ONNXRuntime.h

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/*
 * ONNXRuntime.h
 *
 * A convenience wrapper of the ONNXRuntime C++ API.
 * Based on https://github.com/microsoft/onnxruntime/blob/master/csharp/test/Microsoft.ML.OnnxRuntime.EndToEndTests.Capi/CXX_Api_Sample.cpp.
 *
 *  Created on: Jun 28, 2019
 *      Author: hqu
 */

#ifndef PHYSICSTOOLS_ONNXRUNTIME_INTERFACE_ONNXRUNTIME_H_
#define PHYSICSTOOLS_ONNXRUNTIME_INTERFACE_ONNXRUNTIME_H_

#include <vector>
#include <map>
#include <string>
#include <memory>

#include "onnxruntime/core/session/onnxruntime_cxx_api.h"

namespace cms::Ort {

  typedef std::vector<std::vector<float>> FloatArrays;

  enum class Backend {
    cpu,
    cuda,
  };

  class ONNXRuntime {
  public:
    ONNXRuntime(const std::string& model_path, const ::Ort::SessionOptions* session_options = nullptr);
    ONNXRuntime(const ONNXRuntime&) = delete;
    ONNXRuntime& operator=(const ONNXRuntime&) = delete;
    ~ONNXRuntime();

    static ::Ort::SessionOptions defaultSessionOptions(Backend backend = Backend::cpu);

    // Run inference and get outputs
    // input_names: list of the names of the input nodes.
    // input_values: list of input arrays for each input node. The order of `input_values` must match `input_names`.
    // input_shapes: list of `int64_t` arrays specifying the shape of each input node. Can leave empty if the model does not have dynamic axes.
    // output_names: names of the output nodes to get outputs from. Empty list means all output nodes.
    // batch_size: number of samples in the batch. Each array in `input_values` must have a shape layout of (batch_size, ...).
    // Returns: a std::vector<std::vector<float>>, with the order matched to `output_names`.
    // When `output_names` is empty, will return all outputs ordered as in `getOutputNames()`.
    FloatArrays run(const std::vector<std::string>& input_names,
                    FloatArrays& input_values,
                    const std::vector<std::vector<int64_t>>& input_shapes = {},
                    const std::vector<std::string>& output_names = {},
                    int64_t batch_size = 1) const;

    // Get a list of names of all the output nodes
    const std::vector<std::string>& getOutputNames() const;

    // Get the shape of a output node
    // The 0th dim depends on the batch size, therefore is set to -1
    const std::vector<int64_t>& getOutputShape(const std::string& output_name) const;

  private:
    static const ::Ort::Env env_;
    std::unique_ptr<::Ort::Session> session_;

    std::vector<std::string> input_node_strings_;
    std::vector<const char*> input_node_names_;
    std::map<std::string, std::vector<int64_t>> input_node_dims_;

    std::vector<std::string> output_node_strings_;
    std::vector<const char*> output_node_names_;
    std::map<std::string, std::vector<int64_t>> output_node_dims_;
  };

}  // namespace cms::Ort

#endif /* PHYSICSTOOLS_ONNXRUNTIME_INTERFACE_ONNXRUNTIME_H_ */