/// \file
/// \ingroup tutorial_roofit
/// \notebook -js
///
/// Organisation and simultaneous fits: reading and using a workspace
///
///  The input file for this macro is generated by rf502_wspacewrite.C
///
/// \macro_image
/// \macro_output
/// \macro_code
///
/// \date 07/2008
/// \author Wouter Verkerke

#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooConstVar.h"
#include "RooChebychev.h"
#include "RooAddPdf.h"
#include "RooWorkspace.h"
#include "RooPlot.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TFile.h"
#include "TH1.h"
using namespace RooFit;

void rf503_wspaceread()
{
   // R e a d   w o r k s p a c e   f r o m   f i l e
   // -----------------------------------------------

   // Open input file with workspace (generated by rf14_wspacewrite)
   TFile *f = new TFile("rf502_workspace.root");

   // Retrieve workspace from file
   RooWorkspace *w = (RooWorkspace *)f->Get("w");

   // R e t r i e v e   p d f ,   d a t a   f r o m   w o r k s p a c e
   // -----------------------------------------------------------------

   // Retrieve x,model and data from workspace
   RooRealVar *x = w->var("x");
   RooAbsPdf *model = w->pdf("model");
   RooAbsData *data = w->data("modelData");

   // Print structure of composite p.d.f.
   model->Print("t");

   // F i t   m o d e l   t o   d a t a ,   p l o t   m o d e l
   // ---------------------------------------------------------

   // Fit model to data
   model->fitTo(*data);

   // Plot data and PDF overlaid
   RooPlot *xframe = x->frame(Title("Model and data read from workspace"));
   data->plotOn(xframe);
   model->plotOn(xframe);

   // Overlay the background component of model with a dashed line
   model->plotOn(xframe, Components("bkg"), LineStyle(kDashed));

   // Overlay the background+sig2 components of model with a dotted line
   model->plotOn(xframe, Components("bkg,sig2"), LineStyle(kDotted));

   // Draw the frame on the canvas
   new TCanvas("rf503_wspaceread", "rf503_wspaceread", 600, 600);
   gPad->SetLeftMargin(0.15);
   xframe->GetYaxis()->SetTitleOffset(1.4);
   xframe->Draw();
}