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 33.2452 5
created -9.46 39.8942 6
created -9.1 6.64904 1
created -8.74 19.9471 3
created -8.38 6.64904 1
created -8.02 39.8942 6
created -7.66 6.64904 1
created -7.3 13.2981 2
created -6.94 13.2981 2
created -6.58 59.8413 9
created -6.22 53.1923 8
created -5.86 39.8942 6
created -5.5 59.8413 9
created -5.14 6.64904 1
created -4.78 59.8413 9
created -4.42 19.9471 3
created -4.06 46.5433 7
created -3.7 6.64904 1
created -3.34 33.2452 5
created -2.98 6.64904 1
created -2.62 59.8413 9
created -2.26 33.2452 5
created -1.9 13.2981 2
created -1.54 59.8413 9
created -1.18 39.8942 6
created -0.82 13.2981 2
created -0.46 33.2452 5
created -0.1 26.5962 4
created 0.26 53.1923 8
created 0.62 6.64904 1
created 0.98 6.64904 1
created 1.34 19.9471 3
created 1.7 39.8942 6
created 2.06 19.9471 3
created 2.42 19.9471 3
created 2.78 39.8942 6
created 3.14 59.8413 9
created 3.5 33.2452 5
created 3.86 13.2981 2
created 4.22 39.8942 6
created 4.58 53.1923 8
created 4.94 26.5962 4
created 5.3 26.5962 4
created 5.66 26.5962 4
created 6.02 46.5433 7
created 6.38 33.2452 5
created 6.74 26.5962 4
created 7.1 19.9471 3
created 7.46 13.2981 2
created 7.82 33.2452 5
created 8.18 19.9471 3
created 8.54 6.64904 1
created 8.9 46.5433 7
created 9.26 66.4904 10
created 9.62 66.4904 10
the total number of created peaks = 55 with sigma = 0.06
the total number of found peaks = 55 with sigma = 0.0600004 (+-1.79196e-05)
fit chi^2 = 3.80976e-06
found 9.26 (+-0.000159005) 66.4907 (+-0.17338) 10.0001 (+-0.000874566)
found 9.62 (+-0.000157666) 66.4908 (+-0.173229) 10.0001 (+-0.000873805)
found -6.58 (+-0.00016697) 59.8414 (+-0.164409) 9.00007 (+-0.000829312)
found -5.5 (+-0.000166561) 59.8412 (+-0.164362) 9.00005 (+-0.000829077)
found -4.78 (+-0.000166208) 59.8411 (+-0.16432) 9.00003 (+-0.000828866)
found -2.62 (+-0.000166459) 59.8412 (+-0.16435) 9.00004 (+-0.000829015)
found -1.54 (+-0.000166793) 59.8413 (+-0.164387) 9.00005 (+-0.000829202)
found 3.14 (+-0.000167217) 59.8414 (+-0.164435) 9.00007 (+-0.000829446)
found -6.22 (+-0.000177904) 53.1926 (+-0.15509) 8.0001 (+-0.000782309)
found 0.26 (+-0.000176534) 53.1922 (+-0.154948) 8.00003 (+-0.000781588)
found 4.58 (+-0.000177376) 53.1924 (+-0.155033) 8.00007 (+-0.000782018)
found -4.06 (+-0.000188682) 46.5431 (+-0.144936) 7.00003 (+-0.000731087)
found 6.02 (+-0.000189671) 46.5433 (+-0.145024) 7.00006 (+-0.000731533)
found 8.9 (+-0.000189526) 46.5434 (+-0.145018) 7.00007 (+-0.000731501)
found -5.86 (+-0.000206174) 39.8947 (+-0.134375) 6.00011 (+-0.000677818)
found -1.18 (+-0.00020516) 39.8944 (+-0.134294) 6.00007 (+-0.000677405)
found -9.46 (+-0.000204316) 39.8942 (+-0.134226) 6.00004 (+-0.000677062)
found -8.02 (+-0.000203386) 39.894 (+-0.134153) 6.00001 (+-0.000676697)
found 1.7 (+-0.000204534) 39.8942 (+-0.13424) 6.00004 (+-0.000677133)
found 2.78 (+-0.000205405) 39.8945 (+-0.134312) 6.00008 (+-0.0006775)
found 4.22 (+-0.000205049) 39.8944 (+-0.134284) 6.00007 (+-0.000677357)
found -2.26 (+-0.000225054) 33.2455 (+-0.122615) 5.00007 (+-0.000618494)
found 3.5 (+-0.000225054) 33.2455 (+-0.122615) 5.00007 (+-0.000618494)
found -9.82 (+-0.000224781) 33.2452 (+-0.122583) 5.00004 (+-0.000618335)
found -3.34 (+-0.00022297) 33.2451 (+-0.122475) 5.00001 (+-0.00061779)
found -0.46 (+-0.000224266) 33.2452 (+-0.122558) 5.00004 (+-0.000618209)
found 6.38 (+-0.000225304) 33.2455 (+-0.122629) 5.00007 (+-0.000618566)
found 7.82 (+-0.000224038) 33.2452 (+-0.122543) 5.00003 (+-0.00061813)
found -0.0999996 (+-0.000252797) 26.5966 (+-0.109734) 4.00009 (+-0.000553521)
found 4.94 (+-0.000252557) 26.5965 (+-0.109721) 4.00008 (+-0.000553453)
found 5.3 (+-0.000251751) 26.5963 (+-0.109674) 4.00005 (+-0.000553219)
found 5.66 (+-0.000252386) 26.5965 (+-0.10971) 4.00007 (+-0.000553402)
found 6.74 (+-0.000251709) 26.5963 (+-0.109672) 4.00005 (+-0.000553209)
found -4.42 (+-0.000293473) 19.9477 (+-0.0951019) 3.00011 (+-0.000479714)
found 2.06 (+-0.000291628) 19.9474 (+-0.0950208) 3.00006 (+-0.000479305)
found 7.1 (+-0.000290609) 19.9472 (+-0.0949774) 3.00004 (+-0.000479086)
found 8.18 (+-0.000290285) 19.9472 (+-0.0949663) 3.00004 (+-0.00047903)
found -8.74 (+-0.000288572) 19.9471 (+-0.0948954) 3.00001 (+-0.000478672)
found 1.34 (+-0.000290549) 19.9473 (+-0.0949782) 3.00005 (+-0.00047909)
found 2.42 (+-0.000291628) 19.9474 (+-0.0950208) 3.00006 (+-0.000479305)
found -0.82 (+-0.000359567) 13.2985 (+-0.0776546) 2.00007 (+-0.000391706)
found -6.94 (+-0.000358889) 13.2985 (+-0.0776377) 2.00007 (+-0.000391621)
found -1.9 (+-0.000360496) 13.2986 (+-0.0776837) 2.00009 (+-0.000391853)
found 3.86 (+-0.000359567) 13.2985 (+-0.0776546) 2.00007 (+-0.000391706)
found 7.46 (+-0.000358239) 13.2983 (+-0.0776151) 2.00005 (+-0.000391507)
found -7.3 (+-0.000355143) 13.2981 (+-0.0775273) 2.00002 (+-0.000391064)
found -5.14 (+-0.000517129) 6.6498 (+-0.0550486) 1.00012 (+-0.000277677)
found 0.619996 (+-0.000509692) 6.6494 (+-0.054934) 1.00006 (+-0.000277099)
found -3.7 (+-0.000513718) 6.64953 (+-0.0549923) 1.00008 (+-0.000277393)
found -2.98 (+-0.000514767) 6.64962 (+-0.05501) 1.00009 (+-0.000277482)
found -9.1 (+-0.000511403) 6.6494 (+-0.0549558) 1.00006 (+-0.000277208)
found -7.66 (+-0.000510232) 6.64935 (+-0.0549384) 1.00005 (+-0.000277121)
found 8.54 (+-0.000512001) 6.64944 (+-0.0549657) 1.00007 (+-0.000277259)
found -8.38 (+-0.000511403) 6.6494 (+-0.0549558) 1.00006 (+-0.000277208)
found 0.980001 (+-0.00050625) 6.64918 (+-0.0548776) 1.00003 (+-0.000276814)

 
#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.