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 39.8942 6
created -9.46 19.9471 3
created -9.1 39.8942 6
created -8.74 46.5433 7
created -8.38 53.1923 8
created -8.02 26.5962 4
created -7.66 6.64904 1
created -7.3 33.2452 5
created -6.94 39.8942 6
created -6.58 59.8413 9
created -6.22 39.8942 6
created -5.86 59.8413 9
created -5.5 26.5962 4
created -5.14 46.5433 7
created -4.78 46.5433 7
created -4.42 33.2452 5
created -4.06 46.5433 7
created -3.7 66.4904 10
created -3.34 33.2452 5
created -2.98 46.5433 7
created -2.62 33.2452 5
created -2.26 59.8413 9
created -1.9 59.8413 9
created -1.54 39.8942 6
created -1.18 66.4904 10
created -0.82 19.9471 3
created -0.46 59.8413 9
created -0.1 46.5433 7
created 0.26 19.9471 3
created 0.62 26.5962 4
created 0.98 53.1923 8
created 1.34 13.2981 2
created 1.7 26.5962 4
created 2.06 33.2452 5
created 2.42 19.9471 3
created 2.78 33.2452 5
created 3.14 33.2452 5
created 3.5 19.9471 3
created 3.86 39.8942 6
created 4.22 46.5433 7
created 4.58 26.5962 4
created 4.94 33.2452 5
created 5.3 33.2452 5
created 5.66 53.1923 8
created 6.02 13.2981 2
created 6.38 46.5433 7
created 6.74 39.8942 6
created 7.1 19.9471 3
created 7.46 39.8942 6
created 7.82 59.8413 9
created 8.18 39.8942 6
created 8.54 59.8413 9
created 8.9 26.5962 4
created 9.26 26.5962 4
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 (+-1.43673e-05)
fit chi^2 = 3.0455e-06
found -3.7 (+-0.000141812) 66.4905 (+-0.154969) 10.0001 (+-0.000781698)
found -1.18 (+-0.000141529) 66.4903 (+-0.154933) 10.0001 (+-0.000781513)
found -1.9 (+-0.000149829) 59.8416 (+-0.147059) 9.0001 (+-0.000741797)
found -6.58 (+-0.0001496) 59.8415 (+-0.147031) 9.00008 (+-0.000741654)
found -5.86 (+-0.000149402) 59.8414 (+-0.147007) 9.00007 (+-0.000741536)
found -2.26 (+-0.000149736) 59.8416 (+-0.147048) 9.00009 (+-0.000741741)
found -0.46 (+-0.000149362) 59.8414 (+-0.147003) 9.00007 (+-0.000741516)
found 7.82 (+-0.0001496) 59.8415 (+-0.147031) 9.00008 (+-0.000741654)
found 8.54 (+-0.000149402) 59.8414 (+-0.147007) 9.00007 (+-0.000741536)
found -8.38 (+-0.000158681) 53.1924 (+-0.138623) 8.00007 (+-0.000699245)
found 0.98 (+-0.000158068) 53.1922 (+-0.138559) 8.00004 (+-0.00069892)
found 5.66 (+-0.000158183) 53.1922 (+-0.138571) 8.00005 (+-0.000698982)
found 9.62 (+-0.000157222) 53.1925 (+-0.138488) 8.00008 (+-0.000698565)
found -0.100001 (+-0.000169827) 46.5435 (+-0.12969) 7.00008 (+-0.000654182)
found -8.74 (+-0.000170141) 46.5436 (+-0.129718) 7.00009 (+-0.000654326)
found -5.14 (+-0.0001698) 46.5434 (+-0.129686) 7.00007 (+-0.000654162)
found -4.78 (+-0.000169931) 46.5435 (+-0.129698) 7.00008 (+-0.000654223)
found -4.06 (+-0.000170194) 46.5436 (+-0.129724) 7.0001 (+-0.000654355)
found -2.98 (+-0.000169713) 46.5434 (+-0.129677) 7.00007 (+-0.000654117)
found 4.22 (+-0.000169697) 46.5434 (+-0.129676) 7.00007 (+-0.000654111)
found 6.38 (+-0.000169354) 46.5433 (+-0.129645) 7.00005 (+-0.000653956)
found -6.22 (+-0.000184438) 39.8948 (+-0.120152) 6.00012 (+-0.000606073)
found -1.54 (+-0.000184532) 39.8948 (+-0.12016) 6.00013 (+-0.000606114)
found 8.18 (+-0.000184438) 39.8948 (+-0.120152) 6.00012 (+-0.000606073)
found -9.82 (+-0.000182869) 39.8941 (+-0.120012) 6.00002 (+-0.000605366)
found -9.1 (+-0.000183444) 39.8944 (+-0.120069) 6.00007 (+-0.000605655)
found -6.94 (+-0.000183978) 39.8946 (+-0.120113) 6.00009 (+-0.000605877)
found 3.86 (+-0.000183444) 39.8944 (+-0.120069) 6.00007 (+-0.000605655)
found 6.74 (+-0.000183444) 39.8944 (+-0.120069) 6.00007 (+-0.000605655)
found 7.46 (+-0.00018365) 39.8945 (+-0.120087) 6.00008 (+-0.000605745)
found -3.34 (+-0.000202265) 33.2457 (+-0.1097) 5.00011 (+-0.000553349)
found -7.3 (+-0.000200485) 33.2453 (+-0.109579) 5.00005 (+-0.000552739)
found -4.42 (+-0.000201912) 33.2456 (+-0.109674) 5.00009 (+-0.000553219)
found -2.62 (+-0.000202156) 33.2457 (+-0.109692) 5.00011 (+-0.000553309)
found 2.06 (+-0.000200769) 33.2453 (+-0.109594) 5.00005 (+-0.000552817)
found 2.78 (+-0.000200943) 33.2453 (+-0.109607) 5.00005 (+-0.000552878)
found 3.14 (+-0.000200943) 33.2453 (+-0.109607) 5.00005 (+-0.000552878)
found 4.94 (+-0.000201149) 33.2454 (+-0.10962) 5.00006 (+-0.000552948)
found 5.3 (+-0.000201744) 33.2455 (+-0.109662) 5.00009 (+-0.00055316)
found -8.02 (+-0.000224806) 26.5964 (+-0.0980477) 4.00006 (+-0.000494573)
found -5.5 (+-0.000226523) 26.5967 (+-0.098141) 4.00011 (+-0.000495044)
found 4.58 (+-0.00022587) 26.5965 (+-0.0981029) 4.00008 (+-0.000494852)
found 8.9 (+-0.000225949) 26.5966 (+-0.0981083) 4.00009 (+-0.000494879)
found 9.26 (+-0.000225808) 26.5965 (+-0.0980999) 4.00008 (+-0.000494837)
found 0.620001 (+-0.000225556) 26.5965 (+-0.0980861) 4.00007 (+-0.000494767)
found 1.7 (+-0.000224739) 26.5963 (+-0.09804) 4.00005 (+-0.000494534)
found -9.46 (+-0.000261581) 19.9475 (+-0.0849931) 3.00008 (+-0.000428723)
found -0.82 (+-0.000262938) 19.9478 (+-0.0850546) 3.00013 (+-0.000429033)
found 0.259999 (+-0.000261279) 19.9475 (+-0.0849803) 3.00007 (+-0.000428658)
found 2.42 (+-0.000261099) 19.9474 (+-0.0849719) 3.00007 (+-0.000428616)
found 3.5 (+-0.00026134) 19.9475 (+-0.0849825) 3.00007 (+-0.00042867)
found 7.1 (+-0.000261581) 19.9475 (+-0.0849931) 3.00008 (+-0.000428723)
found 1.34 (+-0.000321671) 13.2985 (+-0.0694365) 2.00008 (+-0.000350252)
found 6.02 (+-0.000322711) 13.2987 (+-0.0694678) 2.0001 (+-0.00035041)
found -7.66 (+-0.000457467) 6.6494 (+-0.0491383) 1.00006 (+-0.000247864)

 
#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.