optimized_model_str = C.optimize(model_str, passes) IndexError: _Map_base::at

问题场景

pytorch->onnx->caffe2出现的问题

在onnx->caffe2时会出现

Traceback (most recent call last):
  File "/usr/local/bin/convert-onnx-to-caffe2", line 8, in <module>
    sys.exit(onnx_to_caffe2())
  File "/usr/local/lib/python3.6/dist-packages/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/lib/python3.6/dist-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python3.6/dist-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python3.6/dist-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python3.6/dist-packages/caffe2/python/onnx/bin/conversion.py", line 87, in onnx_to_caffe2
    init_net, predict_net = c2.onnx_graph_to_caffe2_net(onnx_model_proto)
  File "/usr/local/lib/python3.6/dist-packages/caffe2/python/onnx/backend.py", line 921, in onnx_graph_to_caffe2_net
    return cls._onnx_model_to_caffe2_net(model, device=device, opset_version=opset_version, include_initializers=True)
  File "/usr/local/lib/python3.6/dist-packages/caffe2/python/onnx/backend.py", line 876, in _onnx_model_to_caffe2_net
    onnx_model = onnx.utils.polish_model(onnx_model)
  File "/usr/local/lib/python3.6/dist-packages/onnx/utils.py", line 21, in polish_model
    model = onnx.optimizer.optimize(model)
  File "/usr/local/lib/python3.6/dist-packages/onnx/optimizer.py", line 55, in optimize
    optimized_model_str = C.optimize(model_str, passes)
IndexError: _Map_base::at

修复

在pytorch导出的时候设置参数

torch.onnx._export(model, x, "model.onnx", export_params=True, keep_initializers_as_inputs=True)

原因

原因是导出模型时使用了CPU，导入caffe2时默认使用CUDA，导致错误。

参考地址
https://github.com/onnx/onnx/issues/1385