//////////////////////////////////////////////////////////////////////////
//
// 'MULTIDIMENSIONAL MODELS' RooFit tutorial macro #306
// 
// Complete example with use of conditional p.d.f. with per-event errors
//
//
//
// 07/2008 - Wouter Verkerke 
// 
/////////////////////////////////////////////////////////////////////////

#ifndef __CINT__
#include "RooGlobalFunc.h"
#endif
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooConstVar.h"
#include "RooGaussModel.h"
#include "RooDecay.h"
#include "RooLandau.h"
#include "RooPlot.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TH2D.h"
using namespace RooFit ;



void rf306_condpereventerrors()
{
  // B - p h y s i c s   p d f   w i t h   p e r - e v e n t  G a u s s i a n   r e s o l u t i o n
  // ----------------------------------------------------------------------------------------------

  // Observables
  RooRealVar dt("dt","dt",-10,10) ;
  RooRealVar dterr("dterr","per-event error on dt",0.01,10) ;

  // Build a gaussian resolution model scaled by the per-event error = gauss(dt,bias,sigma*dterr)
  RooRealVar bias("bias","bias",0,-10,10) ;
  RooRealVar sigma("sigma","per-event error scale factor",1,0.1,10) ;
  RooGaussModel gm("gm1","gauss model scaled bt per-event error",dt,bias,sigma,dterr) ;

  // Construct decay(dt) (x) gauss1(dt|dterr)
  RooRealVar tau("tau","tau",1.548) ;
  RooDecay decay_gm("decay_gm","decay",dt,tau,gm,RooDecay::DoubleSided) ;



  // C o n s t r u c t   f a k e   ' e x t e r n a l '   d a t a    w i t h   p e r - e v e n t   e r r o r
  // ------------------------------------------------------------------------------------------------------

  // Use landau p.d.f to get somewhat realistic distribution with long tail
  RooLandau pdfDtErr("pdfDtErr","pdfDtErr",dterr,RooConst(1),RooConst(0.25)) ;
  RooDataSet* expDataDterr = pdfDtErr.generate(dterr,10000) ;



  // S a m p l e   d a t a   f r o m   c o n d i t i o n a l   d e c a y _ g m ( d t | d t e r r )
  // ---------------------------------------------------------------------------------------------

  // Specify external dataset with dterr values to use decay_dm as conditional p.d.f.
  RooDataSet* data = decay_gm.generate(dt,ProtoData(*expDataDterr)) ;

  

  // F i t   c o n d i t i o n a l   d e c a y _ d m ( d t | d t e r r )
  // ---------------------------------------------------------------------

  // Specify dterr as conditional observable
  decay_gm.fitTo(*data,ConditionalObservables(dterr), Verbose()) ;
  RooNLLVar *nll = new RooNLLVar("nll","-log(L)",decay_gm,*data, ConditionalObservables(dterr));


}