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 13.2981 2
created -9.1 39.8942 6
created -8.74 53.1923 8
created -8.38 39.8942 6
created -8.02 6.64904 1
created -7.66 39.8942 6
created -7.3 19.9471 3
created -6.94 6.64904 1
created -6.58 39.8942 6
created -6.22 39.8942 6
created -5.86 19.9471 3
created -5.5 26.5962 4
created -5.14 26.5962 4
created -4.78 53.1923 8
created -4.42 46.5433 7
created -4.06 53.1923 8
created -3.7 59.8413 9
created -3.34 13.2981 2
created -2.98 53.1923 8
created -2.62 13.2981 2
created -2.26 6.64904 1
created -1.9 13.2981 2
created -1.54 13.2981 2
created -1.18 13.2981 2
created -0.82 26.5962 4
created -0.46 39.8942 6
created -0.1 66.4904 10
created 0.26 66.4904 10
created 0.62 33.2452 5
created 0.98 6.64904 1
created 1.34 6.64904 1
created 1.7 59.8413 9
created 2.06 46.5433 7
created 2.42 53.1923 8
created 2.78 13.2981 2
created 3.14 53.1923 8
created 3.5 53.1923 8
created 3.86 6.64904 1
created 4.22 39.8942 6
created 4.58 39.8942 6
created 4.94 59.8413 9
created 5.3 53.1923 8
created 5.66 46.5433 7
created 6.02 13.2981 2
created 6.38 13.2981 2
created 6.74 13.2981 2
created 7.1 53.1923 8
created 7.46 46.5433 7
created 7.82 66.4904 10
created 8.18 19.9471 3
created 8.54 33.2452 5
created 8.9 46.5433 7
created 9.26 13.2981 2
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 (+-1.32462e-05)
fit chi^2 = 2.298e-06
found -0.0999998 (+-0.000123425) 66.4906 (+-0.134647) 10.0001 (+-0.000679189)
found 0.26 (+-0.000123352) 66.4906 (+-0.134637) 10.0001 (+-0.00067914)
found 7.82 (+-0.000123004) 66.4904 (+-0.134591) 10.0001 (+-0.000678907)
found -3.7 (+-0.000129677) 59.8414 (+-0.127688) 9.00007 (+-0.000644087)
found 1.7 (+-0.000129431) 59.8413 (+-0.127661) 9.00005 (+-0.000643949)
found 4.94 (+-0.000130088) 59.8416 (+-0.127736) 9.00009 (+-0.000644325)
found 3.5 (+-0.000137444) 53.1923 (+-0.120377) 8.00006 (+-0.000607209)
found 5.3 (+-0.00013825) 53.1926 (+-0.12046) 8.00011 (+-0.000607626)
found -9.82 (+-0.000137304) 53.192 (+-0.120349) 8.00001 (+-0.000607067)
found -8.74 (+-0.000137949) 53.1925 (+-0.120427) 8.00008 (+-0.000607458)
found -4.78 (+-0.000137839) 53.1924 (+-0.120415) 8.00007 (+-0.0006074)
found -4.06 (+-0.00013825) 53.1927 (+-0.12046) 8.00011 (+-0.000607626)
found -2.98 (+-0.000137044) 53.1921 (+-0.120333) 8.00003 (+-0.000606983)
found 2.42 (+-0.000137574) 53.1923 (+-0.120388) 8.00006 (+-0.000607265)
found 3.14 (+-0.000137646) 53.1924 (+-0.120397) 8.00007 (+-0.000607306)
found 7.1 (+-0.000137574) 53.1923 (+-0.120388) 8.00006 (+-0.000607265)
found -4.42 (+-0.000147966) 46.5437 (+-0.112697) 7.00011 (+-0.000568466)
found 2.06 (+-0.000148042) 46.5437 (+-0.112704) 7.00011 (+-0.000568504)
found 5.66 (+-0.00014728) 46.5434 (+-0.112633) 7.00007 (+-0.000568144)
found 7.46 (+-0.000148113) 46.5437 (+-0.112711) 7.00012 (+-0.00056854)
found 8.9 (+-0.000147011) 46.5433 (+-0.112607) 7.00005 (+-0.000568012)
found -8.38 (+-0.000158989) 39.8944 (+-0.104273) 6.00006 (+-0.000525974)
found -9.1 (+-0.000159252) 39.8944 (+-0.104292) 6.00007 (+-0.00052607)
found -7.66 (+-0.000158404) 39.8941 (+-0.104224) 6.00003 (+-0.000525728)
found -6.58 (+-0.000158795) 39.8943 (+-0.104256) 6.00005 (+-0.00052589)
found -6.22 (+-0.000159247) 39.8944 (+-0.10429) 6.00006 (+-0.000526059)
found -0.459999 (+-0.000159762) 39.8946 (+-0.104333) 6.00009 (+-0.000526278)
found 4.22 (+-0.000158795) 39.8943 (+-0.104256) 6.00005 (+-0.00052589)
found 4.58 (+-0.000159928) 39.8946 (+-0.104346) 6.0001 (+-0.000526344)
found 9.62 (+-0.000157515) 39.8943 (+-0.104167) 6.00005 (+-0.000525439)
found 0.619999 (+-0.000174571) 33.2455 (+-0.0952168) 5.00007 (+-0.000480293)
found 8.54 (+-0.000174803) 33.2454 (+-0.0952279) 5.00007 (+-0.00048035)
found -5.14 (+-0.000196149) 26.5965 (+-0.0852147) 4.00008 (+-0.000429841)
found -5.5 (+-0.000195306) 26.5963 (+-0.0851666) 4.00005 (+-0.000429598)
found -0.819999 (+-0.000195381) 26.5963 (+-0.085172) 4.00005 (+-0.000429625)
found -7.3 (+-0.000225656) 19.9473 (+-0.073765) 3.00005 (+-0.000372086)
found -5.86 (+-0.000226774) 19.9474 (+-0.0738099) 3.00007 (+-0.000372313)
found 8.18 (+-0.000227671) 19.9477 (+-0.0738502) 3.0001 (+-0.000372516)
found -3.34 (+-0.000280785) 13.2987 (+-0.0603579) 2.00011 (+-0.000304458)
found -9.46 (+-0.000280058) 13.2986 (+-0.0603352) 2.00009 (+-0.000304344)
found -2.62 (+-0.000277813) 13.2984 (+-0.0602719) 2.00006 (+-0.000304024)
found 2.78 (+-0.000280564) 13.2987 (+-0.0603509) 2.00011 (+-0.000304423)
found 6.02 (+-0.00027828) 13.2984 (+-0.060283) 2.00006 (+-0.00030408)
found 9.26 (+-0.000279819) 13.2986 (+-0.0603277) 2.00009 (+-0.000304306)
found -1.54 (+-0.000276512) 13.2982 (+-0.0602303) 2.00003 (+-0.000303814)
found -1.18 (+-0.000277396) 13.2983 (+-0.0602559) 2.00004 (+-0.000303943)
found 6.38 (+-0.000276511) 13.2982 (+-0.0602303) 2.00003 (+-0.000303814)
found 6.74 (+-0.000278516) 13.2984 (+-0.0602905) 2.00007 (+-0.000304118)
found -1.9 (+-0.000275823) 13.2981 (+-0.0602117) 2.00002 (+-0.000303721)
found 3.86 (+-0.000399937) 6.64962 (+-0.0427255) 1.00009 (+-0.000215517)
found -8.02 (+-0.00039904) 6.64953 (+-0.0427107) 1.00008 (+-0.000215442)
found 0.979998 (+-0.00039447) 6.64927 (+-0.0426414) 1.00004 (+-0.000215092)
found -6.94 (+-0.000397182) 6.6494 (+-0.0426815) 1.00006 (+-0.000215294)
found 1.34 (+-0.000396233) 6.64945 (+-0.0426712) 1.00007 (+-0.000215243)
found -2.26 (+-0.000393561) 6.64917 (+-0.0426254) 1.00003 (+-0.000215012)

 
#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.