Onnxruntime c接口说明及 动态调用示例

Onnxruntime 是一个用于运行机器学习模型的开源框架，它支持多种语言，包括 C++、Python、C#、Java 等。下面是 Onnxruntime 的 C 接口说明及动态调用示例：

1. 引入头文件

#include "onnxruntime_c_api.h"

2. 创建一个 Onnxruntime 的 session

OrtEnv* env;
OrtCreateEnv(ORT_LOGGING_LEVEL_WARNING, "test", &env);

OrtSessionOptions* session_options;
OrtCreateSessionOptions(&session_options);
OrtSession* session;
OrtCreateSession(env, "model.onnx", session_options, &session);

3. 获取输入和输出名称及形状

size_t num_input_nodes;
OrtStatus* status = OrtSessionGetInputCount(session, &num_input_nodes);
OrtStatus* status = OrtSessionGetOutputCount(session, &num_output_nodes);

OrtAllocator* allocator;
OrtCreateDefaultAllocator(&allocator);

OrtTypeInfo* type_info;
OrtSessionGetInputTypeInfo(session, 0, &type_info);
const OrtTensorTypeAndShapeInfo* tensor_info;
OrtGetTensorTypeAndShape(type_info, &tensor_info);

size_t num_dims = OrtGetNumOfDimensions(tensor_info);
int64_t* dims = (int64_t*)malloc(num_dims * sizeof(int64_t));
OrtGetDimensions(tensor_info, dims, num_dims);

char* input_name = NULL;
OrtSessionGetInputName(session, 0, allocator, &input_name);

OrtGetTensorElementType(tensor_info);

4. 准备输入数据

float* input = (float*)malloc(num_dims * sizeof(float));
// fill input data

5. 运行 session

OrtValue* input_tensor;
OrtCreateTensorWithDataAsOrtValue(allocator, input, num_dims * sizeof(float), dims, num_dims, ONNX_TENSOR_ELEMENT_DATA_TYPE_FLOAT, &input_tensor);

const char* const input_names[] = {input_name};
OrtValue* input_tensors[] = {input_tensor};

OrtValue* output_tensor;
OrtSessionRun(session, NULL, input_names, input_tensors, 1, output_names, 1, &output_tensor);

float* output = (float*)OrtGetTensorMutableData(output_tensor);
// process output data

OrtReleaseValue(output_tensor);
OrtReleaseValue(input_tensor);

6. 释放资源

OrtReleaseTypeInfo(type_info);
OrtReleaseSession(session);
OrtReleaseSessionOptions(session_options);
OrtReleaseEnv(env);
free(input);
free(dims);