MTTmaxPatternRecognition.cxx

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/*
  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
*/
 
#include "MdtCalibT0/MTTmaxPatternRecognition.h"
 
#include <cmath>
 
#include "AthenaKernel/getMessageSvc.h"
#include "GaudiKernel/MsgStream.h"
#include "TF1.h"
#include "TGraph.h"
#include "TH1.h"
#include "TLine.h"
 
namespace MuonCalib {
 
    inline Double_t myexp(Double_t* x, Double_t* p) { return std::exp(p[0] + p[1] * (x[0] - p[3])) + p[2]; }
 
    bool MTTmaxPatternRecognition::Initialize(TH1F* hist, double t0, const T0MTSettings* settings) {
        m_settings = settings->TMaxSettings();
        m_draw_debug_graph = settings->DrawDebugGraphs();
        m_error = false;
        m_t0 = t0;
        m_error = !m_vbh.Initialize(hist, m_settings->VBHBinContent(), m_settings->MaxBinwidth(), t0 + m_settings->VBHLow());
        if (m_error || m_vbh.GetNumberOfBins() < 2) {
            MsgStream log(Athena::getMessageSvc(), "MTTmaxPatternRecognition");
            log << MSG::WARNING << "Initialize() - Initialization of VBH failed!" << endmsg;
        }
        if (!m_error) estimate_background(hist);
        if (!m_error) estimate_height(hist);
        return !m_error;
    }
 
    // estimate_background( TH1 *hist)  //
 
    bool MTTmaxPatternRecognition::estimate_background(TH1F* hist) {
        // smooth VBH in several steps
        for (double i = 1.0; i <= 4.0; i *= 2.0) {
            for (int j = 0; j < 2; j++)
                if (!m_vbh.Smooth(hist->GetBinWidth(1) / i)) {
                    m_error = true;
                    return false;
                }
        }
        if (m_draw_debug_graph) {
            m_vbh.DenistyGraph()->Write("tmax_density");
            m_vbh.BinWidthGraph()->Write("tmax_binwidth");
            m_vbh.DiffDensityGraph()->Write("tmax_diffdensity");
            m_vbh.DiffBinwidthGraph()->Write("tmax_diffbinwidth");
        }
        // find falling edge - search for steepenst slope in a range of 600 to 800 ns after the t0
        double peak_falling(0.0), peak_falling_slope(-9e9);
        for (unsigned int i = 0; i < m_vbh.GetNumberOfBins() - 1; i++) {
            const VariableBinwidthHistogramBin &bin1(m_vbh.GetBin(i)), &bin2(m_vbh.GetBin(i + 1));
            // select region
            if (bin1.Center() < m_t0 + m_settings->EndMin() || bin1.Center() > m_t0 + m_settings->EndMax()) continue;
            if (bin2.Width() - bin1.Width() > peak_falling_slope && bin2.Right() < hist->GetBinLowEdge(hist->GetNbinsX()) - 10) {
                peak_falling = bin1.Right();
                peak_falling_slope = bin2.Width() - bin1.Width();
            }
        }
        // check region size
        int firstbin = hist->FindBin(peak_falling + m_settings->DistBackground());
        int lastbin = hist->FindBin(m_vbh.GetBin(m_vbh.GetNumberOfBins() - 1).Right());
        if (lastbin - firstbin < m_settings->MinBackgroundBins()) lastbin = hist->GetNbinsX();
        if (lastbin - firstbin < m_settings->MinBackgroundBins()) {
            MsgStream log(Athena::getMessageSvc(), "MTTmaxPatternRecognition");
            log << MSG::WARNING << "estimate_background() - Falling edge is to glose to upper histogram range!" << endmsg;
            m_error = true;
            return false;
        }
        // calcul;ate mean
        m_background = 0.0;
        double n_bins = 0.0;
        if (lastbin > hist->GetNbinsX()) lastbin = hist->GetNbinsX();
        for (int i = firstbin; i <= lastbin; i++) {
            m_background += hist->GetBinContent(i);
            n_bins++;
        }
        // mark selected range
        if (m_draw_debug_graph) {
            (new TLine(hist->GetBinCenter(firstbin), 0, hist->GetBinCenter(firstbin), hist->GetMaximum()))->Write("tmax_back_left");
            (new TLine(hist->GetBinCenter(lastbin), 0, hist->GetBinCenter(lastbin), hist->GetMaximum()))->Write("tmax_back_right");
        }
 
        m_background /= n_bins;
        m_tmax_est = peak_falling;
        m_fit_max = hist->GetBinCenter(lastbin);
        return true;
    }
 
    // estimate_height( TH1 *hist,  double background_min)  //
 
    bool MTTmaxPatternRecognition::estimate_height(TH1F* hist) {
        // get start value for fit
        Double_t left = m_tmax_est - m_settings->DistAB() - m_settings->WidthAB(), right = m_tmax_est - m_settings->DistAB();
        // fit
        TF1* fun = new TF1("myexp", myexp, left, right, 4);
        fun->FixParameter(2, m_background);
        fun->FixParameter(3, m_t0);
        hist->Fit("myexp", "Q0+", "", left, right);
        // store parameters
        m_a = fun->GetParameter(0);
        m_b = fun->GetParameter(1);
        m_fit_min = m_tmax_est - m_settings->DistAB() - m_settings->WidthAB();
        // mark selected range
        if (m_draw_debug_graph) {
            (new TLine(left, 0, left, hist->GetMaximum()))->Write("tmax_height_left");
            (new TLine(right, 0, right, hist->GetMaximum()))->Write("tmax_height_right");
        }
        return true;
    }
 
}  // namespace MuonCalib