RooPullVar.cxx

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/*****************************************************************************
 * Project: RooFit                                                           *
 * Package: RooFitCore                                                       *
 * @(#)root/roofitcore:$Id$
 * 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)             *
 *****************************************************************************/
 
/**
\file RooPullVar.cxx
\class RooPullVar
\ingroup Roofitcore
 
Class RooPullVar represents the pull of measurement w.r.t to true value
using the measurement value and its error. Both the true value and
the measured value (with error) are taken from two user supplied
RooRealVars. If an asymmetric error is defined on a given measurement the proper 
side of that asymmetric error will be used
**/
 
#include "RooFit.h"
 
#include "Riostream.h"
#include "Riostream.h"
#include <math.h>
 
#include "RooPullVar.h"
#include "RooAbsReal.h"
#include "RooRealVar.h"
 
using namespace std;
 
ClassImp(RooPullVar);
;
 
 
////////////////////////////////////////////////////////////////////////////////
/// Default constructor
 
RooPullVar::RooPullVar()
{
}
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Construct RooAbsReal representing the pull of a RooRealVar 'meas' providing the
/// measured value and its error and a RooAbsReal 'truth' providing the true value
 
RooPullVar::RooPullVar(const char* name, const char* title, RooRealVar& meas, RooAbsReal& truth) :
  RooAbsReal(name, title),
  _meas("meas","Measurement",this,meas),
  _true("true","Truth",this,truth)
{
}
 
 
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Copy constructor
 
RooPullVar::RooPullVar(const RooPullVar& other, const char* name) :
  RooAbsReal(other, name), 
  _meas("meas",this,other._meas),
  _true("true",this,other._true)
{
}
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Destructor
 
RooPullVar::~RooPullVar() 
{
}
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Calculate pull. Use asymmetric error if defined in measurement,
/// otherwise use symmetric error. If measurement has no error
/// return zero.
 
Double_t RooPullVar::evaluate() const 
{
  const RooRealVar& meas = static_cast<const RooRealVar&>(_meas.arg()) ;  
  if (meas.hasAsymError()) {
    Double_t delta = _meas-_true ;
    if (delta<0) {
      return delta/meas.getAsymErrorHi() ;
    } else {
      return -delta/meas.getAsymErrorLo() ;
    }
  } else if (meas.hasError()) {
    return (_meas-_true)/meas.getError() ;    
  } else {
    return 0 ;
  }
}