/*****************************************************************************
 * Project: RooFit                                                           *
 * Package: RooFitCore                                                       *
 * @(#)root/roofitcore:$Name:  $:$Id: RooEfficiency.cxx,v 1.10 2007/05/14 14:37:31 wouter Exp $
 * Authors:                                                                  *
 *   WV, Wouter Verkerke, UC Santa Barbara, verkerke@slac.stanford.edu       *
 *   DK, David Kirkby,    UC Irvine,         dkirkby@uci.edu                 *
 *                                                                           *
 * Copyright (c) 2000-2005, Regents of the University of California          *
 *                          and Stanford University. All rights reserved.    *
 *                                                                           *
 * Redistribution and use in source and binary forms,                        *
 * with or without modification, are permitted according to the terms        *
 * listed in LICENSE (http://roofit.sourceforge.net/license.txt)             *
 *****************************************************************************/

// -- CLASS DESCRIPTION [PDF] --
// RooEfficiency is a PDF helper class to fit efficiencies parameterized
// by a supplied function F.
// 
// Given a dataset with a category C that determines if a given
// event is accepted or rejected for the efficiency to be measured,
// this class evaluates as F if C is 'accept' and as (1-F) if
// C is 'reject'. Values of F below 0 and above 1 are clipped.
// F may have an arbitrary number of dependents and parameters

#include "RooFit.h"

#include "RooEfficiency.h"
#include "RooEfficiency.h"
#include "RooStreamParser.h"
#include "RooArgList.h"

ClassImp(RooEfficiency)
  ;

RooEfficiency::RooEfficiency(const char *name, const char *title, const RooAbsReal& effFunc, const RooAbsCategory& cat, const char* sigCatName) :
  RooAbsPdf(name,title),
  _cat("cat","Signal/Background category",this,(RooAbsCategory&)cat),
  _effFunc("effFunc","Efficiency modeling function",this,(RooAbsReal&)effFunc),
  _sigCatName(sigCatName)
{  
  // Constructor with title used as formula expression
}


RooEfficiency::RooEfficiency(const RooEfficiency& other, const char* name) : 
  RooAbsPdf(other, name),
  _cat("cat",this,other._cat),
  _effFunc("effFunc",this,other._effFunc),
  _sigCatName(other._sigCatName)
{
  // Copy constructor
}


RooEfficiency::~RooEfficiency() 
{
  // Destructor
}


Double_t RooEfficiency::evaluate() const
{
  // Calculate current value of this object
  Double_t effFuncVal = _effFunc ;

  // Truncate efficiency function in range 0.0-1.0
  if (_effFunc>1) {
    effFuncVal = 1.0 ;
  } else if (_effFunc<0) {
    effFuncVal = 0.0 ;
  }

  if (_cat == _sigCatName) {
    // Accept case
    return effFuncVal ;
  } else {
    // Reject case
    return 1 - effFuncVal ;
  }
}