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 59.8413 9
created -9.46 19.9471 3
created -9.1 66.4904 10
created -8.74 53.1923 8
created -8.38 66.4904 10
created -8.02 66.4904 10
created -7.66 6.64904 1
created -7.3 66.4904 10
created -6.94 26.5962 4
created -6.58 6.64904 1
created -6.22 46.5433 7
created -5.86 19.9471 3
created -5.5 26.5962 4
created -5.14 66.4904 10
created -4.78 53.1923 8
created -4.42 6.64904 1
created -4.06 13.2981 2
created -3.7 13.2981 2
created -3.34 46.5433 7
created -2.98 53.1923 8
created -2.62 19.9471 3
created -2.26 19.9471 3
created -1.9 39.8942 6
created -1.54 39.8942 6
created -1.18 39.8942 6
created -0.82 19.9471 3
created -0.46 39.8942 6
created -0.1 46.5433 7
created 0.26 39.8942 6
created 0.62 26.5962 4
created 0.98 66.4904 10
created 1.34 39.8942 6
created 1.7 26.5962 4
created 2.06 26.5962 4
created 2.42 59.8413 9
created 2.78 6.64904 1
created 3.14 19.9471 3
created 3.5 39.8942 6
created 3.86 33.2452 5
created 4.22 59.8413 9
created 4.58 6.64904 1
created 4.94 59.8413 9
created 5.3 66.4904 10
created 5.66 13.2981 2
created 6.02 39.8942 6
created 6.38 39.8942 6
created 6.74 59.8413 9
created 7.1 46.5433 7
created 7.46 66.4904 10
created 7.82 26.5962 4
created 8.18 59.8413 9
created 8.54 33.2452 5
created 8.9 39.8942 6
created 9.26 39.8942 6
created 9.62 33.2452 5
the total number of created peaks = 55 with sigma = 0.06
the total number of found peaks = 55 with sigma = 0.0600004 (+-1.14535e-05)
fit chi^2 = 1.92907e-06
found -9.1 (+-0.000112754) 66.4904 (+-0.123322) 10.0001 (+-0.000622065)
found -8.38 (+-0.0001132) 66.4907 (+-0.123382) 10.0001 (+-0.000622363)
found -8.02 (+-0.00011259) 66.4904 (+-0.123305) 10.0001 (+-0.000621977)
found -7.3 (+-0.000112238) 66.4901 (+-0.123257) 10 (+-0.000621736)
found -5.14 (+-0.000112843) 66.4904 (+-0.123334) 10.0001 (+-0.000622121)
found 0.98 (+-0.000112728) 66.4904 (+-0.123318) 10.0001 (+-0.000622043)
found 5.3 (+-0.000112694) 66.4904 (+-0.123316) 10.0001 (+-0.000622032)
found 7.46 (+-0.000112788) 66.4904 (+-0.123326) 10.0001 (+-0.000622084)
found -9.82 (+-0.000118693) 59.8411 (+-0.116965) 9.00002 (+-0.000589994)
found 2.42 (+-0.000118367) 59.8411 (+-0.116939) 9.00003 (+-0.000589863)
found 4.22 (+-0.000118449) 59.8412 (+-0.116948) 9.00004 (+-0.000589912)
found 4.94 (+-0.000118753) 59.8414 (+-0.116986) 9.00007 (+-0.000590103)
found 6.74 (+-0.000119129) 59.8415 (+-0.117026) 9.00009 (+-0.000590304)
found 8.18 (+-0.000118832) 59.8413 (+-0.116991) 9.00006 (+-0.000590125)
found -8.74 (+-0.000126912) 53.1928 (+-0.110395) 8.00013 (+-0.000556856)
found -4.78 (+-0.000126046) 53.1924 (+-0.110305) 8.00007 (+-0.000556404)
found -2.98 (+-0.000126182) 53.1924 (+-0.110315) 8.00007 (+-0.000556454)
found 7.1 (+-0.000135774) 46.5438 (+-0.103275) 7.00013 (+-0.000520941)
found -6.22 (+-0.000134263) 46.5431 (+-0.103134) 7.00003 (+-0.000520229)
found -3.34 (+-0.00013494) 46.5434 (+-0.103196) 7.00007 (+-0.000520544)
found -0.1 (+-0.000135253) 46.5435 (+-0.103224) 7.00008 (+-0.000520683)
found 1.34 (+-0.000146377) 39.8946 (+-0.0955918) 6.00009 (+-0.000482185)
found -1.9 (+-0.000145904) 39.8944 (+-0.0955521) 6.00006 (+-0.000481985)
found -1.54 (+-0.000146269) 39.8945 (+-0.0955816) 6.00008 (+-0.000482134)
found -1.18 (+-0.000145904) 39.8944 (+-0.0955521) 6.00006 (+-0.000481985)
found -0.46 (+-0.000145998) 39.8944 (+-0.09556) 6.00007 (+-0.000482025)
found 0.26 (+-0.000146138) 39.8944 (+-0.0955711) 6.00007 (+-0.000482081)
found 3.5 (+-0.0001458) 39.8943 (+-0.0955434) 6.00005 (+-0.000481941)
found 6.02 (+-0.000145731) 39.8943 (+-0.0955388) 6.00005 (+-0.000481918)
found 6.38 (+-0.000146528) 39.8946 (+-0.0956038) 6.0001 (+-0.000482246)
found 8.9 (+-0.000146164) 39.8944 (+-0.0955729) 6.00007 (+-0.00048209)
found 9.26 (+-0.000146164) 39.8944 (+-0.0955729) 6.00007 (+-0.00048209)
found 8.54 (+-0.00016078) 33.2456 (+-0.0872929) 5.0001 (+-0.000440324)
found 3.86 (+-0.00016078) 33.2456 (+-0.0872929) 5.0001 (+-0.000440324)
found 9.62 (+-0.000158784) 33.2454 (+-0.0871715) 5.00007 (+-0.000439711)
found -6.94 (+-0.00017913) 26.5965 (+-0.0780466) 4.00007 (+-0.000393684)
found 0.620001 (+-0.000180253) 26.5967 (+-0.0781063) 4.00011 (+-0.000393985)
found 1.7 (+-0.00017946) 26.5964 (+-0.0780601) 4.00007 (+-0.000393752)
found 2.06 (+-0.000179827) 26.5965 (+-0.0780819) 4.00009 (+-0.000393862)
found 7.82 (+-0.000180625) 26.5968 (+-0.0781281) 4.00013 (+-0.000394095)
found -5.5 (+-0.000179729) 26.5966 (+-0.0780772) 4.00009 (+-0.000393838)
found -9.46 (+-0.000209266) 19.9478 (+-0.0676927) 3.00013 (+-0.000341456)
found -5.86 (+-0.000207946) 19.9475 (+-0.0676336) 3.00007 (+-0.000341158)
found -2.62 (+-0.000207842) 19.9475 (+-0.0676298) 3.00007 (+-0.000341139)
found -0.82 (+-0.000208185) 19.9475 (+-0.0676438) 3.00008 (+-0.00034121)
found -2.26 (+-0.000207517) 19.9474 (+-0.0676151) 3.00006 (+-0.000341065)
found 3.14 (+-0.00020675) 19.9473 (+-0.0675848) 3.00005 (+-0.000340912)
found 5.66 (+-0.000256982) 13.2987 (+-0.0552926) 2.00011 (+-0.000278907)
found -3.7 (+-0.000254965) 13.2984 (+-0.0552324) 2.00006 (+-0.000278604)
found -4.06 (+-0.000252714) 13.2981 (+-0.055167) 2.00002 (+-0.000278274)
found -7.66 (+-0.00036865) 6.64989 (+-0.0391829) 1.00014 (+-0.000197647)
found 4.58 (+-0.00036798) 6.6498 (+-0.0391716) 1.00012 (+-0.00019759)
found -4.42 (+-0.000363877) 6.64944 (+-0.0391067) 1.00007 (+-0.000197263)
found 2.78 (+-0.00036507) 6.64953 (+-0.0391251) 1.00008 (+-0.000197355)
found -6.58 (+-0.000364994) 6.64949 (+-0.0391228) 1.00007 (+-0.000197344)

 
#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.