Optimizing CUDA parallel reduction.

/***************************************************************************

                          tnlCudaReductionBuffer.h  -  description

                             -------------------

    begin                : June 17, 2015

    copyright            : (C) 2015 by Tomas Oberhuber

    email                : tomas.oberhuber@fjfi.cvut.cz

 ***************************************************************************/

/***************************************************************************

 *                                                                         *

 *   This program 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 2 of the License, or     *

 *   (at your option) any later version.                                   *

 *                                                                         *

 ***************************************************************************/

#ifndef TNLCUDAREDUCTIONBUFFER_H

#define	TNLCUDAREDUCTIONBUFFER_H

#include <core/tnlCuda.h>

class tnlCudaReductionBuffer

{

   public:

      inline tnlCudaReductionBuffer( size_t size = 0 ): data( 0 ), size( 0 )

      {

         if( size != 0 ) setSize( size );

      }

      inline bool setSize( size_t size )

      {

#ifdef HAVE_CUDA         

         if( size > this->size )

         {

            this->size = size;

            if( cudaMalloc( ( void** ) &this->data, size ) != cudaSuccess )

            {

               cerr << "I am not able to allocate reduction buffer on the GPU." << endl;

               this->data = 0;

            }

            return checkCudaDevice;

         }

         else

            return true;

#else

         return false;

#endif         

      }

      template< typename Type >

      Type* getData() { return ( Type* ) this->data; }

      inline ~tnlCudaReductionBuffer()

      {

#ifdef HAVE_CUDA         

         if( data ) cudaFree( data );

#endif         

      }

   protected:

      void* data;

      size_t size;

};

#endif	/* TNLCUDAREDUCTIONBUFFER_H */