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//======================================================================================================================
//
// This file is part of waLBerla. waLBerla is free software: you can
// redistribute it and/or modify it under the terms of the GNU General Public
// License as published by the Free Software Foundation, either version 3 of
// the License, or (at your option) any later version.
//
// waLBerla is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with waLBerla (see COPYING.txt). If not, see <http://www.gnu.org/licenses/>.
//
//! \file UniqueID.h
//! \ingroup core
//! \author Klaus Iglberger
//! \author Sebastian Eibl <sebastian.eibl@fau.de>
//
//======================================================================================================================
#pragma once
//*************************************************************************************************
// Includes
//*************************************************************************************************
#include <stdexcept>
#include <core/mpi/MPIManager.h>
#include <core/debug/Debug.h>
#include <core/NonCreateable.h>
#include <core/DataTypes.h>
namespace walberla {
//=================================================================================================
//
// CLASS DEFINITION
//
//=================================================================================================
//*************************************************************************************************
/*!\brief Generation of unique IDs in MPI environments.
* \ingroup core
*
* The UniqueID class is responsible for the generation of unique system IDs even during an MPI
* parallel execution. The unqiue ID is composed from the number of locally generated objects
* of type \a T and the rank of the local MPI process.
*/
template< typename T >
class UniqueID : private NonCreateable
{
public:
//**Utility functions***************************************************************************
/*!\name Utility functions */
//@{
static inline id_t create();
static inline id_t createGlobal();
static inline id_t invalidID();
//@}
//**********************************************************************************************
static inline id_t count() { return counter_; }
static inline id_t globalCount() { return globalCounter_; }
private:
//**Member variables****************************************************************************
/*!\name Member variables */
//@{
static id_t counter_; //!< System ID counter.
static id_t globalCounter_; //!< Global system ID counter.
//@}
//**********************************************************************************************
};
//*************************************************************************************************
//=================================================================================================
//
// DEFINITION AND INITIALIZATION OF THE STATIC MEMBER VARIABLES
//
//=================================================================================================
template< typename T >
id_t UniqueID<T>::counter_( 1 );
template< typename T >
id_t UniqueID<T>::globalCounter_( 1 );
//=================================================================================================
//
// UTILITY FUNCTIONS
//
//=================================================================================================
//*************************************************************************************************
/*!\brief Generates a unique ID.
*
* \return The newly generated unique ID.
*/
template< typename T >
inline id_t UniqueID<T>::create()
{
id_t id( counter_++ );
if( MPIManager::instance()->bitsNeededToRepresentRank() > 0 ) {
const size_t shift( sizeof(id_t)*size_t(8) - MPIManager::instance()->bitsNeededToRepresentRank() );
WALBERLA_ASSERT( shift < sizeof(id_t)*size_t(8), "Invalid shift detected" );
const int rank ( MPIManager::instance()->worldRank() );
WALBERLA_ASSERT( rank >= 0, "MPI system is not initialized" );
if( counter_ >= ( id_t(1) << shift ) ) {
// Revert overflow of counter
--counter_;
throw std::runtime_error( "Unable to create unique ID" );
}
id |= ( static_cast<id_t>( rank ) << shift );
}
else if( counter_ == size_t(0) ) {
// Revert overflow of counter
--counter_;
throw std::runtime_error( "Unable to create unique ID" );
}
return id;
}
//*************************************************************************************************
//*************************************************************************************************
/*!\brief Generates an ID which is the same on all processes but unique on each process.
*
* \return The newly generated ID.
*/
template< typename T >
inline id_t UniqueID<T>::createGlobal()
{
id_t id( globalCounter_++ );
if( MPIManager::instance()->bitsNeededToRepresentRank() > 0 ) {
const size_t shift( sizeof(id_t)*size_t(8) - MPIManager::instance()->bitsNeededToRepresentRank() );
WALBERLA_ASSERT( shift < sizeof(id_t)*size_t(8), "Invalid shift detected" );
const int size( MPIManager::instance()->numProcesses() );
WALBERLA_ASSERT( size >= 0, "MPI system is not initialized" );
if( globalCounter_ >= ( id_t(1) << shift ) ) {
// Revert overflow of counter
--globalCounter_;
throw std::runtime_error( "Unable to create unique ID" );
}
id |= ( static_cast<id_t>( size ) << shift );
}
else if( globalCounter_ == size_t(0) ) {
// Revert overflow of counter
--globalCounter_;
throw std::runtime_error( "Unable to create unique ID" );
}
return id;
}
//*************************************************************************************************
//*************************************************************************************************
/*!\brief Returns an invalid ID
*
* \return invalid ID.
*/
template< typename T >
inline id_t UniqueID<T>::invalidID()
{
return 0;
}
//*************************************************************************************************
}