source: trunk/MagicSoft/Mars/mmontecarlo/MCollArea.cc@ 852

/* ======================================================================== *\
!
! *
! * This file is part of MARS, the MAGIC Analysis and Reconstruction
! * Software. It is distributed to you in the hope that it can be a useful
! * and timesaving tool in analysing Data of imaging Cerenkov telescopes.
! * It is distributed WITHOUT ANY WARRANTY.
! *
! * Permission to use, copy, modify and distribute this software and its
! * documentation for any purpose is hereby granted without fee,
! * provided that the above copyright notice appear in all copies and
! * that both that copyright notice and this permission notice appear
! * in supporting documentation. It is provided "as is" without express
! * or implied warranty.
! *
!
!
!   Author(s): Harald Kornmayer 1/2001 (harald@mppmu.mpg.de)
!              Thomas Bretz  12/2000 (tbretz@uni-sw.gwdg.de)
!
!   Copyright: MAGIC Software Development, 2000-2001
!
!
\* ======================================================================== */

#include "MCollArea.h" 

#include <MLog.h>
#include <TH2.h> 

ClassImp(MCollArea)



MCollArea::MCollArea(const char *name, const char *title) 
{ 
    //
    //   default constructor
    //

    //   initialize the histogram for the distribution r vs E
    //
    //   we set the energy range from 1 Gev to 10000 GeV (in log 5 orders
    //   of magnitude) and for each order we take 10 subdivision --> 50 xbins
    //
    //   we set the radius range from 0 m to 500 m with 10 m bin --> 50 ybins

  
    *fName  = name  ? name  : "MCollArea";
    *fTitle = title ? title : "Data to Calculate Coll-Area";


    fHistAll = new TH2D("collAreaAll", "all showers - Radius vs log(E) distribution",
                        50, 0., 5.,
                        50, 0., 500. ) ;

    fHistSel = new TH2D("collAreaSel", "selected showers - Radius vs log(E) distribution",
                        50, 0., 5.,
                        50, 0., 500. ) ;

    fHistCol = new TH1D("collArea", "Collection Area",
                        50, 0., 5.) ;

}

MCollArea::~MCollArea()
{
    delete fHistAll ;
    delete fHistSel ;
    delete fHistCol ;
}

void MCollArea::FillAll(Float_t log10E, Float_t radius)
{
    fHistAll->Fill(log10E, radius ) ;
}

void MCollArea::FillSel(Float_t log10E, Float_t radius)
{
    fHistSel->Fill(log10E, radius ) ;
}

void MCollArea::DrawAll()
{
    fHistAll->Draw() ;
}

void MCollArea::DrawSel()
{
    fHistSel->Draw() ;
}

void MCollArea::Draw(Option_t* option)
{
    fHistCol->Draw(option) ;
}

void MCollArea::CalcEfficiency()
{
    // Description!

    //
    //  first of all calculate the efficency
    //  do it here by hand to get the right error of efficency
    //
    const Int_t iBinx = ((TAxis *)fHistSel->GetXaxis())->GetNbins();
    const Int_t iBiny = ((TAxis *)fHistSel->GetYaxis())->GetNbins();

    for (Int_t ix=1; ix<=iBiny; ix++ )
    {
        for (Int_t iy=1; iy<=iBiny; iy++ )
        {
            const Float_t N    = fHistSel->GetCellContent(ix, iy);
            const Float_t Nall = fHistAll->GetCellContent(ix, iy);

            if (Nall <= 0)
                continue;

            const Double_t eff = N / Nall ;
            const Double_t err = sqrt(Nall + Nall*N - N*N - N) / (Nall*Nall);

            fHistSel->SetCellContent(ix, iy, eff);
            fHistSel->SetCellError(ix, iy, err);
        }
    }

    //
    //  now calculate the Collection area for different
    //  energies
    //
    for (Int_t ix=1; ix<=iBiny; ix++ )
    {
        Double_t errA = 0;
        Double_t colA = 0;

        for (Int_t iy=1; iy<=iBiny; iy++ )
        {
            const Double_t r1  = ((TAxis *)fHistSel->GetYaxis())->GetBinLowEdge(iy);
            const Double_t r2  = ((TAxis *)fHistSel->GetYaxis())->GetBinLowEdge(iy+1);

            const Double_t A   = kPI * (r2*r2 - r1*r1);

            const Double_t eff = fHistSel->GetCellContent(ix, iy);
            const Double_t err = fHistSel->GetCellError(ix, iy);

            colA += eff*A;
            errA += (A*A) * err * err;
        }

        fHistCol->SetBinContent(ix, colA);
        fHistCol->SetBinError(ix, sqrt(errA));
    }
}