class HepDataMCPlotter: public TTask

 DATA/MC Histogram Plotter

 Task for creating and plotting lists of stacked or overlayed
 MC histograms with DATA on top

 * The same binning for all histograms is required
 * Until now only 1d histograms are supported

 The plots are made from input files containing histograms for the
 various MC samples (signal + bckg) as well as DATA. Here, it is
 assumed that the directory and histogram structure is the same for
 each input file. The samples will be normalized w.r.t. the given
 luminosities

 The list of plots can be exported in two ways (combination
 possible):

 (1) All plots are stored in a single .root file. Here, the
 directory structure of the input files is preserved.

 (2) Export to various graphical formats like eps, ps, pdf, png or C
 macro. Since the number of plots is usually high, the directory
 structure of the input files is mapped onto the file system and the
 image files will be stored in their respective directories.  In
 case of an already existing version of the directory tree a backup
 copy is created first under the name $ExportDir_backup where
 $ExportDir indicates the name of the export directory given by
 SetExportDir().

 Samples can be combined in groups for better drawing. See the
 examples below. The way of drawing can be changed afterwards via
 HepDataMCPlot::SetGroupHistograms().

 Legend: The default behaviour is not to draw a legend inside the
 plots since the number of samples is nornmally high and therefore
 the legend would fit badly into the pad. (However, this behaviour
 can be changed with the help of the SetLegend() member function,
 accessible alspo from the TBrowser) It is recommended to draw the
 legend in an additional pad. In case of an exported .root file this
 is easily possible by using the HepDataMCPlot::DrawLegendPad()
 function (can also be used from the TBrowser). In case of exported
 graphical files an additional file containing only the legend is
 created in toplevel export directory under the name Legend.eps etc.

 Example 1 (ungrouped histograms):
 {
     HepDataMCPlotter *pl = new HepDataMCPlotter("single-top", "Single-Top Analysis");
     pl->SetExportDir("~/atlas/APlusPlus/libSingleTop/hist/tChannelAnalysis/test");
     pl->SetLumiDATA(100.);
     pl->AddMCSample("$LIBSINGLETOP/hist/tChannelAnalysis/tchannel_enu.root",
                     "MC single-top t-channel e#nu", 120., kOrange);
     pl->AddMCSample("$LIBSINGLETOP/hist/tChannelAnalysis/tchannel_munu.root",
                     "MC single-top t-channel #mu#nu", 130., kRed);
     pl->AddMCSample("$LIBSINGLETOP/hist/tChannelAnalysis/tchannel_taunu.root",
                     "MC single-top t-channel #tau#nu", 110., kMagenta);
     pl->AddMCSample("$LIBSINGLETOP/hist/tChannelAnalysis/schannel_enu.root",
                     "MC single-top s-channel e#nu", 120., kBlue);
     pl->AddMCSample("$LIBSINGLETOP/hist/tChannelAnalysis/schannel_muunu.root",
                     "MC single-top s-channel #mu#nu", 120., kCyan);
     pl->AddMCSample("$LIBSINGLETOP/hist/tChannelAnalysis/Wtproduction.root",
                     "MC single-top Wt production", 90., kGreen);
     gROOT->GetListOfBrowsables()->Add(pl);
     new TBrowser;
 }


 Example 2 (grouped histograms):
 {
     HepDataMCPlotter *pl_test = new HepDataMCPlotter("DATA-MC plotter", "Create all Data-MC plots");
     pl_test->SetWorkingDir("$LIBSINGLETOP/hist/test/plots_datamc");
     pl_test->SetLumiDATA(100.);

     // ttbar
     pl_test->AddMCFolder("ttbar", "ttbar lnln", kRed);
     (pl_test->AddMCSample("ttbar", "$LIBSINGLETOP/hist/test/ttbar_lnln_np0_hists.root",
                           "MC ttbar, Np0", 160., kRed-4))->SetLumi(160.);
     (pl_test->AddMCSample("ttbar", "$LIBSINGLETOP/hist/test/ttbar_lnln_np1_hists.root",
                           "MC ttbar, Np1", 180., kRed-7))->SetLumi(180.);
     (pl_test->AddMCSample("ttbar", "$LIBSINGLETOP/hist/test/ttbar_lnln_np2_hists.root",
                           "MC ttbar, Np2", 150., kRed-9))->SetLumi(150.);

     // Z+jets
     pl_test->AddMCFolder("Zjets", "Z+jets", kBlue);
     (pl_test->AddMCSample("Zjets", "$LIBSINGLETOP/hist/test/zee_np0_hists.root",
                           "MC Zee, Np0", 70., kBlue-4))->SetLumi(70.);
     (pl_test->AddMCSample("Zjets", "$LIBSINGLETOP/hist/test/zee_np1_hists.root",
                           "MC Zee, Np1", 60., kBlue-7))->SetLumi(60.);
     (pl_test->AddMCSample("Zjets", "$LIBSINGLETOP/hist/test/zmumu_np0_hists.root",
                           "MC Zmumu, Np0", 90., kBlue-9))->SetLumi(90.);
     (pl_test->AddMCSample("Zjets", "$LIBSINGLETOP/hist/test/zmumu_np1_hists.root",
                           "MC Zmumu, Np1", 110., kBlue-10))->SetLumi(110.);
     (pl_test->AddMCSample("Zjets", "$LIBSINGLETOP/hist/test/zmumu_np2_hists.root",
                           "MC Zmumu, Np2", 120., kBlue-8))->SetLumi(120.);
 }



 Author: Oliver Maria Kind <mailto: kind@mail.desy.de>
 Update: $Id: HepDataMCPlotter.cxx,v 1.32 2017/07/28 09:34:11 kaphle Exp $
 Copyright: 2009 (C) Oliver Maria Kind