pytorch/docs/source/onnx_ops.md

torch.onnx.ops

.. automodule:: torch.onnx.ops

Symbolic Operators

Operators that can be used to create any ONNX ops in the FX graph symbolically. These operators do not do actual computation. It's recommended that you used them inside an if torch.onnx.is_in_onnx_export block.

.. autofunction:: torch.onnx.ops.symbolic
.. autofunction:: torch.onnx.ops.symbolic_multi_out

ONNX Operators

The following operators are implemented as native PyTorch ops and can be exported as ONNX operators. They can be used natively in an nn.Module.

For example, you can define a module:

class Model(torch.nn.Module):
    def forward(
        self, input_data, cos_cache_data, sin_cache_data, position_ids_data
    ):
        return torch.onnx.ops.rotary_embedding(
            input_data,
            cos_cache_data,
            sin_cache_data,
            position_ids_data,
        )

and export it to ONNX using:

input_data = torch.rand(2, 3, 4, 8)
position_ids_data = torch.randint(0, 50, (2, 3)).long()
sin_cache_data = torch.rand(50, 4)
cos_cache_data = torch.rand(50, 4)
dynamic_shapes = {
    "input_data": {0: torch.export.Dim.DYNAMIC},
    "cos_cache_data": None,
    "sin_cache_data": None,
    "position_ids_data": {0: torch.export.Dim.DYNAMIC},
}
onnx_program = torch.onnx.export(
    model,
    (input_data, cos_cache_data, sin_cache_data, position_ids_data),
    dynamic_shapes=dynamic_shapes,
    dynamo=True,
    opset_version=23,
)

Printing the ONNX program will show the ONNX operators used in the graph:

<...>

graph(
    name=main_graph,
    inputs=(
        %"input_data"<FLOAT,[s0,3,4,8]>,
        %"cos_cache_data"<FLOAT,[50,4]>,
        %"sin_cache_data"<FLOAT,[50,4]>,
        %"position_ids_data"<INT64,[s0,3]>
    ),
    outputs=(
        %"rotary_embedding"<FLOAT,[s0,3,4,8]>
    ),
) {
    0 |  # rotary_embedding
        %"rotary_embedding"<FLOAT,[s0,3,4,8]> ⬅️ ::RotaryEmbedding(%"input_data", %"cos_cache_data", %"sin_cache_data", %"position_ids_data")
    return %"rotary_embedding"<FLOAT,[s0,3,4,8]>
}

with the corresponding ExportedProgram:

ExportedProgram:

class GraphModule(torch.nn.Module):
    def forward(self, input_data: "f32[s0, 3, 4, 8]", cos_cache_data: "f32[50, 4]", sin_cache_data: "f32[50, 4]", position_ids_data: "i64[s0, 3]"):
        rotary_embedding: "f32[s0, 3, 4, 8]" = torch.ops.onnx.RotaryEmbedding.opset23(input_data, cos_cache_data, sin_cache_data, position_ids_data);  input_data = cos_cache_data = sin_cache_data = position_ids_data = None
        return (rotary_embedding,)

.. autofunction:: torch.onnx.ops.rotary_embedding

ONNX to ATen Decomposition Table

You can use {func}torch.onnx.ops.aten_decompositions to obtain a decomposition table to decompose ONNX operators defined above to ATen operators.

class Model(torch.nn.Module):
    def forward(
        self, input_data, cos_cache_data, sin_cache_data, position_ids_data
    ):
        return torch.onnx.ops.rotary_embedding(
            input_data,
            cos_cache_data,
            sin_cache_data,
            position_ids_data,
        )

model = Model()

ep = torch.export.export(
    model,
    (input_data, cos_cache_data, sin_cache_data, position_ids_data),
)
# The program can be decomposed into aten ops
ep_decomposed = ep.run_decompositions(torch.onnx.ops.aten_decompositions())

.. autofunction:: torch.onnx.ops.aten_decompositions