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 26.5962 4
created -9.46 53.1923 8
created -9.1 46.5433 7
created -8.74 6.64904 1
created -8.38 33.2452 5
created -8.02 33.2452 5
created -7.66 26.5962 4
created -7.3 46.5433 7
created -6.94 33.2452 5
created -6.58 46.5433 7
created -6.22 19.9471 3
created -5.86 39.8942 6
created -5.5 46.5433 7
created -5.14 59.8413 9
created -4.78 26.5962 4
created -4.42 6.64904 1
created -4.06 53.1923 8
created -3.7 6.64904 1
created -3.34 26.5962 4
created -2.98 53.1923 8
created -2.62 39.8942 6
created -2.26 66.4904 10
created -1.9 46.5433 7
created -1.54 33.2452 5
created -1.18 39.8942 6
created -0.82 26.5962 4
created -0.46 46.5433 7
created -0.1 53.1923 8
created 0.26 46.5433 7
created 0.62 19.9471 3
created 0.98 59.8413 9
created 1.34 26.5962 4
created 1.7 53.1923 8
created 2.06 66.4904 10
created 2.42 33.2452 5
created 2.78 6.64904 1
created 3.14 53.1923 8
created 3.5 39.8942 6
created 3.86 46.5433 7
created 4.22 53.1923 8
created 4.58 19.9471 3
created 4.94 59.8413 9
created 5.3 6.64904 1
created 5.66 66.4904 10
created 6.02 33.2452 5
created 6.38 13.2981 2
created 6.74 19.9471 3
created 7.1 6.64904 1
created 7.46 6.64904 1
created 7.82 6.64904 1
created 8.18 33.2452 5
created 8.54 59.8413 9
created 8.9 53.1923 8
created 9.26 46.5433 7
created 9.62 6.64904 1
the total number of created peaks = 55 with sigma = 0.06
the total number of found peaks = 55 with sigma = 0.0600004 (+-5.49931e-06)
fit chi^2 = 4.15757e-07
found -2.26 (+-5.24276e-05) 66.4905 (+-0.0572621) 10.0001 (+-0.000288842)
found 2.06 (+-5.24219e-05) 66.4905 (+-0.0572614) 10.0001 (+-0.000288839)
found 5.66 (+-5.21407e-05) 66.4902 (+-0.0572259) 10 (+-0.00028866)
found -5.14 (+-5.52317e-05) 59.8414 (+-0.0543199) 9.00007 (+-0.000274001)
found 0.98 (+-5.50834e-05) 59.8412 (+-0.0543023) 9.00005 (+-0.000273912)
found 4.94 (+-5.49063e-05) 59.8411 (+-0.0542828) 9.00003 (+-0.000273814)
found 8.54 (+-5.52985e-05) 59.8415 (+-0.0543279) 9.00009 (+-0.000274042)
found 8.9 (+-5.88044e-05) 53.1926 (+-0.0512374) 8.00011 (+-0.000258453)
found -9.46 (+-5.86294e-05) 53.1924 (+-0.0512184) 8.00007 (+-0.000258356)
found -4.06 (+-5.81222e-05) 53.192 (+-0.051167) 8.00001 (+-0.000258097)
found -2.98 (+-5.85955e-05) 53.1924 (+-0.0512147) 8.00007 (+-0.000258338)
found -0.1 (+-5.87445e-05) 53.1925 (+-0.0512308) 8.00009 (+-0.000258419)
found 1.7 (+-5.87156e-05) 53.1926 (+-0.0512281) 8.00009 (+-0.000258405)
found 3.14 (+-5.83973e-05) 53.1922 (+-0.0511951) 8.00005 (+-0.000258239)
found 4.22 (+-5.8579e-05) 53.1924 (+-0.0512132) 8.00007 (+-0.00025833)
found -9.1 (+-6.25481e-05) 46.5433 (+-0.0479001) 7.00006 (+-0.000241618)
found -1.9 (+-6.28832e-05) 46.5436 (+-0.0479303) 7.0001 (+-0.000241771)
found 0.26 (+-6.27156e-05) 46.5434 (+-0.0479144) 7.00007 (+-0.00024169)
found 9.26 (+-6.25481e-05) 46.5433 (+-0.0479001) 7.00006 (+-0.000241618)
found -7.3 (+-6.26572e-05) 46.5433 (+-0.0479084) 7.00006 (+-0.00024166)
found -6.58 (+-6.26007e-05) 46.5433 (+-0.0479032) 7.00005 (+-0.000241634)
found -5.5 (+-6.2896e-05) 46.5436 (+-0.0479314) 7.0001 (+-0.000241776)
found -0.46 (+-6.27725e-05) 46.5435 (+-0.0479196) 7.00008 (+-0.000241717)
found 3.86 (+-6.28637e-05) 46.5436 (+-0.0479282) 7.00009 (+-0.00024176)
found -2.62 (+-6.81435e-05) 39.8948 (+-0.0443935) 6.00012 (+-0.00022393)
found 3.5 (+-6.8032e-05) 39.8946 (+-0.0443839) 6.0001 (+-0.000223882)
found -5.86 (+-6.77787e-05) 39.8944 (+-0.0443631) 6.00007 (+-0.000223777)
found -1.18 (+-6.77517e-05) 39.8943 (+-0.0443605) 6.00006 (+-0.000223764)
found 2.42 (+-7.42534e-05) 33.2455 (+-0.0405003) 5.00007 (+-0.000204292)
found 6.02 (+-7.43858e-05) 33.2455 (+-0.0405084) 5.00008 (+-0.000204333)
found -8.38 (+-7.40189e-05) 33.2452 (+-0.0404831) 5.00004 (+-0.000204205)
found -8.02 (+-7.43205e-05) 33.2454 (+-0.0405025) 5.00006 (+-0.000204303)
found -6.94 (+-7.46024e-05) 33.2456 (+-0.0405223) 5.00009 (+-0.000204403)
found -1.54 (+-7.4551e-05) 33.2455 (+-0.0405186) 5.00009 (+-0.000204385)
found 8.18 (+-7.4214e-05) 33.2454 (+-0.0404973) 5.00007 (+-0.000204277)
found -7.66 (+-8.34544e-05) 26.5965 (+-0.036247) 4.00008 (+-0.000182837)
found -4.78 (+-8.31124e-05) 26.5964 (+-0.0362297) 4.00007 (+-0.00018275)
found -0.82 (+-8.3524e-05) 26.5965 (+-0.036251) 4.00009 (+-0.000182857)
found 1.34 (+-8.37527e-05) 26.5967 (+-0.0362644) 4.00011 (+-0.000182925)
found -9.82 (+-8.32214e-05) 26.5963 (+-0.0362316) 4.00005 (+-0.00018276)
found -3.34 (+-8.30612e-05) 26.5964 (+-0.0362266) 4.00006 (+-0.000182735)
found -6.22 (+-9.67285e-05) 19.9476 (+-0.0314068) 3.00009 (+-0.000158422)
found 0.62 (+-9.69479e-05) 19.9477 (+-0.0314167) 3.00011 (+-0.000158472)
found 4.58 (+-9.70209e-05) 19.9477 (+-0.03142) 3.00011 (+-0.000158489)
found 6.74 (+-9.55326e-05) 19.9471 (+-0.0313564) 3.00002 (+-0.000158169)
found 6.38 (+-0.000118343) 13.2983 (+-0.0256399) 2.00005 (+-0.000129333)
found 5.3 (+-0.000170988) 6.64985 (+-0.0181878) 1.00013 (+-9.1743e-05)
found -3.7 (+-0.000169626) 6.64953 (+-0.0181655) 1.00008 (+-9.16307e-05)
found -8.74 (+-0.000169705) 6.64953 (+-0.0181666) 1.00008 (+-9.1636e-05)
found 2.78 (+-0.000169886) 6.64958 (+-0.0181696) 1.00009 (+-9.16512e-05)
found 9.62 (+-0.00016652) 6.64935 (+-0.0181254) 1.00005 (+-9.14282e-05)
found -4.42 (+-0.000169626) 6.64953 (+-0.0181655) 1.00008 (+-9.16307e-05)
found 7.1 (+-0.000167239) 6.64917 (+-0.0181287) 1.00003 (+-9.14448e-05)
found 7.46 (+-0.000166331) 6.64908 (+-0.0181153) 1.00001 (+-9.13772e-05)
found 7.82 (+-0.000167787) 6.64926 (+-0.0181374) 1.00004 (+-9.1489e-05)

 
#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.