_tensor import FakeTensorMode
shape = (3, 4)
with FakeTensorMode():
fake_tensor = torch.zeros(shape, dtype=torch.float32)
compiled_fn = cute.compile(print_tensor, from_dlpack(fake_tensor))
real_tensor = torch.randn(shape, dtype=torch.float32)
compiled_fn(from_dlpack(real_tensor))