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 13.2981 2
created -9.46 13.2981 2
created -9.1 26.5962 4
created -8.74 33.2452 5
created -8.38 53.1923 8
created -8.02 6.64904 1
created -7.66 46.5433 7
created -7.3 53.1923 8
created -6.94 33.2452 5
created -6.58 33.2452 5
created -6.22 6.64904 1
created -5.86 53.1923 8
created -5.5 33.2452 5
created -5.14 33.2452 5
created -4.78 66.4904 10
created -4.42 33.2452 5
created -4.06 59.8413 9
created -3.7 19.9471 3
created -3.34 13.2981 2
created -2.98 13.2981 2
created -2.62 19.9471 3
created -2.26 53.1923 8
created -1.9 39.8942 6
created -1.54 46.5433 7
created -1.18 26.5962 4
created -0.82 13.2981 2
created -0.46 13.2981 2
created -0.1 19.9471 3
created 0.26 13.2981 2
created 0.62 59.8413 9
created 0.98 59.8413 9
created 1.34 13.2981 2
created 1.7 19.9471 3
created 2.06 66.4904 10
created 2.42 46.5433 7
created 2.78 33.2452 5
created 3.14 66.4904 10
created 3.5 46.5433 7
created 3.86 59.8413 9
created 4.22 6.64904 1
created 4.58 6.64904 1
created 4.94 26.5962 4
created 5.3 39.8942 6
created 5.66 33.2452 5
created 6.02 66.4904 10
created 6.38 19.9471 3
created 6.74 26.5962 4
created 7.1 66.4904 10
created 7.46 13.2981 2
created 7.82 66.4904 10
created 8.18 59.8413 9
created 8.54 46.5433 7
created 8.9 39.8942 6
created 9.26 33.2452 5
created 9.62 59.8413 9
the total number of created peaks = 55 with sigma = 0.06
the total number of found peaks = 55 with sigma = 0.0600004 (+-1.58457e-05)
fit chi^2 = 3.43037e-06
found -4.78 (+-0.000150336) 66.4904 (+-0.164447) 10.0001 (+-0.000829508)
found 2.06 (+-0.000150285) 66.4904 (+-0.164442) 10.0001 (+-0.00082948)
found 3.14 (+-0.000150505) 66.4905 (+-0.16447) 10.0001 (+-0.000829622)
found 6.02 (+-0.000150116) 66.4903 (+-0.164419) 10.0001 (+-0.000829366)
found 7.1 (+-0.00014987) 66.4902 (+-0.164388) 10 (+-0.000829209)
found 7.82 (+-0.000150279) 66.4904 (+-0.164443) 10.0001 (+-0.000829487)
found 0.98 (+-0.000158511) 59.8414 (+-0.156017) 9.00007 (+-0.000786983)
found 8.18 (+-0.000159172) 59.8417 (+-0.156094) 9.00011 (+-0.000787373)
found -4.06 (+-0.000158334) 59.8413 (+-0.155993) 9.00005 (+-0.000786863)
found 0.62 (+-0.000158511) 59.8414 (+-0.156017) 9.00007 (+-0.000786983)
found 3.86 (+-0.000158137) 59.8413 (+-0.155974) 9.00005 (+-0.000786768)
found 9.62 (+-0.00015737) 59.8415 (+-0.155901) 9.00009 (+-0.000786396)
found -8.38 (+-0.000167636) 53.1922 (+-0.147043) 8.00004 (+-0.000741717)
found -7.3 (+-0.000168533) 53.1925 (+-0.147135) 8.00008 (+-0.000742179)
found -5.86 (+-0.000167636) 53.1922 (+-0.147043) 8.00004 (+-0.000741717)
found -2.26 (+-0.000168167) 53.1923 (+-0.147096) 8.00006 (+-0.000741984)
found 2.42 (+-0.000180628) 46.5436 (+-0.137677) 7.0001 (+-0.000694472)
found 3.5 (+-0.000181056) 46.5438 (+-0.137718) 7.00013 (+-0.000694681)
found 8.54 (+-0.000180665) 46.5436 (+-0.13768) 7.0001 (+-0.000694487)
found -7.66 (+-0.000179666) 46.5433 (+-0.13759) 7.00006 (+-0.000694033)
found -1.54 (+-0.000180101) 46.5434 (+-0.137626) 7.00007 (+-0.000694212)
found -1.9 (+-0.000195418) 39.8946 (+-0.12749) 6.0001 (+-0.000643087)
found 5.3 (+-0.000194612) 39.8944 (+-0.127423) 6.00006 (+-0.000642748)
found 8.9 (+-0.000195036) 39.8945 (+-0.127458) 6.00008 (+-0.000642926)
found -6.94 (+-0.000214113) 33.2455 (+-0.116385) 5.00009 (+-0.000587073)
found -5.5 (+-0.000214113) 33.2455 (+-0.116385) 5.00009 (+-0.000587073)
found -4.42 (+-0.000214926) 33.2458 (+-0.116444) 5.00013 (+-0.000587368)
found -8.74 (+-0.000213925) 33.2455 (+-0.116373) 5.00008 (+-0.000587008)
found -6.58 (+-0.000212615) 33.2452 (+-0.116285) 5.00004 (+-0.000586567)
found -5.14 (+-0.000214351) 33.2456 (+-0.116403) 5.0001 (+-0.000587162)
found 2.78 (+-0.000214665) 33.2457 (+-0.116425) 5.00011 (+-0.000587273)
found 5.66 (+-0.000214517) 33.2457 (+-0.116415) 5.00011 (+-0.00058722)
found 9.26 (+-0.000214401) 33.2456 (+-0.116406) 5.0001 (+-0.000587177)
found -1.18 (+-0.000238891) 26.5964 (+-0.104072) 4.00006 (+-0.000524963)
found -9.1 (+-0.000238517) 26.5963 (+-0.104051) 4.00005 (+-0.000524853)
found 4.94 (+-0.000238252) 26.5963 (+-0.104039) 4.00005 (+-0.000524793)
found 6.74 (+-0.000239671) 26.5966 (+-0.104117) 4.00009 (+-0.000525187)
found -3.7 (+-0.000276919) 19.9475 (+-0.0901765) 3.00007 (+-0.000454869)
found 6.38 (+-0.000277871) 19.9476 (+-0.0902166) 3.00009 (+-0.000455072)
found -2.62 (+-0.000276731) 19.9474 (+-0.0901677) 3.00007 (+-0.000454825)
found -0.1 (+-0.000275) 19.9472 (+-0.0900925) 3.00003 (+-0.000454446)
found 1.7 (+-0.000277094) 19.9475 (+-0.0901847) 3.00008 (+-0.000454911)
found 1.34 (+-0.000341166) 13.2985 (+-0.0736877) 2.00008 (+-0.000371697)
found 7.46 (+-0.000343832) 13.2989 (+-0.0737689) 2.00014 (+-0.000372106)
found -9.46 (+-0.000338919) 13.2983 (+-0.0736198) 2.00004 (+-0.000371354)
found -3.34 (+-0.000338438) 13.2982 (+-0.0736056) 2.00003 (+-0.000371282)
found -2.98 (+-0.000338438) 13.2982 (+-0.0736056) 2.00003 (+-0.000371282)
found -0.820001 (+-0.000338919) 13.2983 (+-0.0736198) 2.00004 (+-0.000371354)
found -0.46 (+-0.000338438) 13.2982 (+-0.0736056) 2.00003 (+-0.000371282)
found 0.260002 (+-0.000341166) 13.2985 (+-0.0736877) 2.00008 (+-0.000371697)
found -9.82 (+-0.000336992) 13.2981 (+-0.0735595) 2.00001 (+-0.00037105)
found -8.02 (+-0.000489217) 6.64967 (+-0.0522109) 1.0001 (+-0.000263363)
found 4.22 (+-0.000484112) 6.64945 (+-0.0521351) 1.00007 (+-0.00026298)
found -6.22 (+-0.000487988) 6.64958 (+-0.052191) 1.00009 (+-0.000263263)
found 4.58 (+-0.000481238) 6.64922 (+-0.052087) 1.00003 (+-0.000262738)

 
#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.