src/engine/engine_impl.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.
 */

/*!
 * Copyright (c) 2015 by Contributors
 * \file engine_impl.h
 * \brief Internal implementation header of engine components.
 */
#ifndef MXNET_ENGINE_ENGINE_IMPL_H_
#define MXNET_ENGINE_ENGINE_IMPL_H_

#include <mxnet/engine.h>

/*! \brief MACRO on whether or not enable debug option*/
#define ENGINE_DEBUG 0

namespace mxnet {
namespace engine {

/*! \brief base class of engine operators, used for type checking */
struct Opr {
#if ENGINE_DEBUG
  virtual ~Opr() = default;
#endif
  /*!
   * \brief cast variable to derived type T
   * \tparam T the type we want to cast into.
   * \return A casted variable.
   */
  template <typename T>
  inline T* Cast();
};  // struct Opr

// implementation of the inline functions
template <typename T>
inline T* Var::Cast() {
  static_assert(std::is_base_of<Var, T>::value,
                "must inherit `mxnet::engine::Var`");
#if ENGINE_DEBUG
  return dynamic_cast<T*>(this);
#else
  return static_cast<T*>(this);
#endif
}

template <typename T>
inline T* Opr::Cast() {
  static_assert(std::is_base_of<Opr, T>::value,
                "must inherit `mxnet::engine::Opr`");
#if ENGINE_DEBUG
  return dynamic_cast<T*>(this);
#else
  return static_cast<T*>(this);
#endif
}

/*! \brief Maximum number of GPUs */
static constexpr std::size_t kMaxNumGPUs = 16;

// predeclare factory function for each type of engine
/*! \return NaiveEngine instance */
Engine *CreateNaiveEngine();
#if MXNET_PREDICT_ONLY == 0
/*! \return ThreadedEnginePooled instance */
Engine *CreateThreadedEnginePooled();
/*! \return ThreadedEnginePerDevie instance */
Engine *CreateThreadedEnginePerDevice();
#endif
}  // namespace engine
}  // namespace mxnet
#endif  // MXNET_ENGINE_ENGINE_IMPL_H_