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 59.8413 9
created -9.1 39.8942 6
created -8.74 59.8413 9
created -8.38 66.4904 10
created -8.02 26.5962 4
created -7.66 53.1923 8
created -7.3 13.2981 2
created -6.94 39.8942 6
created -6.58 39.8942 6
created -6.22 66.4904 10
created -5.86 26.5962 4
created -5.5 19.9471 3
created -5.14 46.5433 7
created -4.78 6.64904 1
created -4.42 39.8942 6
created -4.06 13.2981 2
created -3.7 39.8942 6
created -3.34 26.5962 4
created -2.98 39.8942 6
created -2.62 19.9471 3
created -2.26 6.64904 1
created -1.9 26.5962 4
created -1.54 46.5433 7
created -1.18 13.2981 2
created -0.82 59.8413 9
created -0.46 59.8413 9
created -0.1 33.2452 5
created 0.26 13.2981 2
created 0.62 33.2452 5
created 0.98 13.2981 2
created 1.34 33.2452 5
created 1.7 46.5433 7
created 2.06 26.5962 4
created 2.42 33.2452 5
created 2.78 59.8413 9
created 3.14 33.2452 5
created 3.5 6.64904 1
created 3.86 33.2452 5
created 4.22 26.5962 4
created 4.58 59.8413 9
created 4.94 19.9471 3
created 5.3 19.9471 3
created 5.66 53.1923 8
created 6.02 19.9471 3
created 6.38 66.4904 10
created 6.74 39.8942 6
created 7.1 33.2452 5
created 7.46 26.5962 4
created 7.82 59.8413 9
created 8.18 13.2981 2
created 8.54 59.8413 9
created 8.9 59.8413 9
created 9.26 66.4904 10
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 (+-1.55138e-05)
fit chi^2 = 3.42898e-06
found -8.38 (+-0.000150514) 66.4905 (+-0.164443) 10.0001 (+-0.000829485)
found -6.22 (+-0.000150293) 66.4904 (+-0.164413) 10.0001 (+-0.000829333)
found 6.38 (+-0.000150175) 66.4903 (+-0.164398) 10.0001 (+-0.000829257)
found 9.26 (+-0.000150928) 66.4907 (+-0.164498) 10.0001 (+-0.000829763)
found -9.46 (+-0.000158908) 59.8416 (+-0.156034) 9.00009 (+-0.000787068)
found -0.46 (+-0.000158884) 59.8416 (+-0.156031) 9.00009 (+-0.000787056)
found 8.9 (+-0.000159296) 59.8418 (+-0.156082) 9.00013 (+-0.000787311)
found 9.62 (+-0.000157739) 59.8418 (+-0.15592) 9.00013 (+-0.000786492)
found -8.74 (+-0.000159051) 59.8416 (+-0.156052) 9.00011 (+-0.000787159)
found -0.82 (+-0.000158479) 59.8414 (+-0.155985) 9.00007 (+-0.000786824)
found 2.78 (+-0.000158543) 59.8414 (+-0.15599) 9.00007 (+-0.000786845)
found 4.58 (+-0.000158192) 59.8412 (+-0.155949) 9.00005 (+-0.000786637)
found 7.82 (+-0.000158031) 59.8412 (+-0.155931) 9.00004 (+-0.000786547)
found 8.54 (+-0.000158479) 59.8414 (+-0.155985) 9.00007 (+-0.000786824)
found -9.82 (+-0.000168544) 53.1923 (+-0.147099) 8.00006 (+-0.000741996)
found -7.66 (+-0.000167725) 53.1922 (+-0.147024) 8.00004 (+-0.000741619)
found 5.66 (+-0.000167759) 53.1922 (+-0.147027) 8.00004 (+-0.000741633)
found -5.14 (+-0.000179005) 46.5431 (+-0.137502) 7.00003 (+-0.00069359)
found -1.54 (+-0.000179442) 46.5432 (+-0.13754) 7.00004 (+-0.000693783)
found 1.7 (+-0.000179943) 46.5433 (+-0.137586) 7.00006 (+-0.000694013)
found -9.1 (+-0.000195706) 39.8948 (+-0.127492) 6.00012 (+-0.000643099)
found 6.74 (+-0.000195315) 39.8946 (+-0.12746) 6.0001 (+-0.000642934)
found -6.94 (+-0.000194295) 39.8943 (+-0.127376) 6.00005 (+-0.000642513)
found -6.58 (+-0.000195456) 39.8947 (+-0.127471) 6.00011 (+-0.000642993)
found -4.42 (+-0.000193269) 39.8941 (+-0.127296) 6.00002 (+-0.000642107)
found -3.7 (+-0.000193999) 39.8942 (+-0.127352) 6.00004 (+-0.000642389)
found -2.98 (+-0.000194229) 39.8943 (+-0.127369) 6.00005 (+-0.000642478)
found -0.100001 (+-0.000213512) 33.2455 (+-0.116326) 5.00007 (+-0.000586772)
found 3.14 (+-0.000213132) 33.2454 (+-0.116302) 5.00007 (+-0.000586654)
found 0.62 (+-0.000212278) 33.2451 (+-0.11624) 5.00003 (+-0.000586338)
found 1.34 (+-0.000213256) 33.2454 (+-0.116307) 5.00006 (+-0.000586677)
found 2.42 (+-0.000214005) 33.2455 (+-0.116358) 5.00009 (+-0.000586935)
found 3.86 (+-0.000212388) 33.2452 (+-0.116249) 5.00003 (+-0.000586384)
found 7.1 (+-0.000213601) 33.2454 (+-0.116329) 5.00007 (+-0.000586787)
found -8.02 (+-0.000240666) 26.5968 (+-0.104155) 4.00012 (+-0.000525378)
found -5.86 (+-0.000239622) 26.5966 (+-0.104096) 4.00009 (+-0.000525081)
found -3.34 (+-0.00023969) 26.5965 (+-0.104097) 4.00008 (+-0.000525088)
found 2.06 (+-0.000239669) 26.5965 (+-0.104096) 4.00008 (+-0.000525083)
found 4.22 (+-0.000239981) 26.5966 (+-0.104115) 4.00009 (+-0.000525177)
found 7.46 (+-0.000239981) 26.5966 (+-0.104115) 4.00009 (+-0.000525177)
found -1.9 (+-0.00023838) 26.5963 (+-0.104028) 4.00005 (+-0.000524739)
found -5.5 (+-0.000277241) 19.9475 (+-0.0901719) 3.00007 (+-0.000454846)
found -2.62 (+-0.000275647) 19.9473 (+-0.0901068) 3.00005 (+-0.000454518)
found 4.94 (+-0.000277293) 19.9475 (+-0.0901756) 3.00008 (+-0.000454865)
found 6.02 (+-0.000278808) 19.9478 (+-0.0902419) 3.00012 (+-0.000455199)
found 5.3 (+-0.000277103) 19.9475 (+-0.0901669) 3.00007 (+-0.000454821)
found 8.18 (+-0.000343261) 13.2988 (+-0.073738) 2.00012 (+-0.00037195)
found -7.3 (+-0.000342102) 13.2986 (+-0.0737018) 2.00009 (+-0.000371767)
found -4.06 (+-0.000341487) 13.2985 (+-0.0736827) 2.00008 (+-0.000371671)
found -1.18 (+-0.000342695) 13.2987 (+-0.0737203) 2.00011 (+-0.000371861)
found 0.26 (+-0.000340765) 13.2984 (+-0.0736607) 2.00007 (+-0.00037156)
found 0.98 (+-0.000340765) 13.2984 (+-0.0736607) 2.00007 (+-0.00037156)
found -4.78 (+-0.000488018) 6.64958 (+-0.0521822) 1.00009 (+-0.000263218)
found 3.5 (+-0.000486154) 6.64944 (+-0.052152) 1.00007 (+-0.000263065)
found -2.26 (+-0.000483805) 6.64931 (+-0.052115) 1.00005 (+-0.000262879)

 
#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.