RooPoisson.h

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 /*****************************************************************************
  * Project: RooFit                                                           *
  *                                                                           *
  * Simple Poisson PDF
  * author: Kyle Cranmer <cranmer@cern.ch>
  *                                                                           *
  *****************************************************************************/
 
#ifndef ROOPOISSON
#define ROOPOISSON
 
#include "RooAbsPdf.h"
#include "RooRealProxy.h"
#include "RooCategoryProxy.h"
#include "RooAbsReal.h"
#include "RooAbsCategory.h"
#include "RooTrace.h"
 
class RooPoisson : public RooAbsPdf {
public:
  RooPoisson() { _noRounding = false ;   } ;
  // Original constructor without RooAbsReal::Ref for backwards compatibility.
  inline RooPoisson(const char *name, const char *title, RooAbsReal& _x, RooAbsReal& _mean, bool noRounding=false)
      : RooPoisson{name, title, RooAbsReal::Ref{_x}, RooAbsReal::Ref{_mean}, noRounding} {}
  RooPoisson(const char *name, const char *title, RooAbsReal::Ref _x, RooAbsReal::Ref _mean, bool noRounding=false);
  RooPoisson(const RooPoisson& other, const char* name=nullptr) ;
  TObject* clone(const char* newname) const override { return new RooPoisson(*this,newname); }
 
  Int_t getAnalyticalIntegral(RooArgSet& allVars, RooArgSet& analVars, const char* rangeName=nullptr) const override;
  double analyticalIntegral(Int_t code, const char* rangeName=nullptr) const override;
 
  Int_t getGenerator(const RooArgSet& directVars, RooArgSet &generateVars, bool staticInitOK=true) const override;
  void generateEvent(Int_t code) override;
 
  /// Switch off/on rounding of `x` to the nearest integer.
  void setNoRounding(bool flag = true) {_noRounding = flag;}
  bool getNoRounding() const { return _noRounding; }
  
  /// Switch on or off protection against negative means.
  void protectNegativeMean(bool flag = true) {_protectNegative = flag;}
 
  /// Get the x variable.
  RooAbsReal const& getX() const { return x.arg(); }
 
  /// Get the mean parameter.
  RooAbsReal const& getMean() const { return mean.arg(); }
 
  void translate(RooFit::Detail::CodeSquashContext &ctx) const override;
  std::string
  buildCallToAnalyticIntegral(int code, const char *rangeName, RooFit::Detail::CodeSquashContext &ctx) const override;
 
protected:
 
  RooRealProxy x ;
  RooRealProxy mean ;
  bool  _noRounding ;
  bool  _protectNegative{true};
 
  double evaluate() const override;
  void computeBatch(double* output, size_t nEvents, RooFit::Detail::DataMap const&) const override;
  inline bool canComputeBatchWithCuda() const override { return true; }
 
  ClassDefOverride(RooPoisson,3) // A Poisson PDF
};
 
#endif