//////////////////////////////////////////////////////////////////////////
//
// 'SPECIAL PDFS' RooFit tutorial macro #705
// 
// Linear interpolation between p.d.f shapes using the 'Alex Read' algorithm
//
//
//
// 07/2008 - Wouter Verkerke 
// 
/////////////////////////////////////////////////////////////////////////

#ifndef __CINT__
#include "RooGlobalFunc.h"
#endif
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooConstVar.h"
#include "RooPolynomial.h"
#include "RooIntegralMorph.h"
#include "RooNLLVar.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
#include "TH1.h"
using namespace RooFit ;


void rf705_linearmorph()
{
  // C r e a t e   e n d   p o i n t   p d f   s h a p e s
  // ------------------------------------------------------

  // Observable
  Int_t range = 150000;
  RooRealVar x("x","x",-1*range,range) ;

  // Lower end point shape: a Gaussian
  //RooRealVar g1mean("g1mean","g1mean",-10) ;
  RooGaussian g1("g1","g1",x,RooConst(0),RooConst(100)) ;
  RooGaussian g2("g2","g2",x,RooConst(0),RooConst(10)) ;
 
  // C r e a t e   i n t e r p o l a t i n g   p d f 
  // -----------------------------------------------

  // Create interpolation variable
  RooRealVar alpha("alpha","alpha",0,1.0) ;

  // Specify sampling density on observable and interpolation variable
  x.setBins(range,"cache") ;
  alpha.setBins(50,"cache") ;

  // Construct interpolating pdf in (x,a) represent g1(x) at a=a_min
  // and g2(x) at a=a_max
  RooIntegralMorph lmorph("lmorph","lmorph",g1,g2,x,alpha) ;


  // P l o t   i n t e r p o l a t i n g   p d f   a t   v a r i o u s   a l p h a 
  // -----------------------------------------------------------------------------

  // Show end points as blue curves
  RooPlot* frame1 = x.frame(-200,200) ;
  g1.plotOn(frame1) ;
  g2.plotOn(frame1) ;

  // Show interpolated shapes in red
  alpha.setVal(0.125) ;
  lmorph.plotOn(frame1,LineColor(kRed)) ;
  alpha.setVal(0.25) ;
  lmorph.plotOn(frame1,LineColor(kRed)) ;
  alpha.setVal(0.375) ;
  lmorph.plotOn(frame1,LineColor(kRed)) ;
  alpha.setVal(0.50) ;
  lmorph.plotOn(frame1,LineColor(kRed)) ;
  alpha.setVal(0.625) ;
  lmorph.plotOn(frame1,LineColor(kRed)) ;
  alpha.setVal(0.75) ;
  lmorph.plotOn(frame1,LineColor(kRed)) ;
  alpha.setVal(0.875) ;
  lmorph.plotOn(frame1,LineColor(kRed)) ;
  alpha.setVal(0.95) ;
  lmorph.plotOn(frame1,LineColor(kRed)) ;




  TCanvas* c = new TCanvas("rf705_linearmorph","rf705_linearmorph",800,800) ;
  c->cd() ; gPad->SetLeftMargin(0.15) ; frame1->GetYaxis()->SetTitleOffset(1.6) ; frame1->Draw() ;
  
  
  return ;

}