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import nnvm.frontend

def import(..., input_format='onnx'):
  # convert from onnx to nnvm graph
  nnvm_graph, params = nnvm.frontend.from_onnx(...) # Exists
  # convert fron nnvm graph to mxnet graph
  mxnet_graph, params = nnvm.frontend.to_mxnet(...) # Need to implement
  return mxnet_graph, params

def export(..., output_format='onnx'):
  # convert from mxnet to nnvm graph
  nnvm_graph, params = nnvm.frontend.from_mxnet(...) # Exists
  # convert fron nnvm graph to onnx proto format
  onnx_proto = nnvm.frontend.to_onnx(...) # Need to implement
  return onnx_proto

Suggested approach:

As a middle ground for both of the above implementation choices, I propose to take the first approach and implement MXNet->ONNX conversion for export functionality and if someone wants to take advantage of NNVM/TVM optimized engine for their usage, they can do it by leveraging import functionality provided in NNVM/TVM package.

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