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 19.9471 3
created -9.46 66.4904 10
created -9.1 39.8942 6
created -8.74 6.64904 1
created -8.38 26.5962 4
created -8.02 53.1923 8
created -7.66 33.2452 5
created -7.3 13.2981 2
created -6.94 53.1923 8
created -6.58 6.64904 1
created -6.22 19.9471 3
created -5.86 53.1923 8
created -5.5 33.2452 5
created -5.14 59.8413 9
created -4.78 59.8413 9
created -4.42 59.8413 9
created -4.06 19.9471 3
created -3.7 39.8942 6
created -3.34 33.2452 5
created -2.98 66.4904 10
created -2.62 53.1923 8
created -2.26 66.4904 10
created -1.9 13.2981 2
created -1.54 13.2981 2
created -1.18 19.9471 3
created -0.82 13.2981 2
created -0.46 59.8413 9
created -0.1 19.9471 3
created 0.26 39.8942 6
created 0.62 66.4904 10
created 0.98 39.8942 6
created 1.34 13.2981 2
created 1.7 19.9471 3
created 2.06 53.1923 8
created 2.42 13.2981 2
created 2.78 66.4904 10
created 3.14 19.9471 3
created 3.5 66.4904 10
created 3.86 26.5962 4
created 4.22 39.8942 6
created 4.58 39.8942 6
created 4.94 26.5962 4
created 5.3 66.4904 10
created 5.66 26.5962 4
created 6.02 53.1923 8
created 6.38 46.5433 7
created 6.74 6.64904 1
created 7.1 19.9471 3
created 7.46 66.4904 10
created 7.82 39.8942 6
created 8.18 26.5962 4
created 8.54 26.5962 4
created 8.9 53.1923 8
created 9.26 59.8413 9
created 9.62 53.1923 8
the total number of created peaks = 55 with sigma = 0.06
the total number of found peaks = 55 with sigma = 0.0600004 (+-1.44977e-05)
fit chi^2 = 3.05478e-06
found -9.46 (+-0.000141744) 66.4903 (+-0.155168) 10.0001 (+-0.000782703)
found -2.98 (+-0.000142096) 66.4905 (+-0.155215) 10.0001 (+-0.000782935)
found -2.26 (+-0.00014175) 66.4904 (+-0.155171) 10.0001 (+-0.000782716)
found 0.62 (+-0.000142036) 66.4904 (+-0.155206) 10.0001 (+-0.000782893)
found 2.78 (+-0.000141317) 66.4901 (+-0.155114) 10 (+-0.000782427)
found 3.5 (+-0.000141565) 66.4902 (+-0.155145) 10 (+-0.000782584)
found 5.3 (+-0.000141677) 66.4903 (+-0.155159) 10.0001 (+-0.000782655)
found 7.46 (+-0.000141744) 66.4903 (+-0.155168) 10.0001 (+-0.000782703)
found -4.78 (+-0.000150287) 59.8417 (+-0.147311) 9.00012 (+-0.000743069)
found -4.42 (+-0.000149735) 59.8415 (+-0.147245) 9.00008 (+-0.000742736)
found 9.26 (+-0.000150146) 59.8416 (+-0.147294) 9.00011 (+-0.00074298)
found -5.14 (+-0.000149964) 59.8416 (+-0.147272) 9.00009 (+-0.00074287)
found -0.46 (+-0.000149038) 59.8411 (+-0.147163) 9.00003 (+-0.000742319)
found -2.62 (+-0.000159705) 53.1928 (+-0.13892) 8.00013 (+-0.000700744)
found 9.62 (+-0.000157923) 53.1927 (+-0.138751) 8.00011 (+-0.000699887)
found -8.02 (+-0.000158729) 53.1923 (+-0.138813) 8.00006 (+-0.000700202)
found -6.94 (+-0.000157777) 53.1921 (+-0.138717) 8.00002 (+-0.000699717)
found -5.86 (+-0.000158592) 53.1923 (+-0.138799) 8.00005 (+-0.000700131)
found 2.06 (+-0.000158173) 53.1922 (+-0.138756) 8.00003 (+-0.000699913)
found 6.02 (+-0.000158923) 53.1924 (+-0.138834) 8.00007 (+-0.000700309)
found 8.9 (+-0.000159084) 53.1925 (+-0.138852) 8.00009 (+-0.0007004)
found 6.38 (+-0.000169545) 46.5433 (+-0.129839) 7.00006 (+-0.000654937)
found -9.1 (+-0.000183498) 39.8944 (+-0.120239) 6.00007 (+-0.000606512)
found 0.979999 (+-0.000183802) 39.8945 (+-0.120261) 6.00008 (+-0.000606623)
found 7.82 (+-0.000184199) 39.8946 (+-0.120292) 6.00009 (+-0.000606778)
found -3.7 (+-0.000183474) 39.8943 (+-0.120231) 6.00005 (+-0.000606471)
found 0.260001 (+-0.000184022) 39.8945 (+-0.120278) 6.00009 (+-0.000606708)
found 4.22 (+-0.000183781) 39.8944 (+-0.120256) 6.00007 (+-0.000606597)
found 4.58 (+-0.000183781) 39.8944 (+-0.120256) 6.00007 (+-0.000606597)
found -7.66 (+-0.000201409) 33.2454 (+-0.109787) 5.00007 (+-0.000553787)
found -5.5 (+-0.000202592) 33.2457 (+-0.109868) 5.00011 (+-0.000554197)
found -3.34 (+-0.000202433) 33.2457 (+-0.109857) 5.00011 (+-0.000554141)
found 3.86 (+-0.000226829) 26.5967 (+-0.0982884) 4.00011 (+-0.000495788)
found 4.94 (+-0.000226829) 26.5967 (+-0.0982884) 4.00011 (+-0.000495788)
found 5.66 (+-0.000227155) 26.5968 (+-0.0983073) 4.00012 (+-0.000495883)
found 8.18 (+-0.000225831) 26.5964 (+-0.0982303) 4.00007 (+-0.000495494)
found 8.54 (+-0.000226152) 26.5965 (+-0.0982492) 4.00008 (+-0.00049559)
found -8.38 (+-0.000225148) 26.5964 (+-0.0981969) 4.00006 (+-0.000495326)
found -4.06 (+-0.000262572) 19.9476 (+-0.0851493) 3.0001 (+-0.000429511)
found -0.100001 (+-0.000262572) 19.9476 (+-0.0851493) 3.0001 (+-0.000429511)
found 3.14 (+-0.000263507) 19.9479 (+-0.0851918) 3.00013 (+-0.000429725)
found -9.82 (+-0.000261228) 19.9474 (+-0.0850873) 3.00007 (+-0.000429198)
found -6.22 (+-0.000260576) 19.9474 (+-0.0850667) 3.00006 (+-0.000429094)
found -1.18 (+-0.000259509) 19.9472 (+-0.0850175) 3.00003 (+-0.000428846)
found 1.7 (+-0.000261142) 19.9474 (+-0.0850885) 3.00007 (+-0.000429204)
found 7.1 (+-0.000260917) 19.9475 (+-0.0850827) 3.00007 (+-0.000429175)
found -1.9 (+-0.000321598) 13.2985 (+-0.0695282) 2.00008 (+-0.000350715)
found 1.34 (+-0.000321123) 13.2984 (+-0.0695107) 2.00006 (+-0.000350627)
found 2.42 (+-0.000323971) 13.2988 (+-0.0695978) 2.00012 (+-0.000351066)
found -7.3 (+-0.000322553) 13.2986 (+-0.0695538) 2.00009 (+-0.000350844)
found -1.54 (+-0.000319373) 13.2982 (+-0.0694593) 2.00003 (+-0.000350367)
found -0.819998 (+-0.000321947) 13.2985 (+-0.0695368) 2.00008 (+-0.000350758)
found -6.58 (+-0.000458956) 6.64949 (+-0.0492272) 1.00007 (+-0.000248312)
found 6.74 (+-0.000458471) 6.64944 (+-0.049219) 1.00007 (+-0.000248271)
found -8.74 (+-0.000458768) 6.64944 (+-0.0492229) 1.00007 (+-0.000248291)

 
#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.