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 46.5433 7
created -9.46 26.5962 4
created -9.1 13.2981 2
created -8.74 33.2452 5
created -8.38 13.2981 2
created -8.02 26.5962 4
created -7.66 39.8942 6
created -7.3 53.1923 8
created -6.94 59.8413 9
created -6.58 26.5962 4
created -6.22 33.2452 5
created -5.86 26.5962 4
created -5.5 13.2981 2
created -5.14 26.5962 4
created -4.78 33.2452 5
created -4.42 66.4904 10
created -4.06 33.2452 5
created -3.7 19.9471 3
created -3.34 33.2452 5
created -2.98 59.8413 9
created -2.62 6.64904 1
created -2.26 26.5962 4
created -1.9 46.5433 7
created -1.54 13.2981 2
created -1.18 33.2452 5
created -0.82 46.5433 7
created -0.46 13.2981 2
created -0.1 66.4904 10
created 0.26 33.2452 5
created 0.62 59.8413 9
created 0.98 13.2981 2
created 1.34 53.1923 8
created 1.7 53.1923 8
created 2.06 26.5962 4
created 2.42 53.1923 8
created 2.78 26.5962 4
created 3.14 46.5433 7
created 3.5 26.5962 4
created 3.86 13.2981 2
created 4.22 19.9471 3
created 4.58 46.5433 7
created 4.94 26.5962 4
created 5.3 46.5433 7
created 5.66 13.2981 2
created 6.02 46.5433 7
created 6.38 33.2452 5
created 6.74 26.5962 4
created 7.1 59.8413 9
created 7.46 19.9471 3
created 7.82 19.9471 3
created 8.18 6.64904 1
created 8.54 26.5962 4
created 8.9 13.2981 2
created 9.26 19.9471 3
created 9.62 13.2981 2
the total number of created peaks = 55 with sigma = 0.06
the total number of found peaks = 55 with sigma = 0.0600004 (+-7.97831e-06)
fit chi^2 = 7.83855e-07
found -4.42 (+-7.18639e-05) 66.4904 (+-0.0786094) 10.0001 (+-0.000396523)
found -0.0999998 (+-7.16892e-05) 66.4902 (+-0.0785874) 10 (+-0.000396412)
found -6.94 (+-7.58763e-05) 59.8415 (+-0.0745908) 9.00008 (+-0.000376252)
found -2.98 (+-7.55052e-05) 59.8412 (+-0.0745484) 9.00004 (+-0.000376038)
found 0.62 (+-7.56104e-05) 59.8412 (+-0.0745596) 9.00005 (+-0.000376094)
found 7.1 (+-7.56343e-05) 59.8412 (+-0.0745619) 9.00005 (+-0.000376106)
found 1.7 (+-8.05459e-05) 53.1925 (+-0.0703321) 8.00008 (+-0.00035477)
found -7.3 (+-8.06966e-05) 53.1926 (+-0.0703484) 8.0001 (+-0.000354852)
found 1.34 (+-8.03907e-05) 53.1924 (+-0.0703164) 8.00007 (+-0.000354691)
found 2.42 (+-8.03463e-05) 53.1923 (+-0.0703104) 8.00005 (+-0.000354661)
found -9.82 (+-8.59297e-05) 46.5431 (+-0.0657672) 7.00003 (+-0.000331744)
found -1.9 (+-8.57944e-05) 46.5432 (+-0.0657606) 7.00004 (+-0.00033171)
found -0.82 (+-8.58601e-05) 46.5433 (+-0.0657668) 7.00005 (+-0.000331742)
found 3.14 (+-8.59678e-05) 46.5433 (+-0.0657762) 7.00005 (+-0.000331789)
found 4.58 (+-8.58903e-05) 46.5432 (+-0.0657691) 7.00005 (+-0.000331753)
found 5.3 (+-8.57944e-05) 46.5432 (+-0.0657606) 7.00004 (+-0.00033171)
found 6.02 (+-8.58601e-05) 46.5432 (+-0.0657668) 7.00005 (+-0.000331742)
found -7.66 (+-9.32101e-05) 39.8945 (+-0.0609262) 6.00008 (+-0.000307325)
found -4.06 (+-0.000102269) 33.2455 (+-0.05563) 5.00009 (+-0.00028061)
found 0.26 (+-0.000102739) 33.2458 (+-0.0556628) 5.00013 (+-0.000280775)
found -8.74 (+-0.000101494) 33.2451 (+-0.0555764) 5.00003 (+-0.000280339)
found -6.22 (+-0.00010196) 33.2453 (+-0.0556073) 5.00005 (+-0.000280495)
found -4.78 (+-0.000102375) 33.2456 (+-0.055637) 5.00009 (+-0.000280645)
found -3.34 (+-0.000102214) 33.2455 (+-0.0556259) 5.00008 (+-0.000280589)
found -1.18 (+-0.000101962) 33.2454 (+-0.0556085) 5.00006 (+-0.000280501)
found 6.38 (+-0.000102197) 33.2454 (+-0.055624) 5.00007 (+-0.000280579)
found -9.46 (+-0.000114195) 26.5964 (+-0.0497488) 4.00006 (+-0.000250944)
found -6.58 (+-0.000114739) 26.5966 (+-0.0497792) 4.00009 (+-0.000251097)
found -5.86 (+-0.000114016) 26.5963 (+-0.0497384) 4.00005 (+-0.000250891)
found 2.06 (+-0.000114928) 26.5967 (+-0.0497899) 4.00011 (+-0.000251151)
found 2.78 (+-0.00011485) 26.5966 (+-0.0497853) 4.0001 (+-0.000251128)
found 3.5 (+-0.000114195) 26.5964 (+-0.0497488) 4.00006 (+-0.000250944)
found 4.94 (+-0.000114772) 26.5966 (+-0.0497807) 4.00009 (+-0.000251105)
found 6.74 (+-0.000114739) 26.5966 (+-0.0497792) 4.00009 (+-0.000251097)
found -8.02 (+-0.00011411) 26.5963 (+-0.0497439) 4.00005 (+-0.000250919)
found -5.14 (+-0.000114016) 26.5963 (+-0.0497384) 4.00005 (+-0.000250891)
found -2.26 (+-0.000113974) 26.5963 (+-0.0497377) 4.00005 (+-0.000250888)
found 8.54 (+-0.000113409) 26.5961 (+-0.0497059) 4.00002 (+-0.000250727)
found -3.7 (+-0.000132463) 19.9474 (+-0.0431086) 3.00007 (+-0.000217449)
found 7.46 (+-0.000132579) 19.9475 (+-0.0431146) 3.00008 (+-0.000217479)
found 4.22 (+-0.000132185) 19.9474 (+-0.0430976) 3.00006 (+-0.000217394)
found 7.82 (+-0.000131375) 19.9472 (+-0.0430635) 3.00003 (+-0.000217221)
found 9.26 (+-0.000131456) 19.9472 (+-0.0430662) 3.00003 (+-0.000217235)
found 0.98 (+-0.00016399) 13.2987 (+-0.0352514) 2.00011 (+-0.000177816)
found -1.54 (+-0.000163252) 13.2985 (+-0.0352286) 2.00008 (+-0.0001777)
found -0.459999 (+-0.000163968) 13.2987 (+-0.0352509) 2.00011 (+-0.000177813)
found 5.66 (+-0.00016358) 13.2986 (+-0.0352386) 2.00009 (+-0.000177751)
found -9.1 (+-0.000162729) 13.2984 (+-0.0352127) 2.00006 (+-0.00017762)
found -8.38 (+-0.000162729) 13.2984 (+-0.0352127) 2.00006 (+-0.00017762)
found -5.5 (+-0.000162533) 13.2983 (+-0.0352068) 2.00005 (+-0.000177591)
found 3.86 (+-0.0001623) 13.2983 (+-0.0352) 2.00005 (+-0.000177556)
found 8.9 (+-0.0001623) 13.2983 (+-0.0352) 2.00005 (+-0.000177556)
found 9.62 (+-0.000160195) 13.2982 (+-0.0351485) 2.00003 (+-0.000177296)
found -2.62 (+-0.000233138) 6.64958 (+-0.0249467) 1.00009 (+-0.000125836)
found 8.18 (+-0.000231316) 6.64931 (+-0.0249172) 1.00005 (+-0.000125687)

 
#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.