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 26.5962 4
created -9.46 66.4904 10
created -9.1 19.9471 3
created -8.74 53.1923 8
created -8.38 13.2981 2
created -8.02 66.4904 10
created -7.66 33.2452 5
created -7.3 26.5962 4
created -6.94 59.8413 9
created -6.58 19.9471 3
created -6.22 46.5433 7
created -5.86 59.8413 9
created -5.5 46.5433 7
created -5.14 13.2981 2
created -4.78 19.9471 3
created -4.42 53.1923 8
created -4.06 6.64904 1
created -3.7 46.5433 7
created -3.34 26.5962 4
created -2.98 46.5433 7
created -2.62 53.1923 8
created -2.26 26.5962 4
created -1.9 66.4904 10
created -1.54 6.64904 1
created -1.18 39.8942 6
created -0.82 33.2452 5
created -0.46 46.5433 7
created -0.1 26.5962 4
created 0.26 53.1923 8
created 0.62 26.5962 4
created 0.98 6.64904 1
created 1.34 6.64904 1
created 1.7 66.4904 10
created 2.06 66.4904 10
created 2.42 53.1923 8
created 2.78 53.1923 8
created 3.14 33.2452 5
created 3.5 6.64904 1
created 3.86 59.8413 9
created 4.22 59.8413 9
created 4.58 53.1923 8
created 4.94 39.8942 6
created 5.3 13.2981 2
created 5.66 59.8413 9
created 6.02 46.5433 7
created 6.38 66.4904 10
created 6.74 19.9471 3
created 7.1 33.2452 5
created 7.46 26.5962 4
created 7.82 66.4904 10
created 8.18 66.4904 10
created 8.54 13.2981 2
created 8.9 26.5962 4
created 9.26 66.4904 10
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 (+-1.42041e-05)
fit chi^2 = 3.06208e-06
found -9.46 (+-0.000141734) 66.4902 (+-0.15533) 10 (+-0.000783519)
found -8.02 (+-0.000141692) 66.4902 (+-0.155326) 10 (+-0.000783496)
found -1.9 (+-0.000141408) 66.4901 (+-0.155291) 10 (+-0.000783323)
found 1.7 (+-0.000141852) 66.4904 (+-0.155352) 10.0001 (+-0.000783627)
found 2.06 (+-0.000142621) 66.4907 (+-0.155448) 10.0001 (+-0.000784113)
found 6.38 (+-0.000141989) 66.4904 (+-0.155364) 10.0001 (+-0.000783689)
found 7.82 (+-0.000142294) 66.4905 (+-0.155405) 10.0001 (+-0.000783895)
found 8.18 (+-0.000142042) 66.4905 (+-0.155374) 10.0001 (+-0.000783738)
found 9.26 (+-0.00014217) 66.4905 (+-0.155388) 10.0001 (+-0.000783809)
found 4.22 (+-0.000150396) 59.8417 (+-0.147479) 9.00011 (+-0.000743913)
found -6.94 (+-0.000149489) 59.8412 (+-0.147369) 9.00005 (+-0.000743363)
found -5.86 (+-0.000150173) 59.8415 (+-0.147451) 9.00009 (+-0.000743773)
found 3.86 (+-0.000149552) 59.8414 (+-0.147382) 9.00007 (+-0.000743427)
found 5.66 (+-0.000149616) 59.8413 (+-0.147386) 9.00006 (+-0.000743447)
found 2.42 (+-0.000159745) 53.1927 (+-0.139069) 8.00012 (+-0.000701495)
found 2.78 (+-0.000159314) 53.1925 (+-0.139022) 8.00009 (+-0.000701255)
found 4.58 (+-0.000159495) 53.1926 (+-0.139042) 8.0001 (+-0.000701355)
found 9.62 (+-0.000158182) 53.1927 (+-0.138925) 8.00012 (+-0.000700765)
found -8.74 (+-0.000158362) 53.1922 (+-0.138922) 8.00003 (+-0.00070075)
found -4.42 (+-0.000158132) 53.1921 (+-0.138899) 8.00003 (+-0.000700638)
found -2.62 (+-0.000159113) 53.1924 (+-0.139) 8.00007 (+-0.000701146)
found 0.26 (+-0.000158802) 53.1923 (+-0.138967) 8.00005 (+-0.000700977)
found -5.5 (+-0.000170098) 46.5434 (+-0.130025) 7.00007 (+-0.000655875)
found 6.02 (+-0.000171061) 46.5438 (+-0.130116) 7.00013 (+-0.000656332)
found -6.22 (+-0.000170289) 46.5435 (+-0.130042) 7.00008 (+-0.00065596)
found -3.7 (+-0.000169309) 46.5432 (+-0.129952) 7.00003 (+-0.000655505)
found -2.98 (+-0.000170356) 46.5435 (+-0.130048) 7.00008 (+-0.000655987)
found -0.46 (+-0.000170044) 46.5433 (+-0.130017) 7.00006 (+-0.000655834)
found 4.94 (+-0.000183831) 39.8944 (+-0.120388) 6.00007 (+-0.000607264)
found -1.18 (+-0.000183174) 39.8942 (+-0.120336) 6.00004 (+-0.000607)
found -7.66 (+-0.000202341) 33.2456 (+-0.109965) 5.00009 (+-0.000554687)
found 3.14 (+-0.000201292) 33.2454 (+-0.109896) 5.00006 (+-0.000554338)
found -0.82 (+-0.000202322) 33.2455 (+-0.109962) 5.00009 (+-0.000554673)
found 7.1 (+-0.000201315) 33.2453 (+-0.109892) 5.00005 (+-0.00055432)
found -7.3 (+-0.000226779) 26.5966 (+-0.0983871) 4.00009 (+-0.000496286)
found -3.34 (+-0.000226843) 26.5966 (+-0.0983902) 4.00009 (+-0.000496301)
found -2.26 (+-0.000227426) 26.5968 (+-0.0984248) 4.00012 (+-0.000496476)
found -0.0999999 (+-0.000226997) 26.5966 (+-0.0983993) 4.0001 (+-0.000496347)
found 0.619999 (+-0.000225417) 26.5964 (+-0.0983143) 4.00006 (+-0.000495918)
found 7.46 (+-0.000226911) 26.5966 (+-0.0983951) 4.0001 (+-0.000496326)
found -9.82 (+-0.000226122) 26.5964 (+-0.0983442) 4.00007 (+-0.000496069)
found 8.9 (+-0.000226125) 26.5965 (+-0.0983526) 4.00008 (+-0.000496111)
found -9.1 (+-0.00026347) 19.9478 (+-0.0852775) 3.00012 (+-0.000430158)
found -6.58 (+-0.000263104) 19.9477 (+-0.0852608) 3.00011 (+-0.000430073)
found 6.74 (+-0.00026281) 19.9476 (+-0.0852482) 3.0001 (+-0.00043001)
found -4.78 (+-0.000261454) 19.9474 (+-0.0851901) 3.00007 (+-0.000429717)
found 8.54 (+-0.000323031) 13.2986 (+-0.0696409) 2.00009 (+-0.000351283)
found -8.38 (+-0.000324358) 13.2988 (+-0.069681) 2.00012 (+-0.000351486)
found -5.14 (+-0.000321808) 13.2984 (+-0.0696032) 2.00007 (+-0.000351093)
found 5.3 (+-0.000323536) 13.2987 (+-0.0696553) 2.0001 (+-0.000351356)
found -4.06 (+-0.000462211) 6.64967 (+-0.0493287) 1.0001 (+-0.000248824)
found -1.54 (+-0.000462533) 6.64971 (+-0.0493345) 1.00011 (+-0.000248854)
found 3.5 (+-0.000461499) 6.64962 (+-0.0493175) 1.00009 (+-0.000248768)
found 0.979998 (+-0.000454672) 6.64922 (+-0.0492116) 1.00003 (+-0.000248234)
found 1.34001 (+-0.000457793) 6.64949 (+-0.0492642) 1.00008 (+-0.000248499)

 
#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.