mult_common_th-inc.h

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#ifndef MULT_COMMON_TH_INCLUDED
#define MULT_COMMON_TH_INCLUDED
 
#ifdef USE_BENCHMARK
#include <omp.h>
#endif
 
namespace {
//====================================================================
// case (a): tasks are equally assgined to all threads
 
/*
inline void set_threadtask_mult(int& ith, int& nth, int& is, int& ns,
                           const int size)
{
  nth = ThreadManager::get_num_threads();
  ith = ThreadManager::get_thread_id();
 
  is = size * ith / nth;
  ns = size * (ith + 1) / nth;
 
}
*/
//====================================================================
// case (b): tasks are almost assigned to slave threads.
 
/*
inline void set_threadtask_mult(int& ith, int& nth, int& is, int& ns,
                           const int size)
{
  nth = ThreadManager::get_num_threads();
  ith = ThreadManager::get_thread_id();
 
  if(nth > 1){
    int offset = size % (nth-1);
    int ntask = size/(nth-1);
    is = offset + ntask * (ith-1);
    if(ith == 0) is = 0;
    ns = offset + ntask * ith;
  }else{
    is = 0;
    ns = size;
  }
 
}
*/
//====================================================================
// case (c): tasks are assigned only to slave threads.
 
  inline void set_threadtask_mult(int& ith, int& nth, int& is, int& ns,
                                  const int size)
  {
#ifdef USE_BENCHMARK
    nth = omp_get_num_threads();
    ith = omp_get_thread_num();
#else
    nth = ThreadManager::get_num_threads();
    ith = ThreadManager::get_thread_id();
#endif
 
    if (nth == 1) {
      is = 0;
      ns = size;
    } else {
      is = size * (ith - 1) / (nth - 1);
      if (ith == 0) is = 0;
      ns = size * ith / (nth - 1);
    }
  }
 
 
//====================================================================
} // nameless namespace end
 
#endif
//============================================================END=====