How to Export 'ONNX' Model?

[fspanda]

Hi. Thanks to this code, I was able to write a multi-label classification model well.
By the way, can you tell me how to export the model made like this using torch.onnx? An error occurred when I used the normal torch.onnx.export method.

My code :

test_comment="hello"  
encoding = tokenizer.encode_plus(
    test_comment,
    add_special_tokens=True,
    max_length=63,
    return_token_type_ids=False,
    padding="max_length",
    return_attention_mask=True,
    return_tensors='pt',
  )



torch.onnx.export(trained_model,
                    (encoding["input_ids"], encoding["attention_mask"]),
                    'model.onnx',
                    export_params=True,
                    do_constant_folding=True,
                    opset_version=11,
                    input_names=['input_ids', 'attention_mask'],
                    output_names=['output'],
)

error :

RuntimeError                              Traceback (most recent call last)
<ipython-input-49-9c2e1e064898> in <module>
----> 1 torch.onnx.export(trained_model,
      2                     (encoding["input_ids"], encoding["attention_mask"]),
      3                     'model.onnx',
      4                     export_params=True,
      5                     do_constant_folding=True,

~/anaconda3/envs/myenv1/lib/python3.8/site-packages/torch/onnx/__init__.py in export(model, args, f, export_params, verbose, training, input_names, output_names, aten, export_raw_ir, operator_export_type, opset_version, _retain_param_name, do_constant_folding, example_outputs, strip_doc_string, dynamic_axes, keep_initializers_as_inputs, custom_opsets, enable_onnx_checker, use_external_data_format)
    273 
    274     from torch.onnx import utils
--> 275     return utils.export(model, args, f, export_params, verbose, training,
    276                         input_names, output_names, aten, export_raw_ir,
    277                         operator_export_type, opset_version, _retain_param_name,

~/anaconda3/envs/myenv1/lib/python3.8/site-packages/torch/onnx/utils.py in export(model, args, f, export_params, verbose, training, input_names, output_names, aten, export_raw_ir, operator_export_type, opset_version, _retain_param_name, do_constant_folding, example_outputs, strip_doc_string, dynamic_axes, keep_initializers_as_inputs, custom_opsets, enable_onnx_checker, use_external_data_format)
     86         else:
     87             operator_export_type = OperatorExportTypes.ONNX
---> 88     _export(model, args, f, export_params, verbose, training, input_names, output_names,
     89             operator_export_type=operator_export_type, opset_version=opset_version,
     90             _retain_param_name=_retain_param_name, do_constant_folding=do_constant_folding,

~/anaconda3/envs/myenv1/lib/python3.8/site-packages/torch/onnx/utils.py in _export(model, args, f, export_params, verbose, training, input_names, output_names, operator_export_type, export_type, example_outputs, opset_version, _retain_param_name, do_constant_folding, strip_doc_string, dynamic_axes, keep_initializers_as_inputs, fixed_batch_size, custom_opsets, add_node_names, enable_onnx_checker, use_external_data_format, onnx_shape_inference)
    687 
...
    128             wrapper,
    129             in_vars + module_state,

RuntimeError: output 1 (0
[ CPULongType{} ]) of traced region did not have observable data dependence with trace inputs; this probably indicates your program cannot be understood by the tracer.

Thank you in advance for your reply.