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//                        Kokkos v. 3.0
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#ifndef KOKKOS_OPENMPEXEC_HPP
#define KOKKOS_OPENMPEXEC_HPP

#include <Kokkos_Macros.hpp>
#if defined(KOKKOS_ENABLE_OPENMP)

#if !defined(_OPENMP) && !defined(__CUDA_ARCH__)
#error \
    "You enabled Kokkos OpenMP support without enabling OpenMP in the compiler!"
#endif

#include <Kokkos_OpenMP.hpp>

#include <impl/Kokkos_Traits.hpp>
#include <impl/Kokkos_HostThreadTeam.hpp>

#include <Kokkos_Atomic.hpp>

#include <Kokkos_UniqueToken.hpp>

#include <iostream>
#include <sstream>
#include <fstream>

#include <omp.h>

//----------------------------------------------------------------------------
//----------------------------------------------------------------------------

namespace Kokkos {
namespace Impl {

class OpenMPExec;

extern int g_openmp_hardware_max_threads;

extern __thread int t_openmp_hardware_id;
extern __thread OpenMPExec* t_openmp_instance;

//----------------------------------------------------------------------------
/** \brief  Data for OpenMP thread execution */

class OpenMPExec {
 public:
  friend class Kokkos::OpenMP;

  enum { MAX_THREAD_COUNT = 512 };

  void clear_thread_data();

  static void validate_partition(const int nthreads, int& num_partitions,
                                 int& partition_size);

 private:
  OpenMPExec(int arg_pool_size)
      : m_pool_size{arg_pool_size}, m_level{omp_get_level()}, m_pool() {}

  ~OpenMPExec() { clear_thread_data(); }

  int m_pool_size;
  int m_level;

  HostThreadTeamData* m_pool[MAX_THREAD_COUNT];

 public:
  static void verify_is_master(const char* const);

  void resize_thread_data(size_t pool_reduce_bytes, size_t team_reduce_bytes,
                          size_t team_shared_bytes, size_t thread_local_bytes);

  inline HostThreadTeamData* get_thread_data() const noexcept {
    return m_pool[m_level == omp_get_level() ? 0 : omp_get_thread_num()];
  }

  inline HostThreadTeamData* get_thread_data(int i) const noexcept {
    return m_pool[i];
  }
};

}  // namespace Impl
}  // namespace Kokkos

//----------------------------------------------------------------------------
//----------------------------------------------------------------------------

namespace Kokkos {

inline
#ifdef KOKKOS_ENABLE_DEPRECATED_CODE
    bool
    OpenMP::is_initialized() noexcept
#else
    bool
    OpenMP::impl_is_initialized() noexcept
#endif
{
  return Impl::t_openmp_instance != nullptr;
}

inline bool OpenMP::in_parallel(OpenMP const&) noexcept {
  // t_openmp_instance is only non-null on a master thread
  return !Impl::t_openmp_instance ||
         Impl::t_openmp_instance->m_level < omp_get_level();
}

inline
#ifdef KOKKOS_ENABLE_DEPRECATED_CODE
    int
    OpenMP::thread_pool_size() noexcept
#else
    int
    OpenMP::impl_thread_pool_size() noexcept
#endif
{
  return OpenMP::in_parallel() ? omp_get_num_threads()
                               : Impl::t_openmp_instance->m_pool_size;
}

KOKKOS_INLINE_FUNCTION
#ifdef KOKKOS_ENABLE_DEPRECATED_CODE
int OpenMP::thread_pool_rank() noexcept
#else
int OpenMP::impl_thread_pool_rank() noexcept
#endif
{
#if defined(KOKKOS_ACTIVE_EXECUTION_MEMORY_SPACE_HOST)
  return Impl::t_openmp_instance ? 0 : omp_get_thread_num();
#else
  return -1;
#endif
}

inline void OpenMP::impl_static_fence(OpenMP const& /*instance*/) noexcept {}

#ifdef KOKKOS_ENABLE_DEPRECATED_CODE
inline void OpenMP::fence(OpenMP const& instance) noexcept {}
#endif

inline bool OpenMP::is_asynchronous(OpenMP const& /*instance*/) noexcept {
  return false;
}

template <typename F>
void OpenMP::partition_master(F const& f, int num_partitions,
                              int partition_size) {
#if _OPENMP >= 201811
  if (omp_get_max_active_levels() > 1) {
#else
  if (omp_get_nested() > 1) {
#endif
    using Exec = Impl::OpenMPExec;

    Exec* prev_instance = Impl::t_openmp_instance;

    Exec::validate_partition(prev_instance->m_pool_size, num_partitions,
                             partition_size);

    OpenMP::memory_space space;

#pragma omp parallel num_threads(num_partitions)
    {
      void* ptr = nullptr;
      try {
        ptr = space.allocate(sizeof(Exec));
      } catch (
          Kokkos::Experimental::RawMemoryAllocationFailure const& failure) {
        // For now, just rethrow the error message the existing way
        Kokkos::Impl::throw_runtime_exception(failure.get_error_message());
      }

      Impl::t_openmp_instance = new (ptr) Exec(partition_size);

      size_t pool_reduce_bytes  = 32 * partition_size;
      size_t team_reduce_bytes  = 32 * partition_size;
      size_t team_shared_bytes  = 1024 * partition_size;
      size_t thread_local_bytes = 1024;

      Impl::t_openmp_instance->resize_thread_data(
          pool_reduce_bytes, team_reduce_bytes, team_shared_bytes,
          thread_local_bytes);

      omp_set_num_threads(partition_size);
      f(omp_get_thread_num(), omp_get_num_threads());

      Impl::t_openmp_instance->~Exec();
      space.deallocate(Impl::t_openmp_instance, sizeof(Exec));
      Impl::t_openmp_instance = nullptr;
    }

    Impl::t_openmp_instance = prev_instance;
  } else {
    // nested openmp not enabled
    f(0, 1);
  }
}

namespace Experimental {

template <>
class MasterLock<OpenMP> {
 public:
  void lock() { omp_set_lock(&m_lock); }
  void unlock() { omp_unset_lock(&m_lock); }
  bool try_lock() { return static_cast<bool>(omp_test_lock(&m_lock)); }

  MasterLock() { omp_init_lock(&m_lock); }
  ~MasterLock() { omp_destroy_lock(&m_lock); }

  MasterLock(MasterLock const&) = delete;
  MasterLock(MasterLock&&)      = delete;
  MasterLock& operator=(MasterLock const&) = delete;
  MasterLock& operator=(MasterLock&&) = delete;

 private:
  omp_lock_t m_lock;
};

template <>
class UniqueToken<OpenMP, UniqueTokenScope::Instance> {
 public:
  using execution_space = OpenMP;
  using size_type       = int;

  /// \brief create object size for concurrency on the given instance
  ///
  /// This object should not be shared between instances
  UniqueToken(execution_space const& = execution_space()) noexcept {}

  /// \brief upper bound for acquired values, i.e. 0 <= value < size()
  KOKKOS_INLINE_FUNCTION
  int size() const noexcept {
#if defined(KOKKOS_ACTIVE_EXECUTION_MEMORY_SPACE_HOST)
#if defined(KOKKOS_ENABLE_DEPRECATED_CODE)
    return Kokkos::OpenMP::thread_pool_size();
#else
    return Kokkos::OpenMP::impl_thread_pool_size();
#endif
#else
    return 0;
#endif
  }

  /// \brief acquire value such that 0 <= value < size()
  KOKKOS_INLINE_FUNCTION
  int acquire() const noexcept {
#if defined(KOKKOS_ACTIVE_EXECUTION_MEMORY_SPACE_HOST)
#if defined(KOKKOS_ENABLE_DEPRECATED_CODE)
    return Kokkos::OpenMP::thread_pool_rank();
#else
    return Kokkos::OpenMP::impl_thread_pool_rank();
#endif
#else
    return 0;
#endif
  }

  /// \brief release a value acquired by generate
  KOKKOS_INLINE_FUNCTION
  void release(int) const noexcept {}
};

template <>
class UniqueToken<OpenMP, UniqueTokenScope::Global> {
 public:
  using execution_space = OpenMP;
  using size_type       = int;

  /// \brief create object size for concurrency on the given instance
  ///
  /// This object should not be shared between instances
  UniqueToken(execution_space const& = execution_space()) noexcept {}

  /// \brief upper bound for acquired values, i.e. 0 <= value < size()
  KOKKOS_INLINE_FUNCTION
  int size() const noexcept {
#if defined(KOKKOS_ACTIVE_EXECUTION_MEMORY_SPACE_HOST)
    return Kokkos::Impl::g_openmp_hardware_max_threads;
#else
    return 0;
#endif
  }

  /// \brief acquire value such that 0 <= value < size()
  KOKKOS_INLINE_FUNCTION
  int acquire() const noexcept {
#if defined(KOKKOS_ACTIVE_EXECUTION_MEMORY_SPACE_HOST)
    return Kokkos::Impl::t_openmp_hardware_id;
#else
    return 0;
#endif
  }

  /// \brief release a value acquired by generate
  KOKKOS_INLINE_FUNCTION
  void release(int) const noexcept {}
};

}  // namespace Experimental

inline
#ifdef KOKKOS_ENABLE_DEPRECATED_CODE
    int
    OpenMP::thread_pool_size(int depth)
#else
    int
    OpenMP::impl_thread_pool_size(int depth)
#endif
{
  return depth < 2
#ifdef KOKKOS_ENABLE_DEPRECATED_CODE
             ? thread_pool_size()
#else
             ? impl_thread_pool_size()
#endif
             : 1;
}

KOKKOS_INLINE_FUNCTION
#ifdef KOKKOS_ENABLE_DEPRECATED_CODE
int OpenMP::hardware_thread_id() noexcept
#else
int OpenMP::impl_hardware_thread_id() noexcept
#endif
{
#if defined(KOKKOS_ACTIVE_EXECUTION_MEMORY_SPACE_HOST)
  return Impl::t_openmp_hardware_id;
#else
  return -1;
#endif
}

inline
#ifdef KOKKOS_ENABLE_DEPRECATED_CODE
    int
    OpenMP::max_hardware_threads() noexcept
#else
    int
    OpenMP::impl_max_hardware_threads() noexcept
#endif
{
  return Impl::g_openmp_hardware_max_threads;
}

}  // namespace Kokkos

#endif
#endif /* #ifndef KOKKOS_OPENMPEXEC_HPP */
