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 6.64904 1
created -9.46 6.64904 1
created -9.1 66.4904 10
created -8.74 39.8942 6
created -8.38 26.5962 4
created -8.02 13.2981 2
created -7.66 46.5433 7
created -7.3 59.8413 9
created -6.94 46.5433 7
created -6.58 59.8413 9
created -6.22 26.5962 4
created -5.86 33.2452 5
created -5.5 66.4904 10
created -5.14 39.8942 6
created -4.78 53.1923 8
created -4.42 26.5962 4
created -4.06 59.8413 9
created -3.7 46.5433 7
created -3.34 26.5962 4
created -2.98 6.64904 1
created -2.62 46.5433 7
created -2.26 66.4904 10
created -1.9 26.5962 4
created -1.54 13.2981 2
created -1.18 53.1923 8
created -0.82 19.9471 3
created -0.46 39.8942 6
created -0.1 66.4904 10
created 0.26 13.2981 2
created 0.62 39.8942 6
created 0.98 66.4904 10
created 1.34 39.8942 6
created 1.7 19.9471 3
created 2.06 53.1923 8
created 2.42 13.2981 2
created 2.78 26.5962 4
created 3.14 33.2452 5
created 3.5 26.5962 4
created 3.86 13.2981 2
created 4.22 39.8942 6
created 4.58 6.64904 1
created 4.94 59.8413 9
created 5.3 33.2452 5
created 5.66 46.5433 7
created 6.02 39.8942 6
created 6.38 6.64904 1
created 6.74 26.5962 4
created 7.1 46.5433 7
created 7.46 53.1923 8
created 7.82 39.8942 6
created 8.18 39.8942 6
created 8.54 19.9471 3
created 8.9 19.9471 3
created 9.26 59.8413 9
created 9.62 59.8413 9
the total number of created peaks = 55 with sigma = 0.06
the total number of found peaks = 55 with sigma = 0.0600004 (+-1.56118e-05)
fit chi^2 = 3.43124e-06
found -9.1 (+-0.000149878) 66.4902 (+-0.164411) 10 (+-0.000829323)
found -5.5 (+-0.000150444) 66.4904 (+-0.16448) 10.0001 (+-0.000829673)
found -2.26 (+-0.000150423) 66.4904 (+-0.164478) 10.0001 (+-0.000829661)
found -0.1 (+-0.000150078) 66.4903 (+-0.164434) 10.0001 (+-0.000829441)
found 0.98 (+-0.000150534) 66.4904 (+-0.164492) 10.0001 (+-0.000829733)
found 9.62 (+-0.000157723) 59.8417 (+-0.155962) 9.00012 (+-0.000786707)
found -7.3 (+-0.000158968) 59.8415 (+-0.156086) 9.00009 (+-0.000787332)
found -6.58 (+-0.00015867) 59.8414 (+-0.156051) 9.00007 (+-0.000787152)
found -4.06 (+-0.00015867) 59.8414 (+-0.156051) 9.00007 (+-0.000787152)
found 4.94 (+-0.000157974) 59.8412 (+-0.155972) 9.00004 (+-0.000786755)
found 9.26 (+-0.000158693) 59.8415 (+-0.156055) 9.00008 (+-0.000787174)
found -4.78 (+-0.000168334) 53.1924 (+-0.14713) 8.00007 (+-0.000742154)
found -1.18 (+-0.000167637) 53.1922 (+-0.147057) 8.00003 (+-0.000741788)
found 2.06 (+-0.000167637) 53.1922 (+-0.147057) 8.00003 (+-0.000741788)
found 7.46 (+-0.000168664) 53.1925 (+-0.147165) 8.00009 (+-0.000742333)
found -6.94 (+-0.000180992) 46.5437 (+-0.137727) 7.00012 (+-0.000694726)
found -3.7 (+-0.000180425) 46.5435 (+-0.137673) 7.00009 (+-0.000694451)
found -7.66 (+-0.000180059) 46.5434 (+-0.13764) 7.00007 (+-0.000694286)
found -2.62 (+-0.000179865) 46.5434 (+-0.137625) 7.00007 (+-0.000694212)
found 5.66 (+-0.000180263) 46.5434 (+-0.137656) 7.00007 (+-0.000694367)
found 7.1 (+-0.000180333) 46.5435 (+-0.137664) 7.00008 (+-0.000694405)
found -8.74 (+-0.00019522) 39.8946 (+-0.127489) 6.00009 (+-0.000643082)
found -5.14 (+-0.000195763) 39.8948 (+-0.127534) 6.00012 (+-0.000643309)
found 1.34 (+-0.000195032) 39.8945 (+-0.127474) 6.00009 (+-0.000643007)
found 7.82 (+-0.000195316) 39.8946 (+-0.127496) 6.00009 (+-0.000643116)
found -0.459999 (+-0.000195032) 39.8945 (+-0.127474) 6.00009 (+-0.000643007)
found 0.620001 (+-0.000194799) 39.8945 (+-0.127456) 6.00008 (+-0.000642917)
found 4.22 (+-0.000193333) 39.8941 (+-0.127338) 6.00002 (+-0.000642319)
found 6.02 (+-0.000194163) 39.8943 (+-0.127406) 6.00005 (+-0.00064266)
found 8.18 (+-0.00019459) 39.8944 (+-0.127436) 6.00006 (+-0.000642814)
found 5.3 (+-0.000214577) 33.2457 (+-0.116431) 5.00011 (+-0.000587305)
found -5.86 (+-0.000214191) 33.2456 (+-0.116405) 5.00009 (+-0.000587172)
found 3.14 (+-0.000213323) 33.2453 (+-0.116343) 5.00005 (+-0.000586858)
found -8.38 (+-0.000238744) 26.5963 (+-0.104075) 4.00005 (+-0.000524977)
found -6.22 (+-0.00024006) 26.5966 (+-0.104149) 4.00009 (+-0.00052535)
found -4.42 (+-0.000240605) 26.5967 (+-0.104181) 4.00011 (+-0.000525509)
found -3.34 (+-0.000238459) 26.5963 (+-0.104062) 4.00005 (+-0.000524913)
found -1.9 (+-0.000239368) 26.5965 (+-0.104113) 4.00008 (+-0.000525166)
found 3.5 (+-0.000238547) 26.5963 (+-0.104064) 4.00005 (+-0.00052492)
found 2.78 (+-0.000238547) 26.5963 (+-0.104064) 4.00005 (+-0.00052492)
found 6.74 (+-0.000238459) 26.5963 (+-0.104062) 4.00005 (+-0.000524913)
found -0.82 (+-0.00027809) 19.9476 (+-0.090235) 3.00009 (+-0.000455164)
found 1.7 (+-0.00027809) 19.9476 (+-0.090235) 3.00009 (+-0.000455164)
found 8.54 (+-0.000276762) 19.9474 (+-0.090177) 3.00006 (+-0.000454872)
found 8.9 (+-0.000277384) 19.9475 (+-0.0902054) 3.00008 (+-0.000455015)
found 0.259999 (+-0.000342732) 13.2987 (+-0.0737427) 2.00011 (+-0.000371974)
found 2.42 (+-0.000341435) 13.2985 (+-0.0737028) 2.00008 (+-0.000371773)
found -8.02 (+-0.000341145) 13.2985 (+-0.0736937) 2.00007 (+-0.000371726)
found -1.54 (+-0.000341435) 13.2985 (+-0.0737028) 2.00008 (+-0.000371773)
found 3.86 (+-0.000340824) 13.2984 (+-0.0736837) 2.00007 (+-0.000371676)
found 4.58 (+-0.000489178) 6.64967 (+-0.0522162) 1.0001 (+-0.000263389)
found -2.98 (+-0.000486786) 6.64949 (+-0.0521773) 1.00007 (+-0.000263193)
found 6.38 (+-0.000486216) 6.64944 (+-0.0521679) 1.00007 (+-0.000263146)
found -9.45999 (+-0.000484603) 6.64949 (+-0.0521493) 1.00008 (+-0.000263052)
found -9.82 (+-0.00047664) 6.64904 (+-0.0520211) 1.00001 (+-0.000262405)

 
#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.