cpp-package/include/mxnet-cpp/contrib.h

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/*!
 * \file contrib.h
 * \brief utility function to enable some contrib features
 * \author Haohuan Wang
 */
#ifndef MXNET_CPP_CONTRIB_H_
#define MXNET_CPP_CONTRIB_H_

#include <iostream>
#include <string>
#include <map>
#include <vector>
#include "mxnet-cpp/symbol.h"

namespace mxnet {
namespace cpp {
namespace details {

/*!
 * split a string with the given delimiter
 * @param str string to be parsed
 * @param delimiter delimiter
 * @return delimited list of string
 */
inline std::vector<std::string> split(const std::string& str, const std::string& delimiter) {
  std::vector<std::string> splitted;
  size_t last = 0;
  size_t next = 0;
  while ((next = str.find(delimiter, last)) != std::string::npos) {
    splitted.push_back(str.substr(last, next - last));
    last = next + 1;
  }
  splitted.push_back(str.substr(last));
  return splitted;
}

}  // namespace details

namespace contrib {

// needs to be same with
//   https://github.com/apache/mxnet/blob/1c874cfc807cee755c38f6486e8e0f4d94416cd8/src/operator/subgraph/tensorrt/tensorrt-inl.h#L190
static const std::string TENSORRT_SUBGRAPH_PARAM_IDENTIFIER = "subgraph_params_names";  // NOLINT
// needs to be same with
//   https://github.com/apache/mxnet/blob/master/src/operator/subgraph/tensorrt/tensorrt.cc#L244
static const std::string TENSORRT_SUBGRAPH_PARAM_PREFIX = "subgraph_param_";  // NOLINT
/*!
 * this is a mimic to
 * https://github.com/apache/mxnet/blob/master/python/mxnet/contrib/tensorrt.py#L37
 * @param symbol symbol that already called subgraph api
 * @param argParams original arg params, params needed by tensorrt will be removed after calling
 * this function
 * @param auxParams original aux params, params needed by tensorrt will be removed after calling
 * this function
 */
inline void InitTensorRTParams(const mxnet::cpp::Symbol& symbol,
                               std::map<std::string, mxnet::cpp::NDArray>* argParams,
                               std::map<std::string, mxnet::cpp::NDArray>* auxParams) {
  mxnet::cpp::Symbol internals = symbol.GetInternals();
  mx_uint numSymbol            = internals.GetNumOutputs();
  for (mx_uint i = 0; i < numSymbol; ++i) {
    std::map<std::string, std::string> attrs = internals[i].ListAttributes();
    if (attrs.find(TENSORRT_SUBGRAPH_PARAM_IDENTIFIER) != attrs.end()) {
      std::string new_params_names;
      std::map<std::string, mxnet::cpp::NDArray> tensorrtParams;
      std::vector<std::string> keys =
          details::split(attrs[TENSORRT_SUBGRAPH_PARAM_IDENTIFIER], ";");
      for (const auto& key : keys) {
        if (argParams->find(key) != argParams->end()) {
          new_params_names += key + ";";
          tensorrtParams[TENSORRT_SUBGRAPH_PARAM_PREFIX + key] = (*argParams)[key];
          argParams->erase(key);
        } else if (auxParams->find(key) != auxParams->end()) {
          new_params_names += key + ";";
          tensorrtParams[TENSORRT_SUBGRAPH_PARAM_PREFIX + key] = (*auxParams)[key];
          auxParams->erase(key);
        }
      }
      std::map<std::string, std::string> new_attrs = {};
      for (const auto& kv : tensorrtParams) {
        // passing the ndarray address into TRT node attributes to get the weight
        uint64_t address    = reinterpret_cast<uint64_t>(kv.second.GetHandle());
        new_attrs[kv.first] = std::to_string(address);
      }
      if (!new_attrs.empty()) {
        internals[i].SetAttributes(new_attrs);
        internals[i].SetAttribute(TENSORRT_SUBGRAPH_PARAM_IDENTIFIER,
                                  new_params_names.substr(0, new_params_names.length() - 1));
      }
    }
  }
}

}  // namespace contrib
}  // namespace cpp
}  // namespace mxnet

#endif  // MXNET_CPP_CONTRIB_H_