include/oned/nicol_plus_interval_impl.hpp

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// This file is part of SPart, Spatially Located Workload Partitioner.

// Copyright (C) 2011, The Ohio State University
// SPart developed by Erdeniz O. Bas, Erik Saule and Umit V. Catalyurek 

// For questions, comments, suggestions, bugs please send e-mail to: 
// Umit V. Catalyurek   catalyurek.1@osu.edu

// SPart 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 or (at your option) any later
// version.

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// for more details.

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// As a special exception, if other files instantiate templates or use
// macros or inline functions from this file, or you compile this file
// and link it with other works to produce a work based on this file,
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#include <oned/nicol_plus_interval.hpp>


template <typename T, typename Pr>
T oned::Nicol_plus_interval<T,Pr>::nicol_plus_internal(const Pr& wpre, int length,
                                                       int numproc, T , int *sl, int *sh)
{
  using namespace util;
  int ilast = 1, b;
  int ilow, ihigh, imid;
  T bottleneck, Bopt;

  T lb = 0; // there is no good lower bound if the intervals does not respect load(I_a \union I_b) = load(I_a)+load(I_b)
  T ub = wpre.interval(0,length - 1);
  int *s = new int[numproc];
  int *oris = s;
  Bopt = ub;

  for(b=0; b < numproc - 1; b++)
    {

      ilow = (sl[b]<ilast?ilast-1:sl[b]);
      ihigh=length-1;
      assert (ilow <= ihigh);

      while(ilow < ihigh)
        {
          imid = (ilow + ihigh) / 2;
          bottleneck = wpre.interval(ilast - 1,imid);
          assert (bottleneck >=0);
          if((lb <= bottleneck) && (bottleneck < ub))
            {
              if(ParametricSearch<T,Pr>::rprobe_interval(wpre, length, bottleneck, numproc, s, sl, sh))
                {
                  int *tmp;
                  tmp=s;
                  s=sh;
                  sh=tmp;
                  ub = bottleneck;
                  ihigh = imid;
                }
              else
                {
                  int *tmp;
                  tmp=s;
                  s=sl;
                  sl=tmp;
                  lb = bottleneck;
                  ilow = imid + 1;
                }
            }
          else if(bottleneck >= ub)
            {
              ihigh = imid;
            }
          else
            {
              ilow = imid + 1;
            }
        }
      assert (ilow == ihigh);
      assert(b < numproc);

      Bopt = std::min(Bopt, wpre.interval(ilast - 1, ihigh)); //if b is the bottleneck, it executes [ilast-1:high]
      ilast = ihigh;
    }

  Bopt = std::min(Bopt, wpre.interval(ilast-1,length-1));
  delete[] oris;
  return Bopt;
}


template <typename T, typename Pr>
T oned::Nicol_plus_interval<T,Pr>::nicol_plus(int procCount, const Pr& prefixSumArray,
                                              int length, int *cutIndexes, T max)
{
  using namespace util;
  int i;
  int *sl =  new int[procCount];
  int *sh =  new int[procCount];
  T b;

  for(i = 0; i < procCount; i++)
    {
      sl[i] = 1;
      sh[i] = length - 1;
    }

  b = nicol_plus_internal (prefixSumArray, length, procCount, max, sl, sh);

  if (cutIndexes != NULL)
    {
#ifndef NDEBUG
      int valid = ParametricSearch<T,Pr>::probeCut_interval(b, procCount - 1, prefixSumArray, length, cutIndexes);
      assert(valid==1);
#endif
#ifdef NDEBUG
      ParametricSearch<T,Pr>::probeCut_interval(b, procCount - 1, prefixSumArray, length, cutIndexes);
#endif
    }
  else
    {
      std::cerr << "Error: cutIndexes not allocated in nicol plus 2d!" << std::endl;
    }

  delete[] sl;
  delete[] sh;
  return b;
}