onnxruntime C++ how to get outputTensor dynamic shape? - c++

Question

Try using something like this:
std::vector<Ort::Value> ort_inputs;
for (int i = 0; i < inputNames.size(); ++i) {
ort_inputs.emplace_back(Ort::Value::CreateTensor<float>(
memoryInfo, static_cast<float *>(inputs[i].data), inputs[i].get_size(),
inputShapes[i].data(), inputShapes[i].size()));
}
std::vector<Ort::Value> outputTensors =
session.Run(Ort::RunOptions{nullptr}, inputNames.data(),
ort_inputs.data(), 1, outputNames.data(), outputNames.size());
Now, my model is like this:
yolox_tiny_cpunms.onnx Detail
╭──────────────┬────────────────────────────────┬────────────────────────┬───────────────╮
│ Name │ Shape │ Input/Output │ Dtype │
├──────────────┼────────────────────────────────┼────────────────────────┼───────────────┤
│ input │ [1, 3, 416, 416] │ input │ float32 │
│ boxes │ [1, -1, -1] │ output │ float32 │
│ scores │ [1, -1] │ output │ float32 │
│ labels │ [1, -1] │ output │ int64 │
╰──────────────┴────────────────────────────────┴────────────────────────┴───────────────╯
As you can see, the output is dynamic, but C++ code output Tensor give me shape [1, 0, 4]
, [1, 0], [1,0]
How can I get the output shape in. C++?

Answer 1

I get the output shape in C++ like this
auto outputTensor = session.Run(runOptions, inputNames.data(), &inputTensor, 1, outputNames.data(), 1);
assert(outputTensor.size() == 1 && outpuTensor.front().IsTensor());
if (outputTensor[0].IsTensor())
{
auto outputInfo = outputTensor[0].GetTensorTypeAndShapeInfo();
std::cout << "GetElementType: " << outputInfo.GetElementType() << "\n";
std::cout << "Dimensions of the output: " << outputInfo.GetShape().size() << "\n";
std::cout << "Shape of the output: ";
for (unsigned int shapeI = 0; shapeI < outputInfo.GetShape().size(); shapeI++)
std::cout << outputInfo.GetShape()[shapeI] << ", ";
}