//////////////////////////////////////////////////////////////////////////
//
// 'MULTIDIMENSIONAL MODELS' RooFit tutorial macro #310
// 
// Projecting p.d.f and data ranges in continuous observables
//
//
//
// 07/2008 - Wouter Verkerke 
// 
/////////////////////////////////////////////////////////////////////////

#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooProdPdf.h"
#include "RooAddPdf.h"
#include "RooPolynomial.h"
#include "TCanvas.h"
#include "TFile.h"
#include "RooPlot.h"
using namespace RooFit ;

void TestApp_works(){

  // C r e a t e   3 D   p d f   a n d   d a t a 
  // -------------------------------------------
	
	
	
	//if the RooRealVars are declared here, it is possible  to set ranges later:
	RooRealVar x("x","x",-5,5) ;
	RooRealVar y("y","y",-5,5) ;
	RooRealVar z("z","z",-5,5) ;
	
	{
		
	  
		// Create observables
		//RooRealVar x("x","x",-5,5) ;
		//RooRealVar y("y","y",-5,5) ;
		//RooRealVar z("z","z",-5,5) ;

		RooRealVar   *Gauss_mean  = new RooRealVar("Gauss_mean", "mean" , 0.) ;
		RooRealVar   *Gauss_sigma = new RooRealVar("Gauss_sigma", "sigma" , 1.) ;
		
		// Create signal pdf gauss(x)*gauss(y)*gauss(z) 
		RooGaussian gx("gx","gx",x,*Gauss_mean, *Gauss_sigma) ;
		RooGaussian gy("gy","gy",y,*Gauss_mean, *Gauss_sigma) ;
		RooGaussian gz("gz","gz",z,*Gauss_mean, *Gauss_sigma) ;
		RooProdPdf sig("sig","sig",RooArgSet(gx,gy,gz)) ;
		
		// Create background pdf poly(x)*poly(y)*poly(z) 
		RooRealVar   *p1a  = new RooRealVar("p1a", "p1a" , -0.1) ;
		RooRealVar   *p2a  = new RooRealVar("p1b", "p1b" , 0.004) ;
		RooRealVar   *p1b  = new RooRealVar("p2a", "p2a" , 0.1) ;
		RooRealVar   *p2b  = new RooRealVar("p2b", "p2b" , -0.004) ;
		
		RooPolynomial px("px","px",x, RooArgSet(*p1a, *p1b) );
		RooPolynomial py("py","py",y, RooArgSet(*p2a, *p2b) );
		RooPolynomial pz("pz","pz",z) ;
		RooProdPdf bkg("bkg","bkg",RooArgSet(px,py,pz)) ;
		
		// Create composite pdf sig+bkg
		RooRealVar fsig("fsig","signal fraction",0.1,0.,1.) ;
		RooAddPdf *model = new RooAddPdf("model","model",RooArgList(sig,bkg),fsig) ;
		
		RooDataSet* data = model->generate(RooArgSet(x,y,z),20000) ;
		data->SetName("data");
		
		TFile * output = new TFile("output.root", "RECREATE");
		output->cd();
		data->Write();
		model->Write();
		output->Close();
		
	}
	
	
	// Create observables
	//RooRealVar x("x","x",-5,5) ;
	//RooRealVar y("y","y",-5,5) ;
	//RooRealVar z("z","z",-5,5) ;

	TFile *output = new TFile("output.root", "READ");
	output->cd();
	RooDataSet *data2 = (RooDataSet*)output->Get("data");
	RooAddPdf* model2  = (RooAddPdf*)output->Get("model");
	output->Close();
	
	
	
	
	// P r o j e c t   p d f   a n d   d a t a   o n   x
	// -------------------------------------------------
	
	// Make plain projection of data and pdf on x observable
	RooPlot* frame = x.frame(Title("Projection of 3D data and pdf on X"),Bins(40)) ;
	data2->plotOn(frame) ;
	model2->plotOn(frame) ;
	
	
	
	// P r o j e c t   p d f   a n d   d a t a   o n   x   i n   s i g n a l   r a n g e
	// ----------------------------------------------------------------------------------
	
	// Define signal region in y and z observables
	y.setRange("sigRegion",-1,1) ;
	z.setRange("sigRegion",-1,1) ;
	
	// Make plot frame
	RooPlot* frame2 = x.frame(Title("Same projection on X in signal range of (Y,Z)"),Bins(40)) ;
	
	// Plot subset of data in which all observables are inside "sigRegion"
	// For observables that do not have an explicit "sigRegion" range defined (e.g. observable)
	// an implicit definition is used that is identical to the full range (i.e. [-5,5] for x)
	data2->plotOn(frame2,CutRange("sigRegion")) ;
	
	// Project model on x, integrating projected observables (y,z) only in "sigRegion"
	model2->plotOn(frame2,ProjectionRange("sigRegion")) ;
	
	
	TCanvas *c = new TCanvas("test","test",1200,600);
	c->Divide(2,1);
	c->cd(1);
	frame->Draw();
	c->cd(2);
	frame2->Draw();
	c->SaveAs("test.eps");
	
	delete data2 ;
	
	return;
	
}