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 33.2452 5
created -9.1 59.8413 9
created -8.74 39.8942 6
created -8.38 66.4904 10
created -8.02 13.2981 2
created -7.66 39.8942 6
created -7.3 6.64904 1
created -6.94 39.8942 6
created -6.58 6.64904 1
created -6.22 46.5433 7
created -5.86 33.2452 5
created -5.5 6.64904 1
created -5.14 6.64904 1
created -4.78 26.5962 4
created -4.42 53.1923 8
created -4.06 39.8942 6
created -3.7 66.4904 10
created -3.34 39.8942 6
created -2.98 6.64904 1
created -2.62 46.5433 7
created -2.26 46.5433 7
created -1.9 13.2981 2
created -1.54 59.8413 9
created -1.18 26.5962 4
created -0.82 53.1923 8
created -0.46 6.64904 1
created -0.1 46.5433 7
created 0.26 6.64904 1
created 0.62 46.5433 7
created 0.98 19.9471 3
created 1.34 26.5962 4
created 1.7 13.2981 2
created 2.06 53.1923 8
created 2.42 59.8413 9
created 2.78 19.9471 3
created 3.14 26.5962 4
created 3.5 53.1923 8
created 3.86 39.8942 6
created 4.22 33.2452 5
created 4.58 19.9471 3
created 4.94 59.8413 9
created 5.3 13.2981 2
created 5.66 6.64904 1
created 6.02 66.4904 10
created 6.38 59.8413 9
created 6.74 46.5433 7
created 7.1 39.8942 6
created 7.46 53.1923 8
created 7.82 26.5962 4
created 8.18 19.9471 3
created 8.54 6.64904 1
created 8.9 46.5433 7
created 9.26 6.64904 1
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 (+-1.52143e-05)
fit chi^2 = 3.06404e-06
found -8.38 (+-0.00014182) 66.4903 (+-0.155387) 10.0001 (+-0.000783802)
found -3.7 (+-0.000142251) 66.4905 (+-0.155441) 10.0001 (+-0.000784078)
found 6.02 (+-0.000141838) 66.4904 (+-0.155393) 10.0001 (+-0.000783835)
found 2.42 (+-0.000149892) 59.8414 (+-0.147459) 9.00007 (+-0.000743817)
found 6.38 (+-0.000150433) 59.8417 (+-0.147524) 9.00011 (+-0.000744144)
found -9.82 (+-0.000149817) 59.8412 (+-0.147437) 9.00003 (+-0.000743702)
found -9.1 (+-0.000149962) 59.8414 (+-0.147466) 9.00007 (+-0.000743852)
found -1.54 (+-0.000149385) 59.8412 (+-0.1474) 9.00004 (+-0.000743514)
found 4.94 (+-0.000149263) 59.8411 (+-0.147385) 9.00003 (+-0.000743443)
found -4.42 (+-0.000159071) 53.1924 (+-0.139034) 8.00007 (+-0.000701318)
found -0.82 (+-0.000158317) 53.1922 (+-0.138958) 8.00003 (+-0.000700933)
found 2.06 (+-0.000159018) 53.1924 (+-0.139032) 8.00007 (+-0.000701304)
found 3.5 (+-0.000159071) 53.1924 (+-0.139034) 8.00007 (+-0.000701318)
found 7.46 (+-0.000159071) 53.1924 (+-0.139034) 8.00007 (+-0.000701318)
found 9.62 (+-0.000157175) 53.1923 (+-0.138856) 8.00006 (+-0.00070042)
found 6.74 (+-0.000170746) 46.5436 (+-0.130121) 7.0001 (+-0.000656358)
found -6.22 (+-0.000169492) 46.5432 (+-0.130006) 7.00004 (+-0.000655776)
found -2.62 (+-0.000169708) 46.5433 (+-0.130027) 7.00005 (+-0.000655882)
found -2.26 (+-0.000169971) 46.5433 (+-0.130049) 7.00006 (+-0.000655993)
found -0.1 (+-0.000168765) 46.543 (+-0.12994) 7.00001 (+-0.000655447)
found 0.62 (+-0.000169211) 46.5431 (+-0.129979) 7.00003 (+-0.000655643)
found 8.9 (+-0.000168765) 46.543 (+-0.12994) 7.00001 (+-0.000655447)
found -8.74 (+-0.000185092) 39.8948 (+-0.120525) 6.00013 (+-0.000607955)
found -4.06 (+-0.000184992) 39.8948 (+-0.120517) 6.00012 (+-0.000607912)
found -3.34 (+-0.000183776) 39.8944 (+-0.120421) 6.00007 (+-0.00060743)
found 3.86 (+-0.000184437) 39.8945 (+-0.12047) 6.00009 (+-0.000607674)
found -7.66 (+-0.000182695) 39.8941 (+-0.120331) 6.00002 (+-0.000606977)
found -6.94 (+-0.000182398) 39.894 (+-0.120309) 6.00001 (+-0.000606866)
found 7.1 (+-0.000184689) 39.8946 (+-0.120491) 6.0001 (+-0.00060778)
found -9.46 (+-0.000203016) 33.2458 (+-0.110043) 5.00012 (+-0.000555079)
found -5.86 (+-0.000201231) 33.2453 (+-0.109922) 5.00005 (+-0.000554468)
found 4.22 (+-0.000201708) 33.2454 (+-0.10995) 5.00006 (+-0.000554613)
found -1.18 (+-0.000227366) 26.5967 (+-0.0984483) 4.00011 (+-0.000496594)
found 7.82 (+-0.000226241) 26.5965 (+-0.0983842) 4.00007 (+-0.00049627)
found -4.78 (+-0.000225489) 26.5964 (+-0.0983456) 4.00006 (+-0.000496076)
found 1.34 (+-0.000224961) 26.5962 (+-0.0983121) 4.00003 (+-0.000495907)
found 3.14 (+-0.000226241) 26.5965 (+-0.0983842) 4.00007 (+-0.00049627)
found 0.979999 (+-0.000262073) 19.9475 (+-0.0852385) 3.00007 (+-0.000429961)
found 2.78 (+-0.000262449) 19.9476 (+-0.0852557) 3.00009 (+-0.000430048)
found 4.58 (+-0.000262726) 19.9476 (+-0.0852676) 3.00009 (+-0.000430108)
found 8.18 (+-0.000260059) 19.9472 (+-0.0851545) 3.00003 (+-0.000429537)
found -8.02 (+-0.000323874) 13.2987 (+-0.0696851) 2.00011 (+-0.000351506)
found 5.3 (+-0.00032104) 13.2984 (+-0.0696044) 2.00007 (+-0.000351099)
found -1.9 (+-0.000323946) 13.2987 (+-0.069687) 2.00011 (+-0.000351516)
found 1.7 (+-0.000322649) 13.2985 (+-0.0696475) 2.00008 (+-0.000351317)
found -0.460001 (+-0.000462358) 6.64967 (+-0.0493444) 1.0001 (+-0.000248904)
found 0.26 (+-0.000461864) 6.64962 (+-0.0493362) 1.00009 (+-0.000248862)
found 9.26 (+-0.000462358) 6.64967 (+-0.0493444) 1.0001 (+-0.000248904)
found -6.58 (+-0.000461318) 6.64958 (+-0.0493273) 1.00009 (+-0.000248817)
found -2.98 (+-0.000461318) 6.64958 (+-0.0493273) 1.00009 (+-0.000248817)
found -7.3 (+-0.000460774) 6.64953 (+-0.0493183) 1.00008 (+-0.000248772)
found -5.5 (+-0.000455497) 6.64926 (+-0.0492383) 1.00004 (+-0.000248368)
found 8.54 (+-0.000459165) 6.64944 (+-0.0492935) 1.00007 (+-0.000248647)
found 5.66 (+-0.000459445) 6.64954 (+-0.0493009) 1.00008 (+-0.000248684)
found -5.14 (+-0.000454817) 6.64922 (+-0.0492273) 1.00003 (+-0.000248313)

 
#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.