Is there api to fetch input/output description in c?

[lifang-zhang]

Like the marked information in following picture.

I want the [N, C, H, W] information there.

[mortenwp]

I had a similar question. Basically how do I get the ordering of the data.

I have tried to use to GetDenotationFromTypeInfo in the C api (see code below), but currently I just get the empty string
from that call.

From what I understand of the denotation the ordering of channel, data dimension, and batch dimension are/can be tracked in onnxruntime through the whole graph, so if the user by accident flips the dimension in a wrong way it can be detected... but that is a bit incompatible with that my char* ptr is not being populated

My models has been converted from tensorflow using tf2onnx. But not sure if the denotation info actually are in my onnx file

I don't know if this is of any help :)

best regards
Morten

std::string get_input_denotation(std::size_t idx) const
{
           Ort::TypeInfo typ_info = m_session.GetInputTypeInfo(idx);
           const char* ptr;
           std::size_t len;
           const OrtApi* ort = OrtGetApiBase()->GetApi(ORT_API_VERSION);
           OrtStatus* stat(ort->GetDenotationFromTypeInfo(typ_info,&ptr,&len));
           if(stat==nullptr)
            return std::string(ptr);
          return std::string();
}

[lifang-zhang]

Oh, I might be wrong, I am guessing GetDenotationFromTypeInfo is to get denotation of type instead of dimention, so can use print(onnx_model.graph.input[0].type) to check if there is any denotation.

[mortenwp]

Thanks, I will try that. I have asked on the tf2onnx project if denotation is supported when they convert from tf or keras to onnx.
I will try the python route.

There seams to be a whole set of ModelMetaDataGet functions i.e. ModelMetaDataGetGraphDescription in the C-api. I don't know if one of these could be used to extract the information from your model?

[lifang-zhang]

Yes, I have used ModelMetaDataGet to get the metadata about the model. But the doc_string is under graph, so it does not belong to metadata :(

And not all metadata can be fetched in onnxruntime.

[lifang-zhang]

In my model canny.onnx, the put author and license in the metadata_props, so I fetch it through function ModelMetadataLookupCustomMetadataMap()

[mortenwp]

ModelMetadataGetGraphDescription says it returns the description of the graph present in the model (doc_string field of the GraphProto message within the ModelProto message). If it doesn't exist, an empty string will be returned. Isn't that what you after?