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 33.2452 5
created -9.1 6.64904 1
created -8.74 39.8942 6
created -8.38 13.2981 2
created -8.02 53.1923 8
created -7.66 19.9471 3
created -7.3 66.4904 10
created -6.94 6.64904 1
created -6.58 19.9471 3
created -6.22 19.9471 3
created -5.86 59.8413 9
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 46.5433 7
created -3.7 26.5962 4
created -3.34 26.5962 4
created -2.98 19.9471 3
created -2.62 53.1923 8
created -2.26 66.4904 10
created -1.9 6.64904 1
created -1.54 53.1923 8
created -1.18 39.8942 6
created -0.82 19.9471 3
created -0.46 46.5433 7
created -0.1 33.2452 5
created 0.26 66.4904 10
created 0.62 46.5433 7
created 0.98 33.2452 5
created 1.34 6.64904 1
created 1.7 6.64904 1
created 2.06 59.8413 9
created 2.42 6.64904 1
created 2.78 53.1923 8
created 3.14 46.5433 7
created 3.5 53.1923 8
created 3.86 46.5433 7
created 4.22 26.5962 4
created 4.58 33.2452 5
created 4.94 66.4904 10
created 5.3 6.64904 1
created 5.66 59.8413 9
created 6.02 26.5962 4
created 6.38 26.5962 4
created 6.74 6.64904 1
created 7.1 53.1923 8
created 7.46 26.5962 4
created 7.82 53.1923 8
created 8.18 13.2981 2
created 8.54 19.9471 3
created 8.9 59.8413 9
created 9.26 39.8942 6
created 9.62 66.4904 10
the total number of created peaks = 55 with sigma = 0.06
the total number of found peaks = 55 with sigma = 0.0600004 (+-1.66253e-05)
fit chi^2 = 3.82385e-06
found -9.82 (+-0.000158722) 66.4902 (+-0.173608) 10 (+-0.000875716)
found -7.3 (+-0.000157898) 66.4901 (+-0.17352) 10 (+-0.000875271)
found -2.26 (+-0.000158381) 66.4903 (+-0.173584) 10.0001 (+-0.000875594)
found 0.26 (+-0.000158903) 66.4905 (+-0.173647) 10.0001 (+-0.000875911)
found 4.94 (+-0.000158127) 66.4902 (+-0.17355) 10 (+-0.000875421)
found 9.62 (+-0.000157664) 66.4906 (+-0.173508) 10.0001 (+-0.000875213)
found -5.86 (+-0.000166515) 59.8411 (+-0.164624) 9.00002 (+-0.000830397)
found 2.06 (+-0.000166118) 59.841 (+-0.16458) 9.00001 (+-0.000830178)
found 5.66 (+-0.000166651) 59.8412 (+-0.16464) 9.00003 (+-0.000830477)
found 8.9 (+-0.000167271) 59.8413 (+-0.164709) 9.00006 (+-0.000830829)
found -8.02 (+-0.000176968) 53.1922 (+-0.155243) 8.00003 (+-0.000783077)
found -4.78 (+-0.000178052) 53.1925 (+-0.155357) 8.00009 (+-0.000783652)
found -2.62 (+-0.000177914) 53.1925 (+-0.155344) 8.00009 (+-0.000783589)
found -1.54 (+-0.000177102) 53.1923 (+-0.15526) 8.00005 (+-0.000783164)
found 2.78 (+-0.000177204) 53.1923 (+-0.155271) 8.00005 (+-0.000783221)
found 3.5 (+-0.000178155) 53.1926 (+-0.155368) 8.00009 (+-0.000783709)
found 7.1 (+-0.00017686) 53.1922 (+-0.155234) 8.00003 (+-0.000783032)
found 7.82 (+-0.000177119) 53.1922 (+-0.155258) 8.00004 (+-0.000783156)
found -4.42 (+-0.000190764) 46.5436 (+-0.145363) 7.0001 (+-0.000733244)
found 0.62 (+-0.000190706) 46.5436 (+-0.145359) 7.0001 (+-0.00073322)
found 3.14 (+-0.00019087) 46.5437 (+-0.145374) 7.00011 (+-0.000733297)
found 3.86 (+-0.000190371) 46.5435 (+-0.145326) 7.00008 (+-0.000733056)
found -4.06 (+-0.000190265) 46.5434 (+-0.145316) 7.00007 (+-0.000733003)
found -0.46 (+-0.00018985) 46.5433 (+-0.145276) 7.00005 (+-0.000732805)
found -1.18 (+-0.000205673) 39.8944 (+-0.134551) 6.00007 (+-0.000678702)
found 9.26 (+-0.000206772) 39.8948 (+-0.134642) 6.00013 (+-0.000679164)
found -8.74 (+-0.000204094) 39.8941 (+-0.134426) 6.00002 (+-0.000678072)
found -5.14 (+-0.000205089) 39.8944 (+-0.134507) 6.00006 (+-0.000678484)
found -9.46 (+-0.000225189) 33.2455 (+-0.122825) 5.00007 (+-0.000619558)
found -0.0999996 (+-0.000226643) 33.2457 (+-0.122921) 5.00011 (+-0.00062004)
found 0.979999 (+-0.000224801) 33.2453 (+-0.122797) 5.00005 (+-0.000619412)
found 4.58 (+-0.000226113) 33.2456 (+-0.122884) 5.00009 (+-0.000619854)
found -3.7 (+-0.000252852) 26.5965 (+-0.109913) 4.00007 (+-0.000554425)
found -3.34 (+-0.000251936) 26.5963 (+-0.109861) 4.00005 (+-0.000554163)
found 4.22 (+-0.000253093) 26.5965 (+-0.109927) 4.00008 (+-0.000554493)
found 6.02 (+-0.000253181) 26.5966 (+-0.109933) 4.00009 (+-0.000554524)
found 6.38 (+-0.000251104) 26.5962 (+-0.109818) 4.00003 (+-0.000553946)
found 7.46 (+-0.000253839) 26.5967 (+-0.10997) 4.00011 (+-0.000554711)
found -7.66 (+-0.000294424) 19.9478 (+-0.0952963) 3.00012 (+-0.000480695)
found -2.98 (+-0.000292988) 19.9475 (+-0.0952323) 3.00008 (+-0.000480372)
found -0.82 (+-0.000293349) 19.9476 (+-0.0952476) 3.00009 (+-0.000480449)
found -6.58 (+-0.000290164) 19.9472 (+-0.0951133) 3.00003 (+-0.000479771)
found -6.22 (+-0.000292824) 19.9475 (+-0.0952263) 3.00008 (+-0.000480342)
found 8.54 (+-0.00029237) 19.9475 (+-0.095208) 3.00007 (+-0.000480249)
found -8.38 (+-0.000361263) 13.2986 (+-0.0778298) 2.00009 (+-0.00039259)
found 8.18 (+-0.000359921) 13.2985 (+-0.0777902) 2.00007 (+-0.00039239)
found -1.9 (+-0.000518045) 6.6498 (+-0.0551497) 1.00012 (+-0.000278187)
found 5.3 (+-0.000518556) 6.64985 (+-0.0551582) 1.00013 (+-0.00027823)
found -6.94 (+-0.000514447) 6.64958 (+-0.0550928) 1.00009 (+-0.0002779)
found 2.42 (+-0.000517575) 6.64976 (+-0.0551417) 1.00012 (+-0.000278147)
found -5.5 (+-0.000516406) 6.64967 (+-0.0551226) 1.0001 (+-0.00027805)
found -9.1 (+-0.000514062) 6.64949 (+-0.0550839) 1.00007 (+-0.000277855)
found 1.34 (+-0.000508849) 6.64927 (+-0.0550055) 1.00004 (+-0.000277459)
found 6.74 (+-0.000514427) 6.64953 (+-0.0550907) 1.00008 (+-0.000277889)
found 1.7 (+-0.000511123) 6.64945 (+-0.055044) 1.00007 (+-0.000277654)

 
#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.