{

//
// An example to draw various variables in either the Merit or SVAC ntuple!
// Author: Chen, Xin (xchen@slac.stanford.edu)
// Comments by anders :-) 
//


//
// To run this macro, do: root drawMeritSvac.C
// Or if you are already in ROOT: .x drawMeritSvac.C
//


gROOT->Reset();

//
// Name of the Merit ntuple file you want to look at:
// This is a integrated tracker run (real data)!
//
TFile* f1 = new TFile("/nfs/farm/g/glast/u01/svac_workshop/Workshop-3/Data/GlastRelease_v6r2p1-AdditionalCAL/Run-140001338/140001338_merit.root");


//
// 'MeritTuple' is the name of the Root tree in the Merit ntuple and 
// automatically becomes a pointer to that tree.
// Can also explicitly do: 
//TTree *MeritTuple = (TTree*) f1.Get("MeritTuple");
//

//
// Make the Merit and SVAC Root trees 'friends' so that we 
// easily can mix variables from both ntuples:
// 'Output' is the name of the tree in the SVAC ntuple.
//
MeritTuple->AddFriend("Output","/nfs/farm/g/glast/u12/EM2/rootData/398000371/calib-v1r0/svacRoot/emRootv0r0/svacTuple-EM2-v1r0_398000371_svac_svac.root");




//
// First plot: Average number of clusters per Si plane!
//

// Define the canvas:
TCanvas* c1 = new TCanvas;
// Canvas characteristics: Only one histogram in this canvas.
c1->Divide(1,1);
gPad->SetBorderMode(0);
gPad->SetFillColor(10);
// Use log scale:
gPad->SetLogy();
// Fill plot with red:
MeritTuple->SetFillColor(2);
// Draw a plot of average number of clusters per Si plane:
// We only plot the clusters for the cut 'TkrNumClusters>0'.
// Note that 'TkrNumClusters' is part of the SVAC ntuple. 
// We plot it like it was part of Merit using the same pointer 'MeritTuple'.
// Also note that 'TkrNumClusters' is in fact an array. Here Root automatically 
// sums up all the entries in the array and plots the sum.
// We only look at the first 100 events here.
MeritTuple->Draw("TkrNumClusters","TkrNumClusters>0","","100");
 

// More details about the Merit and SVAC ntuple variables are found 
// in the Merit ntuple decsription available from the main 
// Instrument Analysis page. 


//
// Draw a profile plot of number of clusters in a 
// plane vs. reconstructed z direction:
//
TCanvas* c2 = new TCanvas;
c2->Divide(1,1);
gPad->SetBorderMode(0);
gPad->SetFillColor(10);
// Plotting SVAC variables with a cut made from both SVAC and Merit ('TkrRadLength') variables.
// Here we use a more complicated cut. '&&' is standard C++ syntax for 'and'.
// Use '||' for 'or'.
// We only look at the first 5000 events here.
MeritTuple->Draw("TkrNumClusters:VtxZDir","TkrNumTracks>0 && TkrNumClusters>0 && TkrRadLength>0.5", "prof","5000");


//
// Draw a plot of reconstructed X position against reconstructed Y position:
//
TCanvas* c3 = new TCanvas;
c3->Divide(1,1);
gPad->SetBorderMode(0);
gPad->SetFillColor(10);
MeritTuple->SetFillColor(2);
MeritTuple->Draw("VtxY0:VtxX0","TkrNumTracks>0 && abs(VtxY0)<1000 && abs(VtxX0)<1000");

}