Hi, It seems that there is something wrong with the format of the input data.
I use input_data = [torch.arange(4).reshape(2,2) for _ in range(3)] and
torch.onnx.export(
    model,
    tuple(input_data),
    onnx_io,
    verbose=False,
    input_names=None,
    output_names=None,
)

instead, and it works fine.