Export model to ONNX

[suyuzhang]

Hi

I try to convert the lite-transformer model to ONNX, but I catch a lot of problems during this process.
I can't move forward with errors. Does anybody have a positive experience in export this model to ONNX?

Error message:

Traceback (most recent call last):
  File "generate.py", line 202, in <module>
    cli_main()
  File "generate.py", line 198, in cli_main
    main(args)
  File "generate.py", line 110, in main
    torch.onnx.export(model, args=(dummy_1, dummy_3, dummy_2), f='output.onnx', keep_initializers_as_inputs=True, opset_version=9, operator_export_type=torch.onnx.OperatorExportTypes.ONNX_ATEN_FALLBACK)
  File "/opt/conda/lib/python3.6/site-packages/torch/onnx/__init__.py", line 230, in export
    custom_opsets, enable_onnx_checker, use_external_data_format)
  File "/opt/conda/lib/python3.6/site-packages/torch/onnx/utils.py", line 92, in export
    use_external_data_format=use_external_data_format)
  File "/opt/conda/lib/python3.6/site-packages/torch/onnx/utils.py", line 538, in _export
    fixed_batch_size=fixed_batch_size)
  File "/opt/conda/lib/python3.6/site-packages/torch/onnx/utils.py", line 374, in _model_to_graph
    graph, torch_out = _trace_and_get_graph_from_model(model, args)
  File "/opt/conda/lib/python3.6/site-packages/torch/onnx/utils.py", line 327, in _trace_and_get_graph_from_model
    torch.jit._get_trace_graph(model, args, strict=False, _force_outplace=False, _return_inputs_states=True)
  File "/opt/conda/lib/python3.6/site-packages/torch/jit/__init__.py", line 135, in _get_trace_graph
    outs = ONNXTracedModule(f, strict, _force_outplace, return_inputs, _return_inputs_states)(*args, **kwargs)
  File "/opt/conda/lib/python3.6/site-packages/torch/nn/modules/module.py", line 726, in _call_impl
    result = self.forward(*input, **kwargs)
  File "/opt/conda/lib/python3.6/site-packages/torch/jit/_trace.py", line 116, in forward
    self._force_outplace,
  File "/opt/conda/lib/python3.6/site-packages/torch/jit/_trace.py", line 105, in wrapper
    out_vars, _ = _flatten(outs)
RuntimeError: Only tuples, lists and Variables supported as JIT inputs/outputs. Dictionaries and strings are also accepted but their usage is not recommended. But got unsupported type NoneType

Thanks.

[Michaelvll]

Thank you for asking! We did not support the convention of the model to ONNX format. We are appreciated it if anyone would like to contribute for that. ;)