ana::HistCache Class Reference

Helper for Spectrum. More...

#include <HistCache.h>

Static Public Member Functions
static TH1D *	New (const std::string &title, const Binning &bins)
static TH1D *	New (const std::string &title, const TAxis *bins)
static TH1D *	Copy (const TH1D *h)
static TH2D *	NewTH2D (const std::string &title, const Binning &xbins, const Binning &ybins)
static TH2D *	NewTH2D (const std::string &title, const TAxis *xbins, const TAxis *ybins)
static TH2D *	Copy (const TH2D *h)
static void	Delete (TH1D *&h)
static void	Delete (TH2D *&h)
static void	PrintStats ()
static void	ClearCache ()

Static Protected Member Functions
static void	CheckMemoryUse ()

Static Protected Attributes
static std::multimap< int, std::unique_ptr< TH1D > >	fgMap
static std::multimap < std::pair< int, int > , std::unique_ptr< TH2D > >	fgMap2D
static int	fgOut = 0
static int	fgIn = 0
static long	fgEstMemUsage = 0
static long	fgMemHandedOut = 0

Detailed Description

Helper for Spectrum.

ROOT's handling of allocations, and especially deletions, can be very slow. It keeps everything in a big map that it then has to lookups in. This class provides a simple cache of histograms, recycling an old histogram of the same binning instead of creating a new one.

Allocate new histograms with New, and return them to the cache with Delete.

Definition at line 24 of file HistCache.h.

Member Function Documentation

void ana::HistCache::CheckMemoryUse ( )

staticprotected

Definition at line 126 of file HistCache.cxx.

  {
    if(fgEstMemUsage > 500l*1024*1024){
      std::cerr << "Warning! HistCache memory usage exceeds 500MB. "
                << "That probably means histograms are being returned "
                << "to the cache that weren't originally handed out by it. "
                << std::endl;
      PrintStats();
      std::cerr << "Now clearing cache. This could take a long time..."
                << std::endl;
      ClearCache();
      std::cerr << "Done clearing cache" << std::endl;
    }
  }

void ana::HistCache::ClearCache ( )

static

Definition at line 142 of file HistCache.cxx.

  {
    fgMap.clear();
    fgMap2D.clear();
    fgEstMemUsage = 0;
    fgOut = 0;
    fgIn = 0;
  }

TH1D * ana::HistCache::Copy ( const TH1D *  h )

static

Definition at line 76 of file HistCache.cxx.

  {
    TH1D* ret = New(h->GetTitle(), h->GetXaxis());
    *ret = *h;
    return ret;
  }

TH2D * ana::HistCache::Copy ( const TH2D *  h )

static

Definition at line 84 of file HistCache.cxx.

  {
    TH2D* ret = NewTH2D(h->GetTitle(), h->GetXaxis(), h->GetYaxis());
    *ret = *h;
    return ret;
  }

void ana::HistCache::Delete ( TH1D *&  h )

static

Definition at line 92 of file HistCache.cxx.

  {
    if(!h) return;

    ++fgIn;
    fgMemHandedOut -= 16*h->GetNbinsX();

    fgMap.emplace(Binning::FromTAxis(h->GetXaxis()).ID(),
                  std::unique_ptr<TH1D>(h));

    fgEstMemUsage += 16*h->GetNbinsX();
    CheckMemoryUse();

    h = 0;
  }

void ana::HistCache::Delete ( TH2D *&  h )

static

Definition at line 109 of file HistCache.cxx.

  {
    if(!h) return;

    ++fgIn;
    fgMemHandedOut -= 16*h->GetNbinsX()*h->GetNbinsY();

    fgMap2D.emplace(std::pair<int, int>(Binning::FromTAxis(h->GetXaxis()).ID(), Binning::FromTAxis(h->GetYaxis()).ID()), 
                    std::unique_ptr<TH2D>(h));

    fgEstMemUsage += 16*h->GetNbinsX()*h->GetNbinsY();
    CheckMemoryUse();

    h = 0;
  }

TH1D * ana::HistCache::New ( const std::string &  title, const Binning &  bins  )

static

Definition at line 21 of file HistCache.cxx.

  {
    ++fgOut;
    fgMemHandedOut += 16*bins.NBins();

    // Look in the cache
    auto it = fgMap.find(bins.ID());
    if(it != fgMap.end()){
      TH1D* ret = it->second.release();
      fgMap.erase(it);
      ret->Reset();
      ret->SetTitle(title.c_str());

      fgEstMemUsage -= 16*bins.NBins();

      return ret;
    }

    // If not, create a new one directly
    return MakeTH1D(UniqueName().c_str(), title.c_str(), bins);
  }

TH1D * ana::HistCache::New ( const std::string &  title, const TAxis *  bins  )

static

Definition at line 44 of file HistCache.cxx.

  {
    return New(title, Binning::FromTAxis(bins));
  }

TH2D * ana::HistCache::NewTH2D ( const std::string &  title, const Binning &  xbins, const Binning &  ybins  )

static

Definition at line 50 of file HistCache.cxx.

  {
    ++fgOut;
    fgMemHandedOut += 16*xbins.NBins()*ybins.NBins();

    std::pair<int, int> IDs (xbins.ID(), ybins.ID());
    auto it = fgMap2D.find(IDs);
    if(it != fgMap2D.end()){
      TH2D* ret = it->second.release();
      fgMap2D.erase(it);
      ret->Reset();
      ret->SetTitle(title.c_str());
      fgEstMemUsage -= 16*xbins.NBins()*ybins.NBins();
      return ret;
    }

    return MakeTH2D(UniqueName().c_str(), title.c_str(), xbins, ybins);
  }

TH2D * ana::HistCache::NewTH2D ( const std::string &  title, const TAxis *  xbins, const TAxis *  ybins  )

static

Definition at line 70 of file HistCache.cxx.

  {
    return NewTH2D(title, Binning::FromTAxis(xbins), Binning::FromTAxis(ybins));
  }

void ana::HistCache::PrintStats ( )

static

Definition at line 152 of file HistCache.cxx.

  {
    // Count number of unique keys
    std::set<int> keys;
    for(auto& it: fgMap) keys.insert(it.first);

    std::cout << "Gave out " << fgOut << " histograms, got back "
              << fgIn << " of them (" << fgOut-fgIn << " still out, totalling "
              << fgMemHandedOut << " bytes), in "
              << keys.size() << " different shapes." << std::endl
              << "Holding " << fgMap.size()+fgMap2D.size()
              << " histograms for an estimated memory usage of "
              << fgEstMemUsage << " bytes." << std::endl;
  }

Member Data Documentation

long ana::HistCache::fgEstMemUsage = 0

staticprotected

Definition at line 48 of file HistCache.h.

int ana::HistCache::fgIn = 0

staticprotected

Definition at line 46 of file HistCache.h.

std::multimap< int, std::unique_ptr< TH1D > > ana::HistCache::fgMap

staticprotected

Definition at line 43 of file HistCache.h.

std::multimap< std::pair< int, int >, std::unique_ptr< TH2D > > ana::HistCache::fgMap2D

staticprotected

Definition at line 44 of file HistCache.h.

long ana::HistCache::fgMemHandedOut = 0

staticprotected

Definition at line 49 of file HistCache.h.

int ana::HistCache::fgOut = 0

staticprotected

Definition at line 46 of file HistCache.h.

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The documentation for this class was generated from the following files:

• HistCache.h
• HistCache.cxx