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 6.64904 1
created -9.1 33.2452 5
created -8.74 66.4904 10
created -8.38 59.8413 9
created -8.02 26.5962 4
created -7.66 53.1923 8
created -7.3 39.8942 6
created -6.94 19.9471 3
created -6.58 53.1923 8
created -6.22 19.9471 3
created -5.86 53.1923 8
created -5.5 33.2452 5
created -5.14 53.1923 8
created -4.78 39.8942 6
created -4.42 46.5433 7
created -4.06 46.5433 7
created -3.7 13.2981 2
created -3.34 33.2452 5
created -2.98 39.8942 6
created -2.62 26.5962 4
created -2.26 6.64904 1
created -1.9 6.64904 1
created -1.54 46.5433 7
created -1.18 13.2981 2
created -0.82 46.5433 7
created -0.46 46.5433 7
created -0.1 6.64904 1
created 0.26 33.2452 5
created 0.62 6.64904 1
created 0.98 66.4904 10
created 1.34 13.2981 2
created 1.7 6.64904 1
created 2.06 53.1923 8
created 2.42 19.9471 3
created 2.78 26.5962 4
created 3.14 66.4904 10
created 3.5 39.8942 6
created 3.86 13.2981 2
created 4.22 53.1923 8
created 4.58 26.5962 4
created 4.94 33.2452 5
created 5.3 6.64904 1
created 5.66 46.5433 7
created 6.02 46.5433 7
created 6.38 46.5433 7
created 6.74 53.1923 8
created 7.1 33.2452 5
created 7.46 6.64904 1
created 7.82 59.8413 9
created 8.18 13.2981 2
created 8.54 46.5433 7
created 8.9 6.64904 1
created 9.26 46.5433 7
created 9.62 26.5962 4
the total number of created peaks = 55 with sigma = 0.06
the total number of found peaks = 55 with sigma = 0.0600004 (+-1.0997e-05)
fit chi^2 = 1.55199e-06
found -8.74 (+-0.000101329) 66.4905 (+-0.11064) 10.0001 (+-0.000558091)
found 0.98 (+-0.000100497) 66.49 (+-0.110534) 10 (+-0.000557557)
found 3.14 (+-0.000101112) 66.4904 (+-0.110611) 10.0001 (+-0.000557944)
found -8.38 (+-0.000106862) 59.8415 (+-0.104969) 9.00009 (+-0.000529486)
found 7.82 (+-0.000105977) 59.841 (+-0.104866) 9.00002 (+-0.000528969)
found -7.66 (+-0.000113211) 53.1924 (+-0.0989507) 8.00007 (+-0.000499128)
found -6.58 (+-0.000112862) 53.1922 (+-0.0989139) 8.00004 (+-0.000498943)
found -5.86 (+-0.000113041) 53.1923 (+-0.0989327) 8.00005 (+-0.000499038)
found -5.14 (+-0.000113294) 53.1924 (+-0.0989594) 8.00007 (+-0.000499172)
found 2.06 (+-0.000112578) 53.1921 (+-0.0988862) 8.00002 (+-0.000498803)
found 4.22 (+-0.000112839) 53.1922 (+-0.098912) 8.00004 (+-0.000498933)
found 6.74 (+-0.00011336) 53.1925 (+-0.0989666) 8.00008 (+-0.000499209)
found -4.42 (+-0.00012139) 46.5435 (+-0.0925943) 7.00009 (+-0.000467065)
found -4.06 (+-0.000120969) 46.5433 (+-0.0925557) 7.00006 (+-0.00046687)
found -1.54 (+-0.000120294) 46.5431 (+-0.0924943) 7.00002 (+-0.000466561)
found -0.82 (+-0.000120969) 46.5433 (+-0.0925557) 7.00006 (+-0.00046687)
found -0.460001 (+-0.000120781) 46.5433 (+-0.09254) 7.00005 (+-0.000466791)
found 5.66 (+-0.000120781) 46.5433 (+-0.09254) 7.00005 (+-0.000466791)
found 6.02 (+-0.000121464) 46.5436 (+-0.0926014) 7.00009 (+-0.000467101)
found 6.38 (+-0.000121532) 46.5436 (+-0.0926081) 7.0001 (+-0.000467135)
found 8.54 (+-0.000120294) 46.5431 (+-0.0924943) 7.00002 (+-0.000466561)
found 9.26 (+-0.000120535) 46.5432 (+-0.0925162) 7.00003 (+-0.000466671)
found -7.3 (+-0.00013103) 39.8944 (+-0.0857195) 6.00007 (+-0.000432387)
found -4.78 (+-0.000131443) 39.8946 (+-0.0857531) 6.0001 (+-0.000432557)
found 3.5 (+-0.00013101) 39.8945 (+-0.0857195) 6.00008 (+-0.000432388)
found -2.98 (+-0.000130901) 39.8943 (+-0.085708) 6.00006 (+-0.000432329)
found -5.5 (+-0.000144319) 33.2457 (+-0.0783053) 5.00011 (+-0.000394988)
found 7.1 (+-0.000143305) 33.2454 (+-0.0782378) 5.00006 (+-0.000394648)
found -9.1 (+-0.000143463) 33.2455 (+-0.0782496) 5.00007 (+-0.000394708)
found -3.34 (+-0.000143373) 33.2453 (+-0.0782398) 5.00005 (+-0.000394658)
found 0.26 (+-0.000142312) 33.2451 (+-0.0781704) 5.00001 (+-0.000394308)
found 4.94 (+-0.000142887) 33.2452 (+-0.0782078) 5.00003 (+-0.000394497)
found -8.02 (+-0.000161817) 26.5967 (+-0.0700656) 4.00011 (+-0.000353426)
found -2.62 (+-0.000160255) 26.5963 (+-0.0699791) 4.00005 (+-0.00035299)
found 4.58 (+-0.00016135) 26.5965 (+-0.0700384) 4.00009 (+-0.000353289)
found 9.62 (+-0.000159506) 26.5965 (+-0.0699505) 4.00007 (+-0.000352845)
found 2.78 (+-0.000161209) 26.5966 (+-0.0700317) 4.00009 (+-0.000353255)
found -6.94 (+-0.000187027) 19.9476 (+-0.0606866) 3.00009 (+-0.000306116)
found -6.22 (+-0.000187322) 19.9477 (+-0.0606999) 3.00011 (+-0.000306183)
found 2.42 (+-0.000186657) 19.9475 (+-0.0606706) 3.00008 (+-0.000306035)
found -9.82 (+-0.000184398) 19.947 (+-0.0605709) 3.00001 (+-0.000305532)
found 1.34 (+-0.000228647) 13.2985 (+-0.0495428) 2.00007 (+-0.000249904)
found 8.18 (+-0.000230552) 13.2987 (+-0.0495962) 2.00011 (+-0.000250174)
found -3.7 (+-0.000229713) 13.2985 (+-0.0495702) 2.00008 (+-0.000250043)
found -1.18 (+-0.000230174) 13.2986 (+-0.0495843) 2.00009 (+-0.000250114)
found 3.86 (+-0.000230153) 13.2986 (+-0.0495838) 2.00009 (+-0.000250111)
found 8.9 (+-0.000328708) 6.64962 (+-0.0351126) 1.00009 (+-0.000177115)
found -0.100001 (+-0.000327884) 6.64953 (+-0.0350992) 1.00008 (+-0.000177048)
found 0.620003 (+-0.00032885) 6.64967 (+-0.0351155) 1.0001 (+-0.00017713)
found 5.3 (+-0.000327884) 6.64953 (+-0.0350992) 1.00008 (+-0.000177048)
found 7.46 (+-0.000328553) 6.64962 (+-0.0351105) 1.00009 (+-0.000177105)
found -9.46 (+-0.000325978) 6.64935 (+-0.0350689) 1.00005 (+-0.000176895)
found -2.26 (+-0.000323693) 6.64922 (+-0.035035) 1.00003 (+-0.000176724)
found -1.9 (+-0.000324974) 6.64935 (+-0.0350562) 1.00005 (+-0.000176831)
found 1.7 (+-0.000326381) 6.64945 (+-0.0350769) 1.00007 (+-0.000176935)

 
#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.