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 26.5962 4
created -9.46 19.9471 3
created -9.1 13.2981 2
created -8.74 53.1923 8
created -8.38 59.8413 9
created -8.02 33.2452 5
created -7.66 46.5433 7
created -7.3 33.2452 5
created -6.94 53.1923 8
created -6.58 33.2452 5
created -6.22 26.5962 4
created -5.86 53.1923 8
created -5.5 33.2452 5
created -5.14 19.9471 3
created -4.78 6.64904 1
created -4.42 59.8413 9
created -4.06 6.64904 1
created -3.7 26.5962 4
created -3.34 33.2452 5
created -2.98 6.64904 1
created -2.62 66.4904 10
created -2.26 33.2452 5
created -1.9 46.5433 7
created -1.54 6.64904 1
created -1.18 6.64904 1
created -0.82 13.2981 2
created -0.46 33.2452 5
created -0.1 33.2452 5
created 0.26 59.8413 9
created 0.62 66.4904 10
created 0.98 53.1923 8
created 1.34 53.1923 8
created 1.7 66.4904 10
created 2.06 19.9471 3
created 2.42 59.8413 9
created 2.78 59.8413 9
created 3.14 33.2452 5
created 3.5 59.8413 9
created 3.86 66.4904 10
created 4.22 53.1923 8
created 4.58 19.9471 3
created 4.94 13.2981 2
created 5.3 66.4904 10
created 5.66 26.5962 4
created 6.02 13.2981 2
created 6.38 26.5962 4
created 6.74 6.64904 1
created 7.1 59.8413 9
created 7.46 59.8413 9
created 7.82 66.4904 10
created 8.18 19.9471 3
created 8.54 33.2452 5
created 8.9 26.5962 4
created 9.26 59.8413 9
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 (+-1.61934e-05)
fit chi^2 = 3.81078e-06
found -2.62 (+-0.000157857) 66.4902 (+-0.173253) 10 (+-0.000873924)
found 0.62 (+-0.000159037) 66.4907 (+-0.173405) 10.0001 (+-0.000874689)
found 1.7 (+-0.000158476) 66.4904 (+-0.173331) 10.0001 (+-0.000874317)
found 3.86 (+-0.000159037) 66.4907 (+-0.173405) 10.0001 (+-0.000874689)
found 5.3 (+-0.000157962) 66.4902 (+-0.173264) 10 (+-0.000873978)
found 7.82 (+-0.000158547) 66.4905 (+-0.173341) 10.0001 (+-0.000874366)
found 9.62 (+-0.000157623) 66.4908 (+-0.173243) 10.0001 (+-0.000873876)
found -8.38 (+-0.000167417) 59.8415 (+-0.164479) 9.00009 (+-0.000829667)
found 2.78 (+-0.000167496) 59.8416 (+-0.164489) 9.00009 (+-0.000829717)
found 7.46 (+-0.00016793) 59.8418 (+-0.164542) 9.00013 (+-0.000829986)
found -4.42 (+-0.000165834) 59.841 (+-0.164299) 9.00001 (+-0.000828758)
found 0.26 (+-0.000167569) 59.8416 (+-0.164498) 9.0001 (+-0.000829764)
found 2.42 (+-0.00016724) 59.8415 (+-0.164459) 9.00008 (+-0.000829568)
found 3.5 (+-0.000167569) 59.8416 (+-0.164498) 9.0001 (+-0.000829764)
found 7.1 (+-0.000166836) 59.8414 (+-0.164416) 9.00007 (+-0.000829348)
found 9.26 (+-0.000167451) 59.8416 (+-0.164484) 9.00009 (+-0.000829694)
found 0.98 (+-0.000178207) 53.1927 (+-0.155142) 8.00012 (+-0.00078257)
found 1.34 (+-0.000178207) 53.1927 (+-0.155142) 8.00012 (+-0.00078257)
found 4.22 (+-0.000177609) 53.1925 (+-0.155079) 8.00009 (+-0.000782249)
found -8.74 (+-0.00017734) 53.1924 (+-0.155051) 8.00007 (+-0.000782108)
found -6.94 (+-0.000177415) 53.1924 (+-0.155055) 8.00007 (+-0.00078213)
found -5.86 (+-0.000177285) 53.1923 (+-0.155041) 8.00006 (+-0.000782061)
found -7.66 (+-0.000189842) 46.5434 (+-0.145057) 7.00007 (+-0.0007317)
found -1.9 (+-0.000189021) 46.5432 (+-0.144985) 7.00004 (+-0.000731333)
found -8.02 (+-0.000226133) 33.2457 (+-0.122702) 5.00011 (+-0.000618935)
found -6.58 (+-0.000225475) 33.2455 (+-0.122656) 5.00008 (+-0.000618701)
found -5.5 (+-0.000225243) 33.2455 (+-0.12264) 5.00007 (+-0.000618623)
found -2.26 (+-0.000226255) 33.2457 (+-0.122711) 5.00011 (+-0.00061898)
found 3.14 (+-0.000226407) 33.2458 (+-0.122722) 5.00012 (+-0.000619035)
found -7.3 (+-0.000226003) 33.2456 (+-0.122692) 5.0001 (+-0.000618887)
found -3.34 (+-0.0002239) 33.2452 (+-0.12255) 5.00003 (+-0.000618168)
found -0.46 (+-0.000224491) 33.2453 (+-0.122588) 5.00005 (+-0.00061836)
found -0.0999995 (+-0.000225803) 33.2456 (+-0.122679) 5.00009 (+-0.000618818)
found 8.54 (+-0.000224581) 33.2453 (+-0.122593) 5.00005 (+-0.000618385)
found -6.22 (+-0.000252831) 26.5966 (+-0.109749) 4.00009 (+-0.000553596)
found 5.66 (+-0.000252259) 26.5965 (+-0.10972) 4.00008 (+-0.000553449)
found 8.9 (+-0.000252989) 26.5966 (+-0.109758) 4.00009 (+-0.000553643)
found -9.82 (+-0.000250877) 26.5961 (+-0.10963) 4.00002 (+-0.000552997)
found -3.7 (+-0.000250909) 26.5962 (+-0.109644) 4.00004 (+-0.000553066)
found 6.38 (+-0.000250056) 26.5961 (+-0.109597) 4.00002 (+-0.000552828)
found -9.46 (+-0.000290648) 19.9472 (+-0.0949901) 3.00004 (+-0.00047915)
found -5.14 (+-0.000290324) 19.9473 (+-0.0949791) 3.00004 (+-0.000479095)
found 2.06 (+-0.000294124) 19.9478 (+-0.0951426) 3.00013 (+-0.00047992)
found 4.58 (+-0.000291671) 19.9474 (+-0.0950359) 3.00007 (+-0.000479381)
found 8.18 (+-0.000293184) 19.9477 (+-0.0951007) 3.0001 (+-0.000479708)
found -9.1 (+-0.000359306) 13.2985 (+-0.0776572) 2.00007 (+-0.000391719)
found 4.94 (+-0.000359845) 13.2986 (+-0.0776746) 2.00009 (+-0.000391807)
found 6.02 (+-0.000358368) 13.2983 (+-0.0776275) 2.00005 (+-0.00039157)
found -0.819999 (+-0.000356748) 13.2983 (+-0.0775835) 2.00004 (+-0.000391348)
found -4.06 (+-0.000514047) 6.64958 (+-0.055005) 1.00009 (+-0.000277457)
found -2.98 (+-0.0005153) 6.64967 (+-0.0550253) 1.0001 (+-0.000277559)
found -1.54 (+-0.000509228) 6.64936 (+-0.0549323) 1.00005 (+-0.00027709)
found -4.78 (+-0.000513108) 6.64953 (+-0.0549907) 1.00008 (+-0.000277385)
found 6.74 (+-0.000514047) 6.64958 (+-0.055005) 1.00009 (+-0.000277457)
found -1.18 (+-0.000505182) 6.64913 (+-0.0548676) 1.00002 (+-0.000276764)

 
#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.