FairDivide.h File Reference

A collection of functions for dividing fairly. More...

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Functions
template<typename IType >
std::tuple< IType, IType >	FairDivideBoundary (IType me, IType ntot, IType npart)
	Partition ntot over npart. More...
template<class IV >
void	FairDivide (int ntot, int npart, IV &adist)
	Partition ntot over npart. More...
template<class IV >
std::vector< IV >	fairDivide (IV ntot, IV npart)
	return the occupation vector for ntot entities partitioned npart ways. More...
void	FairDivideAligned (const int ntot, const int base, const int npart, const int me, int &first, int &last)
	Partition ntot over npart and the size of each partition is a multiple of base size. More...
template<class IV >
void	FairDivideLow (int ntot, int npart, IV &adist)
	partition ntot elements among npart More...
template<class IV >
int	FairDivideHigh (int me, int ntot, int npart, IV &adist)
	partition ntot elements among npart More...
template<class IV >
int	FairDivideLow (int me, int ntot, int npart, IV &adist)
	partition ntot elements among npart More...

Detailed Description

A collection of functions for dividing fairly.

Definition in file FairDivide.h.

Function Documentation

FairDivide()

void FairDivide ( int  ntot, int  npart, IV &  adist  )

inline

Partition ntot over npart.

Parameters

ntot	the total size
npart	the number of partitions
adist	an index array

Simply divide ntot data among npart partitions so that the size of each group cannot differ by more than 1.

The array adist contains the offset for the i-th group, i.e., adist[i+1]-adist[i] is the number of elements for the i-th group.

Definition at line 57 of file FairDivide.h.

Referenced by QMCCostFunctionBatched::checkConfigurations(), QMCCostFunctionBatched::correlatedSampling(), and QMCCostFunctionBatched::fillOverlapHamiltonianMatrices().

{
  if (adist.size() != npart + 1)
    adist.resize(npart + 1);
  int bat     = ntot / npart;
  int residue = ntot % npart;
  adist[0]    = 0;
  for (int i = 1; i < npart; i++)
  {
    if (i < residue)
      adist[i] = adist[i - 1] + bat + 1;
    else
      adist[i] = adist[i - 1] + bat;
  }
  adist[npart] = ntot;
}

fairDivide()

std::vector<IV> fairDivide	(	IV	ntot,
		IV	npart
	)

return the occupation vector for ntot entities partitioned npart ways.

Definition at line 77 of file FairDivide.h.

References OMPstd::fill_n().

Referenced by QMCDriverNew::adjustGlobalWalkerCount(), MCPopulation::redistributeWalkers(), and qmcplusplus::TEST_CASE().

{
  IV bat = ntot / npart;
  IV residue = ntot % npart;
  std::vector<IV> partitions(npart, 0);
  std::fill_n(partitions.begin(), residue, bat + 1);
  std::fill_n(partitions.begin() + residue, npart - residue, bat);
  return partitions;
}

FairDivideAligned()

void FairDivideAligned ( const int  ntot, const int  base, const int  npart, const int  me, int &  first, int &  last  )

inline

Partition ntot over npart and the size of each partition is a multiple of base size.

Parameters

ntot	the total size
base	the base size
npart	the number of partitions
me	my partition id [0,ntot)
first	the beginning of my partition, can be equal and larger than ntot
last	the end of my partition, must be smaller than ntot

Definition at line 96 of file FairDivide.h.

References qmcplusplus::Units::mass::me, and omptarget::min().

Referenced by SoaDistanceTableAB< T, D, SC >::evaluate(), SplineC2R< ST >::evaluateDetRatios(), SplineC2C< ST >::evaluateDetRatios(), SplineR2R< ST >::evaluateDetRatios(), SplineC2R< ST >::evaluateValue(), SplineC2C< ST >::evaluateValue(), SplineR2R< ST >::evaluateValue(), SplineC2COMPTarget< ST >::evaluateValue(), SplineC2ROMPTarget< ST >::evaluateValue(), SplineC2R< ST >::evaluateVGH(), SplineR2R< ST >::evaluateVGH(), SplineC2C< ST >::evaluateVGH(), SplineC2COMPTarget< ST >::evaluateVGH(), SplineC2ROMPTarget< ST >::evaluateVGH(), SplineC2R< ST >::evaluateVGHGH(), SplineR2R< ST >::evaluateVGHGH(), SplineC2C< ST >::evaluateVGHGH(), SplineC2COMPTarget< ST >::evaluateVGHGH(), SplineC2ROMPTarget< ST >::evaluateVGHGH(), SplineC2R< ST >::evaluateVGL(), SplineR2R< ST >::evaluateVGL(), SplineC2C< ST >::evaluateVGL(), and qmcplusplus::TEST_CASE().

{
  const int blocksize = (((ntot + npart - 1) / npart + base - 1) / base) * base;
  first               = me * blocksize;
  last                = std::min((me + 1) * blocksize, ntot);
  if (first > last)
    first = last;
}

FairDivideBoundary()

std::tuple<IType, IType> FairDivideBoundary ( IType  me, IType  ntot, IType  npart  )

inline

Partition ntot over npart.

Parameters

me	index of boundaries being returned
ntot	the total size
npart	the number of partitions

Simply divide ntot data among npart partitions so that the size of each group cannot differ by more than 1. Return the boundaries of the partition associated with partition 'me'

Definition at line 35 of file FairDivide.h.

References qmcplusplus::Units::mass::me.

{
  IType bat     = ntot / npart;
  IType residue = ntot % npart;
  if (me < residue)
    return std::make_tuple(me * (bat + 1), (me + 1) * (bat + 1));
  else
    return std::make_tuple(me * bat + residue, (me + 1) * bat + residue);
}

FairDivideHigh()

int FairDivideHigh ( int  me, int  ntot, int  npart, IV &  adist  )

inline

partition ntot elements among npart

Parameters

me	rank [0,ntot)
ntot	total number of elements
npart	number of partitions
adist	distribution offset

Returns

partition id to which me belongs

mypart satisfies adist[mypart] <= me < adist[mypart+1]

Definition at line 140 of file FairDivide.h.

References qmcplusplus::Units::mass::me.

{
  if (adist.size() != npart + 1)
    adist.resize(npart + 1);
  int bat     = ntot / npart;
  int residue = ntot % npart;
  int mypart  = 0;
  adist[0]    = 0;
  for (int i = 1; i < npart; i++)
  {
    if (i < residue)
      adist[i] = adist[i - 1] + bat + 1;
    else
      adist[i] = adist[i - 1] + bat;
    if (me >= adist[i] && me < adist[i + 1])
      mypart = i;
  }
  adist[npart] = ntot;
  return mypart;
}

FairDivideLow() [1/2]

void FairDivideLow ( int  ntot, int  npart, IV &  adist  )

inline

partition ntot elements among npart

Parameters

ntot	total number of elements
npart	number of partitions
adist	distribution offset

adist[ip-1]-adist[ip] is the number of elements of ip partition This method makes the zero-th node equal to or less than 1.

Definition at line 114 of file FairDivide.h.

Referenced by HybridRepSetReader< SA >::create_atomic_centers_Gspace(), WalkerControlMPI::determineNewWalkerPopulation(), WalkerControl::determineNewWalkerPopulation(), SplineC2R< ST >::gather_tables(), SplineR2R< ST >::gather_tables(), SplineC2C< ST >::gather_tables(), SplineC2COMPTarget< ST >::gather_tables(), SplineC2ROMPTarget< ST >::gather_tables(), qmcplusplus::generateCuspInfo(), HybridRepSetReader< SA >::initialize_hybrid_pio_gather(), SplineSetReader< typename SA::SplineBase >::initialize_spline_pio_gather(), HDFWalkerInput_0_4::read_hdf5(), HDFWalkerInput_0_4::read_hdf5_scatter(), HDFWalkerInput_0_4::read_phdf5(), RMC::resetReptiles(), VMC::resetRun(), CSVMC::resetRun(), DMC::resetUpdateEngines(), DMC::run(), and qmcplusplus::TEST_CASE().

{
  if (adist.size() != npart + 1)
    adist.resize(npart + 1);
  int bat     = ntot / npart;
  int residue = npart - ntot % npart;
  adist[0]    = 0;
  for (int i = 0; i < npart; i++)
  {
    if (i < residue)
      adist[i + 1] = adist[i] + bat;
    else
      adist[i + 1] = adist[i] + bat + 1;
  }
}

FairDivideLow() [2/2]

int FairDivideLow ( int  me, int  ntot, int  npart, IV &  adist  )

inline

partition ntot elements among npart

Parameters

me	rank [0,ntot)
ntot	total number of elements
npart	number of partitions
adist	distribution offset

Returns

partition id to which me belongs

mypart satisfies adist[mypart] <= me < adist[mypart+1]

Definition at line 171 of file FairDivide.h.

References qmcplusplus::Units::mass::me.

{
  if (adist.size() != npart + 1)
    adist.resize(npart + 1);
  int bat     = ntot / npart;
  int residue = npart - ntot % npart;
  int mypart  = 0;
  adist[0]    = 0;
  for (int i = 0; i < npart; i++)
  {
    if (i < residue)
      adist[i + 1] = adist[i] + bat;
    else
      adist[i + 1] = adist[i] + bat + 1;
    if (me >= adist[i] && me < adist[i + 1])
      mypart = i;
  }
  return mypart;
}