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 66.4904 10
created -9.46 66.4904 10
created -9.1 46.5433 7
created -8.74 13.2981 2
created -8.38 59.8413 9
created -8.02 66.4904 10
created -7.66 46.5433 7
created -7.3 39.8942 6
created -6.94 53.1923 8
created -6.58 33.2452 5
created -6.22 13.2981 2
created -5.86 6.64904 1
created -5.5 66.4904 10
created -5.14 13.2981 2
created -4.78 13.2981 2
created -4.42 13.2981 2
created -4.06 39.8942 6
created -3.7 19.9471 3
created -3.34 46.5433 7
created -2.98 26.5962 4
created -2.62 6.64904 1
created -2.26 59.8413 9
created -1.9 13.2981 2
created -1.54 26.5962 4
created -1.18 59.8413 9
created -0.82 26.5962 4
created -0.46 66.4904 10
created -0.1 13.2981 2
created 0.26 66.4904 10
created 0.62 53.1923 8
created 0.98 39.8942 6
created 1.34 39.8942 6
created 1.7 13.2981 2
created 2.06 39.8942 6
created 2.42 46.5433 7
created 2.78 39.8942 6
created 3.14 66.4904 10
created 3.5 59.8413 9
created 3.86 66.4904 10
created 4.22 33.2452 5
created 4.58 59.8413 9
created 4.94 6.64904 1
created 5.3 66.4904 10
created 5.66 13.2981 2
created 6.02 66.4904 10
created 6.38 39.8942 6
created 6.74 19.9471 3
created 7.1 59.8413 9
created 7.46 39.8942 6
created 7.82 39.8942 6
created 8.18 46.5433 7
created 8.54 46.5433 7
created 8.9 6.64904 1
created 9.26 19.9471 3
created 9.62 39.8942 6
the total number of created peaks = 55 with sigma = 0.06
the total number of found peaks = 55 with sigma = 0.0600004 (+-1.24323e-05)
fit chi^2 = 2.30828e-06
found -9.82 (+-0.000123626) 66.4904 (+-0.134927) 10.0001 (+-0.000680598)
found -9.46 (+-0.000123767) 66.4907 (+-0.134957) 10.0001 (+-0.00068075)
found -8.02 (+-0.000123715) 66.4906 (+-0.134949) 10.0001 (+-0.000680714)
found -5.5 (+-0.000122561) 66.49 (+-0.134802) 10 (+-0.000679969)
found -0.46 (+-0.000122939) 66.4902 (+-0.134848) 10 (+-0.000680202)
found 0.26 (+-0.000123219) 66.4904 (+-0.134885) 10.0001 (+-0.000680391)
found 3.14 (+-0.000123649) 66.4906 (+-0.134941) 10.0001 (+-0.000680669)
found 3.86 (+-0.000123576) 66.4905 (+-0.134931) 10.0001 (+-0.00068062)
found 5.3 (+-0.000122561) 66.4901 (+-0.134802) 10 (+-0.000679969)
found 6.02 (+-0.000123094) 66.4903 (+-0.134868) 10.0001 (+-0.000680305)
found 3.5 (+-0.000130754) 59.8418 (+-0.128068) 9.00013 (+-0.000646)
found -8.38 (+-0.000130084) 59.8415 (+-0.127988) 9.00008 (+-0.0006456)
found -2.26 (+-0.000129244) 59.8411 (+-0.12789) 9.00002 (+-0.000645104)
found -1.18 (+-0.000129898) 59.8413 (+-0.127963) 9.00005 (+-0.000645472)
found 4.58 (+-0.00012957) 59.8412 (+-0.127928) 9.00004 (+-0.000645294)
found 7.1 (+-0.000129962) 59.8413 (+-0.127971) 9.00006 (+-0.000645513)
found 0.62 (+-0.000138541) 53.1927 (+-0.120727) 8.00011 (+-0.000608975)
found -6.94 (+-0.000138168) 53.1924 (+-0.120686) 8.00007 (+-0.000608766)
found -9.1 (+-0.000147754) 46.5435 (+-0.112899) 7.00008 (+-0.000569487)
found -7.66 (+-0.00014827) 46.5437 (+-0.112946) 7.00011 (+-0.000569725)
found -3.34 (+-0.000147391) 46.5433 (+-0.112862) 7.00005 (+-0.0005693)
found 2.42 (+-0.000147951) 46.5435 (+-0.112915) 7.00008 (+-0.000569566)
found 8.18 (+-0.000148041) 46.5435 (+-0.112923) 7.00009 (+-0.00056961)
found 8.54 (+-0.000147299) 46.5433 (+-0.112857) 7.00005 (+-0.000569276)
found 0.98 (+-0.000160198) 39.8946 (+-0.104572) 6.00009 (+-0.000527482)
found 6.38 (+-0.000159964) 39.8945 (+-0.104554) 6.00009 (+-0.000527392)
found 7.46 (+-0.000160285) 39.8946 (+-0.104579) 6.0001 (+-0.00052752)
found -7.3 (+-0.000160301) 39.8946 (+-0.10458) 6.0001 (+-0.000527525)
found -4.06 (+-0.000159018) 39.8942 (+-0.104476) 6.00003 (+-0.000526998)
found 1.34 (+-0.000159412) 39.8943 (+-0.104508) 6.00005 (+-0.000527161)
found 2.06 (+-0.000159515) 39.8944 (+-0.104517) 6.00006 (+-0.000527205)
found 2.78 (+-0.00016047) 39.8947 (+-0.104595) 6.00011 (+-0.000527599)
found 7.82 (+-0.000160104) 39.8945 (+-0.104564) 6.00009 (+-0.000527441)
found 9.62 (+-0.000158051) 39.8943 (+-0.104414) 6.00006 (+-0.000526686)
found -6.58 (+-0.000175079) 33.2454 (+-0.0954341) 5.00007 (+-0.00048139)
found 4.22 (+-0.000176304) 33.2458 (+-0.0955192) 5.00013 (+-0.000481819)
found -2.98 (+-0.000195583) 26.5963 (+-0.0853517) 4.00005 (+-0.000430532)
found -0.82 (+-0.000197583) 26.5968 (+-0.0854629) 4.00013 (+-0.000431093)
found -1.54 (+-0.000196216) 26.5965 (+-0.0853859) 4.00007 (+-0.000430705)
found -3.7 (+-0.000227918) 19.9476 (+-0.0740027) 3.00009 (+-0.000373285)
found 6.74 (+-0.000228246) 19.9477 (+-0.0740177) 3.0001 (+-0.000373361)
found 9.26 (+-0.000226159) 19.9473 (+-0.0739297) 3.00005 (+-0.000372917)
found -5.14 (+-0.000279555) 13.2985 (+-0.0604387) 2.00008 (+-0.000304865)
found -1.9 (+-0.000280263) 13.2986 (+-0.0604578) 2.00009 (+-0.000304962)
found -0.1 (+-0.000282046) 13.2989 (+-0.0605128) 2.00014 (+-0.000305239)
found 5.66 (+-0.000282046) 13.2989 (+-0.0605128) 2.00013 (+-0.000305239)
found -8.74 (+-0.00028117) 13.2987 (+-0.0604851) 2.00011 (+-0.0003051)
found 1.7 (+-0.000280179) 13.2985 (+-0.0604543) 2.00008 (+-0.000304944)
found -6.22 (+-0.000277651) 13.2983 (+-0.0603818) 2.00004 (+-0.000304579)
found -4.78 (+-0.000277129) 13.2982 (+-0.0603648) 2.00003 (+-0.000304493)
found -4.42 (+-0.000278642) 13.2983 (+-0.0604095) 2.00005 (+-0.000304718)
found 4.94 (+-0.000402893) 6.64985 (+-0.0428553) 1.00013 (+-0.000216171)
found 8.9 (+-0.000398535) 6.64944 (+-0.0427845) 1.00007 (+-0.000215814)
found -2.62 (+-0.000400073) 6.64958 (+-0.0428094) 1.00009 (+-0.00021594)
found -5.86 (+-0.000398778) 6.64954 (+-0.0427909) 1.00008 (+-0.000215846)

 
#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.