RooAbsSelfCachedReal.cxx

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  * Project: RooFit                                                           * 
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/**
\file RooAbsSelfCachedReal.cxx
\class RooAbsSelfCachedReal
\ingroup Roofitcore

RooAbsSelfCachedReal is an abstract base class for functions whose
output is cached in terms of a histogram in all observables between
getVal() and evaluate(). For certain p.d.f.s that are very
expensive to calculate it may be beneficial to implement them as a
RooAbsSelfCachedReal rather than a RooAbsReal. Class
RooAbsSelfCachedReal is designed to have its interface identical to
that of RooAbsReal, so any p.d.f can make use of its caching
functionality by merely switching its base class.  Existing
RooAbsReal objects can also be cached a posteriori with the
RooCachedReal wrapper function that takes any RooAbsReal object as
input.
**/

#include "Riostream.h" 

#include "RooFit.h"
#include "RooAbsSelfCachedReal.h" 
#include "RooAbsReal.h" 
#include "RooMsgService.h"
#include "RooDataHist.h"
#include "RooHistPdf.h"

using namespace std ;

ClassImp(RooAbsSelfCachedReal); 



////////////////////////////////////////////////////////////////////////////////
/// Constructor

RooAbsSelfCachedReal::RooAbsSelfCachedReal(const char *name, const char *title, Int_t ipOrder) :
  RooAbsCachedReal(name,title,ipOrder)
 { 
 } 



////////////////////////////////////////////////////////////////////////////////
/// Copy constructor

RooAbsSelfCachedReal::RooAbsSelfCachedReal(const RooAbsSelfCachedReal& other, const char* name) :  
   RooAbsCachedReal(other,name)
 { 
 } 



////////////////////////////////////////////////////////////////////////////////
/// Destructor

RooAbsSelfCachedReal::~RooAbsSelfCachedReal() 
{
}



////////////////////////////////////////////////////////////////////////////////
/// Fill cache with sampling of function as defined by the evaluate() implementation

void RooAbsSelfCachedReal::fillCacheObject(RooAbsCachedReal::FuncCacheElem& cache) const 
{
  RooDataHist& cacheHist = *cache.hist() ;

  // Make deep clone of self in non-caching mde and attach to dataset observables
  RooArgSet* cloneSet = (RooArgSet*) RooArgSet(*this).snapshot(kTRUE) ;
  RooAbsSelfCachedReal* clone2 = (RooAbsSelfCachedReal*) cloneSet->find(GetName()) ;
  clone2->disableCache(kTRUE) ;
  clone2->attachDataSet(cacheHist) ;

  // Iterator over all bins of RooDataHist and fill weights
  for (Int_t i=0 ; i<cacheHist.numEntries() ; i++) {
    const RooArgSet* obs = cacheHist.get(i) ;
    Double_t wgt = clone2->getVal(obs) ;
    cacheHist.set(wgt) ;
  }

  delete cloneSet ;
}



////////////////////////////////////////////////////////////////////////////////
/// Defines observables to be cached, given a set of user defined observables
/// Returns the subset of nset that are observables this p.d.f

RooArgSet* RooAbsSelfCachedReal::actualObservables(const RooArgSet& nset) const 
{
  // Make list of servers
  RooArgSet serverSet;

  for (auto server : _serverList) {
    serverSet.add(*server);
  }
  
  // Return servers that are in common with given normalization set
  return (RooArgSet*) serverSet.selectCommon(nset);
  
}


////////////////////////////////////////////////////////////////////////////////
/// Defines parameters on which cache contents depends. Returns
/// subset of variables of self that is not contained in the
/// supplied nset

RooArgSet* RooAbsSelfCachedReal::actualParameters(const RooArgSet& nset) const 
{  
  // Make list of servers
  RooArgSet *serverSet = new RooArgSet;
  
  for (auto server : _serverList) {
    serverSet->add(*server);
  }
  
  // Remove all given observables from server list
  serverSet->remove(nset,kTRUE,kTRUE);

  return serverSet;
}