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 53.1923 8
created -9.1 19.9471 3
created -8.74 19.9471 3
created -8.38 46.5433 7
created -8.02 39.8942 6
created -7.66 33.2452 5
created -7.3 19.9471 3
created -6.94 13.2981 2
created -6.58 66.4904 10
created -6.22 6.64904 1
created -5.86 33.2452 5
created -5.5 6.64904 1
created -5.14 39.8942 6
created -4.78 53.1923 8
created -4.42 46.5433 7
created -4.06 33.2452 5
created -3.7 66.4904 10
created -3.34 39.8942 6
created -2.98 33.2452 5
created -2.62 53.1923 8
created -2.26 6.64904 1
created -1.9 33.2452 5
created -1.54 46.5433 7
created -1.18 26.5962 4
created -0.82 6.64904 1
created -0.46 6.64904 1
created -0.1 19.9471 3
created 0.26 6.64904 1
created 0.62 6.64904 1
created 0.98 53.1923 8
created 1.34 53.1923 8
created 1.7 46.5433 7
created 2.06 26.5962 4
created 2.42 66.4904 10
created 2.78 26.5962 4
created 3.14 19.9471 3
created 3.5 66.4904 10
created 3.86 26.5962 4
created 4.22 26.5962 4
created 4.58 59.8413 9
created 4.94 6.64904 1
created 5.3 33.2452 5
created 5.66 59.8413 9
created 6.02 46.5433 7
created 6.38 33.2452 5
created 6.74 6.64904 1
created 7.1 66.4904 10
created 7.46 19.9471 3
created 7.82 6.64904 1
created 8.18 53.1923 8
created 8.54 19.9471 3
created 8.9 53.1923 8
created 9.26 13.2981 2
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 (+-1.52882e-05)
fit chi^2 = 3.06093e-06
found -9.82 (+-0.000142238) 66.4903 (+-0.155358) 10.0001 (+-0.000783656)
found -6.58 (+-0.000141135) 66.49 (+-0.155231) 10 (+-0.000783018)
found -3.7 (+-0.000142094) 66.4904 (+-0.155351) 10.0001 (+-0.000783624)
found 2.42 (+-0.000141819) 66.4903 (+-0.155315) 10.0001 (+-0.000783443)
found 3.5 (+-0.000141708) 66.4902 (+-0.155301) 10 (+-0.000783371)
found 7.1 (+-0.000141271) 66.4901 (+-0.155248) 10 (+-0.000783103)
found 4.58 (+-0.000149102) 59.8412 (+-0.147303) 9.00003 (+-0.000743026)
found 5.66 (+-0.000149969) 59.8415 (+-0.147402) 9.00008 (+-0.000743526)
found -9.46 (+-0.000159179) 53.1925 (+-0.138986) 8.00009 (+-0.000701075)
found 1.34 (+-0.000159479) 53.1926 (+-0.139017) 8.0001 (+-0.00070123)
found -4.78 (+-0.000159302) 53.1925 (+-0.138997) 8.00009 (+-0.000701132)
found -2.62 (+-0.000158352) 53.1922 (+-0.1389) 8.00004 (+-0.000700639)
found 0.980001 (+-0.000158627) 53.1923 (+-0.13893) 8.00006 (+-0.000700793)
found 8.18 (+-0.000158102) 53.1921 (+-0.138873) 8.00003 (+-0.000700506)
found 8.9 (+-0.000158333) 53.1922 (+-0.138895) 8.00003 (+-0.000700617)
found 9.62 (+-0.000157322) 53.1924 (+-0.138808) 8.00007 (+-0.000700176)
found -4.42 (+-0.000170456) 46.5435 (+-0.130035) 7.00009 (+-0.000655925)
found 1.7 (+-0.000170324) 46.5435 (+-0.130023) 7.00008 (+-0.000655863)
found 6.02 (+-0.000170543) 46.5436 (+-0.130044) 7.00009 (+-0.000655969)
found -8.38 (+-0.000169973) 46.5433 (+-0.12999) 7.00006 (+-0.000655695)
found -1.54 (+-0.000170012) 46.5433 (+-0.129993) 7.00006 (+-0.00065571)
found -3.34 (+-0.000184536) 39.8946 (+-0.120425) 6.0001 (+-0.000607451)
found -8.02 (+-0.000184235) 39.8945 (+-0.120399) 6.00008 (+-0.000607319)
found -5.14 (+-0.000183493) 39.8944 (+-0.120343) 6.00006 (+-0.000607038)
found -7.66 (+-0.000201606) 33.2454 (+-0.109895) 5.00006 (+-0.000554332)
found -5.86 (+-0.00019986) 33.2451 (+-0.109781) 5.00001 (+-0.000553756)
found -4.06 (+-0.000202777) 33.2457 (+-0.109977) 5.00011 (+-0.000554749)
found -2.98 (+-0.00020241) 33.2456 (+-0.109951) 5.00009 (+-0.000554615)
found -1.9 (+-0.000201129) 33.2453 (+-0.109866) 5.00005 (+-0.000554187)
found 5.3 (+-0.000201369) 33.2454 (+-0.109884) 5.00007 (+-0.000554276)
found 6.38 (+-0.000201129) 33.2453 (+-0.109866) 5.00005 (+-0.000554187)
found -1.18 (+-0.000225224) 26.5963 (+-0.0982867) 4.00005 (+-0.000495779)
found 2.06 (+-0.000227228) 26.5967 (+-0.0983972) 4.00011 (+-0.000496336)
found 2.78 (+-0.000226397) 26.5966 (+-0.0983507) 4.00009 (+-0.000496101)
found 3.86 (+-0.000226652) 26.5966 (+-0.0983645) 4.00009 (+-0.000496171)
found 4.22 (+-0.000226521) 26.5966 (+-0.0983565) 4.00009 (+-0.000496131)
found -9.1 (+-0.00026181) 19.9475 (+-0.0851905) 3.00007 (+-0.000429719)
found -7.3 (+-0.000260759) 19.9473 (+-0.0851449) 3.00005 (+-0.000429489)
found 3.14 (+-0.000262482) 19.9476 (+-0.0852202) 3.00009 (+-0.000429869)
found 7.46 (+-0.00026118) 19.9475 (+-0.0851684) 3.00007 (+-0.000429607)
found 8.54 (+-0.000263071) 19.9477 (+-0.0852453) 3.00011 (+-0.000429995)
found -8.74 (+-0.000261615) 19.9474 (+-0.0851816) 3.00007 (+-0.000429674)
found -0.1 (+-0.000258662) 19.9471 (+-0.0850596) 3.00001 (+-0.000429058)
found 9.26 (+-0.000323805) 13.2987 (+-0.0696522) 2.00011 (+-0.000351341)
found -6.94 (+-0.000322504) 13.2986 (+-0.0696143) 2.00009 (+-0.000351149)
found -6.22 (+-0.000461828) 6.64967 (+-0.0493153) 1.0001 (+-0.000248757)
found -2.26 (+-0.000460962) 6.64958 (+-0.0493006) 1.00009 (+-0.000248683)
found 4.94 (+-0.000461412) 6.64962 (+-0.0493082) 1.00009 (+-0.000248721)
found 6.74 (+-0.000461828) 6.64967 (+-0.0493153) 1.0001 (+-0.000248757)
found -5.5 (+-0.00045993) 6.64949 (+-0.0492835) 1.00007 (+-0.000248596)
found 7.82 (+-0.000459418) 6.64949 (+-0.0492767) 1.00007 (+-0.000248562)
found -0.820002 (+-0.000454586) 6.64922 (+-0.0492023) 1.00003 (+-0.000248187)
found 0.259999 (+-0.000453778) 6.64917 (+-0.0491895) 1.00003 (+-0.000248122)
found 0.620004 (+-0.000456863) 6.6494 (+-0.0492402) 1.00006 (+-0.000248378)
found -0.459999 (+-0.000453778) 6.64917 (+-0.0491895) 1.00003 (+-0.000248122)

 
#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.