FitAwmi.C File Reference

Detailed Description

This macro fits the source spectrum using the AWMI algorithm from the "TSpectrumFit" class ("TSpectrum" class is used to find peaks).

To try this macro, in a ROOT (5 or 6) prompt, do:

root > .x FitAwmi.C

or:

root > .x FitAwmi.C++
root > FitAwmi(); // re-run with another random set of peaks

created -9.82 53.1923 8
created -9.46 66.4904 10
created -9.1 13.2981 2
created -8.74 66.4904 10
created -8.38 39.8942 6
created -8.02 59.8413 9
created -7.66 59.8413 9
created -7.3 26.5962 4
created -6.94 33.2452 5
created -6.58 46.5433 7
created -6.22 19.9471 3
created -5.86 26.5962 4
created -5.5 66.4904 10
created -5.14 26.5962 4
created -4.78 6.64904 1
created -4.42 13.2981 2
created -4.06 59.8413 9
created -3.7 59.8413 9
created -3.34 46.5433 7
created -2.98 66.4904 10
created -2.62 59.8413 9
created -2.26 39.8942 6
created -1.9 46.5433 7
created -1.54 66.4904 10
created -1.18 59.8413 9
created -0.82 26.5962 4
created -0.46 13.2981 2
created -0.1 53.1923 8
created 0.26 26.5962 4
created 0.62 66.4904 10
created 0.98 26.5962 4
created 1.34 26.5962 4
created 1.7 33.2452 5
created 2.06 53.1923 8
created 2.42 66.4904 10
created 2.78 26.5962 4
created 3.14 6.64904 1
created 3.5 66.4904 10
created 3.86 46.5433 7
created 4.22 53.1923 8
created 4.58 59.8413 9
created 4.94 66.4904 10
created 5.3 59.8413 9
created 5.66 19.9471 3
created 6.02 39.8942 6
created 6.38 26.5962 4
created 6.74 26.5962 4
created 7.1 66.4904 10
created 7.46 26.5962 4
created 7.82 26.5962 4
created 8.18 39.8942 6
created 8.54 26.5962 4
created 8.9 6.64904 1
created 9.26 46.5433 7
created 9.62 33.2452 5
the total number of created peaks = 55 with sigma = 0.06
the total number of found peaks = 55 with sigma = 0.0600004 (+-1.10092e-05)
fit chi^2 = 1.9216e-06
found -9.46 (+-0.000112425) 66.4904 (+-0.12307) 10.0001 (+-0.000620791)
found -8.74 (+-0.000112311) 66.4903 (+-0.123054) 10.0001 (+-0.000620713)
found -5.5 (+-0.000112367) 66.4903 (+-0.12306) 10.0001 (+-0.000620743)
found -2.98 (+-0.000112878) 66.4906 (+-0.123128) 10.0001 (+-0.000621086)
found -1.54 (+-0.000112878) 66.4906 (+-0.123128) 10.0001 (+-0.000621086)
found 0.62 (+-0.000112367) 66.4903 (+-0.12306) 10.0001 (+-0.000620743)
found 2.42 (+-0.000112624) 66.4904 (+-0.123095) 10.0001 (+-0.000620916)
found 3.5 (+-0.000112221) 66.4903 (+-0.123045) 10.0001 (+-0.000620665)
found 4.94 (+-0.000112985) 66.4907 (+-0.123143) 10.0001 (+-0.000621159)
found 7.1 (+-0.000112367) 66.4903 (+-0.12306) 10.0001 (+-0.000620743)
found -7.66 (+-0.000118856) 59.8415 (+-0.116795) 9.00009 (+-0.000589139)
found -3.7 (+-0.00011908) 59.8416 (+-0.116822) 9.00011 (+-0.000589273)
found -2.62 (+-0.000119065) 59.8416 (+-0.11682) 9.00011 (+-0.000589266)
found -1.18 (+-0.000118908) 59.8415 (+-0.116802) 9.00009 (+-0.000589172)
found 4.58 (+-0.000119192) 59.8417 (+-0.116836) 9.00012 (+-0.000589344)
found 5.3 (+-0.00011881) 59.8415 (+-0.11679) 9.00009 (+-0.000589115)
found -8.02 (+-0.000119014) 59.8416 (+-0.116814) 9.0001 (+-0.000589233)
found -4.06 (+-0.000118637) 59.8414 (+-0.11677) 9.00007 (+-0.000589015)
found -9.82 (+-0.000126229) 53.1924 (+-0.110124) 8.00007 (+-0.00055549)
found -0.0999998 (+-0.000125558) 53.1922 (+-0.110062) 8.00004 (+-0.000555174)
found 2.06 (+-0.000126324) 53.1926 (+-0.110143) 8.0001 (+-0.000555587)
found 4.22 (+-0.000126422) 53.1926 (+-0.110154) 8.00011 (+-0.000555639)
found -3.34 (+-0.000135511) 46.5438 (+-0.103075) 7.00013 (+-0.000519932)
found 3.86 (+-0.000135441) 46.5437 (+-0.103068) 7.00012 (+-0.000519897)
found -6.58 (+-0.000134583) 46.5433 (+-0.102986) 7.00005 (+-0.000519481)
found -1.9 (+-0.000135283) 46.5437 (+-0.103053) 7.00011 (+-0.000519819)
found 9.26 (+-0.000134225) 46.5432 (+-0.102955) 7.00004 (+-0.000519325)
found -8.38 (+-0.000146579) 39.8948 (+-0.0954471) 6.00013 (+-0.000481455)
found -2.26 (+-0.000146339) 39.8947 (+-0.0954264) 6.00011 (+-0.000481351)
found 6.02 (+-0.000145399) 39.8943 (+-0.0953485) 6.00005 (+-0.000480958)
found 8.18 (+-0.000145539) 39.8943 (+-0.0953596) 6.00005 (+-0.000481014)
found -6.94 (+-0.000160011) 33.2455 (+-0.0870914) 5.00007 (+-0.000439308)
found 1.7 (+-0.000160112) 33.2455 (+-0.0870987) 5.00008 (+-0.000439344)
found 9.62 (+-0.000158583) 33.2455 (+-0.0870104) 5.00008 (+-0.000438899)
found -7.3 (+-0.000179649) 26.5966 (+-0.0779401) 4.00009 (+-0.000393146)
found -5.14 (+-0.000178783) 26.5965 (+-0.0778954) 4.00007 (+-0.000392921)
found -0.820001 (+-0.000179028) 26.5965 (+-0.0779065) 4.00007 (+-0.000392977)
found 0.26 (+-0.000180162) 26.5968 (+-0.07797) 4.00012 (+-0.000393297)
found 0.979999 (+-0.000179582) 26.5966 (+-0.0779368) 4.00009 (+-0.00039313)
found 1.34 (+-0.000178964) 26.5964 (+-0.0779003) 4.00006 (+-0.000392946)
found 2.78 (+-0.000178783) 26.5965 (+-0.0778954) 4.00007 (+-0.000392921)
found 6.38 (+-0.000179112) 26.5964 (+-0.0779089) 4.00007 (+-0.000392989)
found 6.74 (+-0.000179582) 26.5966 (+-0.0779368) 4.00009 (+-0.00039313)
found 7.46 (+-0.000179582) 26.5966 (+-0.0779368) 4.00009 (+-0.00039313)
found 7.82 (+-0.000179112) 26.5964 (+-0.0779089) 4.00007 (+-0.000392989)
found 8.54 (+-0.000178319) 26.5963 (+-0.0778674) 4.00005 (+-0.00039278)
found -5.86 (+-0.000179381) 26.5966 (+-0.0779259) 4.00009 (+-0.000393075)
found -6.22 (+-0.000207542) 19.9475 (+-0.0675025) 3.00007 (+-0.000340497)
found 5.66 (+-0.000208252) 19.9476 (+-0.067534) 3.0001 (+-0.000340656)
found -9.1 (+-0.00025734) 13.2989 (+-0.0552121) 2.00014 (+-0.000278502)
found -0.459999 (+-0.000255514) 13.2985 (+-0.0551556) 2.00008 (+-0.000278216)
found -4.42 (+-0.00025424) 13.2984 (+-0.0551215) 2.00007 (+-0.000278044)
found 3.14 (+-0.000365357) 6.64962 (+-0.0390651) 1.0001 (+-0.000197053)
found 8.9 (+-0.000364287) 6.64949 (+-0.0390469) 1.00007 (+-0.000196961)
found -4.78 (+-0.000361351) 6.64926 (+-0.0390009) 1.00004 (+-0.000196729)

 
#include "TROOT.h"
#include "TMath.h"
#include "TRandom.h"
#include "TH1.h"
#include "TF1.h"
#include "TCanvas.h"
#include "TSpectrum.h"
#include "TSpectrumFit.h"
#include "TPolyMarker.h"
#include "TList.h"
 
#include <iostream>
 
TH1F *FitAwmi_Create_Spectrum(void)
{
   Int_t nbins = 1000;
   Double_t xmin = -10., xmax = 10.;
   delete gROOT->FindObject("h"); // prevent "memory leak"
   TH1F *h = new TH1F("h", "simulated spectrum", nbins, xmin, xmax);
   h->SetStats(kFALSE);
   TF1 f("f", "TMath::Gaus(x, [0], [1], 1)", xmin, xmax);
   // f.SetParNames("mean", "sigma");
   gRandom->SetSeed(0); // make it really random
   // create well separated peaks with exactly known means and areas
   // note: TSpectrumFit assumes that all peaks have the same sigma
   Double_t sigma = (xmax - xmin) / Double_t(nbins) * Int_t(gRandom->Uniform(2., 6.));
   Int_t npeaks = 0;
   while (xmax > (xmin + 6. * sigma)) {
      npeaks++;
      xmin += 3. * sigma; // "mean"
      f.SetParameters(xmin, sigma);
      Double_t area = 1. * Int_t(gRandom->Uniform(1., 11.));
      h->Add(&f, area, ""); // "" ... or ... "I"
      std::cout << "created " << xmin << " " << (area / sigma / TMath::Sqrt(TMath::TwoPi())) << " " << area
                << std::endl;
      xmin += 3. * sigma;
   }
   std::cout << "the total number of created peaks = " << npeaks << " with sigma = " << sigma << std::endl;
   return h;
}
 
void FitAwmi(void)
{
 
   TH1F *h = FitAwmi_Create_Spectrum();
 
   TCanvas *cFit = ((TCanvas *)(gROOT->GetListOfCanvases()->FindObject("cFit")));
   if (!cFit)
      cFit = new TCanvas("cFit", "cFit", 10, 10, 1000, 700);
   else
      cFit->Clear();
   h->Draw("L");
   Int_t i, nfound, bin;
   Int_t nbins = h->GetNbinsX();
 
   Double_t *source = new Double_t[nbins];
   Double_t *dest = new Double_t[nbins];
 
   for (i = 0; i < nbins; i++)
      source[i] = h->GetBinContent(i + 1);
   TSpectrum *s = new TSpectrum(); // note: default maxpositions = 100
   // searching for candidate peaks positions
   nfound = s->SearchHighRes(source, dest, nbins, 2., 2., kFALSE, 10000, kFALSE, 0);
   // filling in the initial estimates of the input parameters
   Bool_t *FixPos = new Bool_t[nfound];
   Bool_t *FixAmp = new Bool_t[nfound];
   for (i = 0; i < nfound; i++)
      FixAmp[i] = FixPos[i] = kFALSE;
 
   Double_t *Pos, *Amp = new Double_t[nfound]; // ROOT 6
 
   Pos = s->GetPositionX(); // 0 ... (nbins - 1)
   for (i = 0; i < nfound; i++) {
      bin = 1 + Int_t(Pos[i] + 0.5); // the "nearest" bin
      Amp[i] = h->GetBinContent(bin);
   }
   TSpectrumFit *pfit = new TSpectrumFit(nfound);
   pfit->SetFitParameters(0, (nbins - 1), 1000, 0.1, pfit->kFitOptimChiCounts, pfit->kFitAlphaHalving, pfit->kFitPower2,
                          pfit->kFitTaylorOrderFirst);
   pfit->SetPeakParameters(2., kFALSE, Pos, FixPos, Amp, FixAmp);
   // pfit->SetBackgroundParameters(source[0], kFALSE, 0., kFALSE, 0., kFALSE);
   pfit->FitAwmi(source);
   Double_t *Positions = pfit->GetPositions();
   Double_t *PositionsErrors = pfit->GetPositionsErrors();
   Double_t *Amplitudes = pfit->GetAmplitudes();
   Double_t *AmplitudesErrors = pfit->GetAmplitudesErrors();
   Double_t *Areas = pfit->GetAreas();
   Double_t *AreasErrors = pfit->GetAreasErrors();
   delete gROOT->FindObject("d"); // prevent "memory leak"
   TH1F *d = new TH1F(*h);
   d->SetNameTitle("d", "");
   d->Reset("M");
   for (i = 0; i < nbins; i++)
      d->SetBinContent(i + 1, source[i]);
   Double_t x1 = d->GetBinCenter(1), dx = d->GetBinWidth(1);
   Double_t sigma, sigmaErr;
   pfit->GetSigma(sigma, sigmaErr);
 
   // current TSpectrumFit needs a sqrt(2) correction factor for sigma
   sigma /= TMath::Sqrt2();
   sigmaErr /= TMath::Sqrt2();
   // convert "bin numbers" into "x-axis values"
   sigma *= dx;
   sigmaErr *= dx;
 
   std::cout << "the total number of found peaks = " << nfound << " with sigma = " << sigma << " (+-" << sigmaErr << ")"
             << std::endl;
   std::cout << "fit chi^2 = " << pfit->GetChi() << std::endl;
   for (i = 0; i < nfound; i++) {
      bin = 1 + Int_t(Positions[i] + 0.5); // the "nearest" bin
      Pos[i] = d->GetBinCenter(bin);
      Amp[i] = d->GetBinContent(bin);
 
      // convert "bin numbers" into "x-axis values"
      Positions[i] = x1 + Positions[i] * dx;
      PositionsErrors[i] *= dx;
      Areas[i] *= dx;
      AreasErrors[i] *= dx;
 
      std::cout << "found " << Positions[i] << " (+-" << PositionsErrors[i] << ") " << Amplitudes[i] << " (+-"
                << AmplitudesErrors[i] << ") " << Areas[i] << " (+-" << AreasErrors[i] << ")" << std::endl;
   }
   d->SetLineColor(kRed);
   d->SetLineWidth(1);
   d->Draw("SAME L");
   TPolyMarker *pm = ((TPolyMarker *)(h->GetListOfFunctions()->FindObject("TPolyMarker")));
   if (pm) {
      h->GetListOfFunctions()->Remove(pm);
      delete pm;
   }
   pm = new TPolyMarker(nfound, Pos, Amp);
   h->GetListOfFunctions()->Add(pm);
   pm->SetMarkerStyle(23);
   pm->SetMarkerColor(kRed);
   pm->SetMarkerSize(1);
   // cleanup
   delete pfit;
   delete[] Amp;
   delete[] FixAmp;
   delete[] FixPos;
   delete s;
   delete[] dest;
   delete[] source;
   return;
}

Author

Definition in file FitAwmi.C.