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 33.2452 5
created -9.46 53.1923 8
created -9.1 53.1923 8
created -8.74 39.8942 6
created -8.38 46.5433 7
created -8.02 53.1923 8
created -7.66 46.5433 7
created -7.3 66.4904 10
created -6.94 19.9471 3
created -6.58 26.5962 4
created -6.22 59.8413 9
created -5.86 59.8413 9
created -5.5 66.4904 10
created -5.14 39.8942 6
created -4.78 19.9471 3
created -4.42 6.64904 1
created -4.06 39.8942 6
created -3.7 33.2452 5
created -3.34 6.64904 1
created -2.98 59.8413 9
created -2.62 46.5433 7
created -2.26 33.2452 5
created -1.9 66.4904 10
created -1.54 19.9471 3
created -1.18 46.5433 7
created -0.82 33.2452 5
created -0.46 46.5433 7
created -0.1 19.9471 3
created 0.26 6.64904 1
created 0.62 13.2981 2
created 0.98 6.64904 1
created 1.34 19.9471 3
created 1.7 6.64904 1
created 2.06 6.64904 1
created 2.42 26.5962 4
created 2.78 13.2981 2
created 3.14 59.8413 9
created 3.5 19.9471 3
created 3.86 6.64904 1
created 4.22 53.1923 8
created 4.58 33.2452 5
created 4.94 13.2981 2
created 5.3 46.5433 7
created 5.66 33.2452 5
created 6.02 19.9471 3
created 6.38 46.5433 7
created 6.74 53.1923 8
created 7.1 53.1923 8
created 7.46 39.8942 6
created 7.82 39.8942 6
created 8.18 19.9471 3
created 8.54 46.5433 7
created 8.9 39.8942 6
created 9.26 33.2452 5
created 9.62 39.8942 6
the total number of created peaks = 55 with sigma = 0.06
the total number of found peaks = 55 with sigma = 0.0600004 (+-1.30726e-05)
fit chi^2 = 2.29394e-06
found -7.3 (+-0.000122896) 66.4904 (+-0.134472) 10.0001 (+-0.000678307)
found -5.5 (+-0.000123264) 66.4906 (+-0.134521) 10.0001 (+-0.000678552)
found -1.9 (+-0.000122758) 66.4903 (+-0.134454) 10.0001 (+-0.000678214)
found -5.86 (+-0.00013029) 59.8418 (+-0.127662) 9.00013 (+-0.000643954)
found -6.22 (+-0.000129862) 59.8415 (+-0.12761) 9.00009 (+-0.000643691)
found -2.98 (+-0.000129317) 59.8413 (+-0.127548) 9.00005 (+-0.000643379)
found 3.14 (+-0.000129151) 59.8411 (+-0.127526) 9.00003 (+-0.000643267)
found -9.1 (+-0.00013798) 53.1926 (+-0.120337) 8.00009 (+-0.000607006)
found 7.1 (+-0.00013798) 53.1926 (+-0.120337) 8.00009 (+-0.000607006)
found -9.46 (+-0.000137891) 53.1925 (+-0.120328) 8.00009 (+-0.000606958)
found -8.02 (+-0.000137987) 53.1926 (+-0.120338) 8.00009 (+-0.000607009)
found 4.22 (+-0.000137084) 53.1922 (+-0.120245) 8.00004 (+-0.000606539)
found 6.74 (+-0.00013806) 53.1926 (+-0.120346) 8.0001 (+-0.00060705)
found -7.66 (+-0.000147982) 46.5437 (+-0.112612) 7.00012 (+-0.000568037)
found -2.62 (+-0.000147638) 46.5436 (+-0.112578) 7.00009 (+-0.000567868)
found -8.38 (+-0.000147663) 46.5436 (+-0.11258) 7.00009 (+-0.000567879)
found -1.18 (+-0.000147045) 46.5433 (+-0.112522) 7.00005 (+-0.000567583)
found -0.46 (+-0.000147045) 46.5433 (+-0.112522) 7.00005 (+-0.000567583)
found 5.3 (+-0.000146881) 46.5433 (+-0.112507) 7.00005 (+-0.000567509)
found 6.38 (+-0.000147315) 46.5434 (+-0.112548) 7.00007 (+-0.000567715)
found 8.54 (+-0.000147144) 46.5433 (+-0.112531) 7.00006 (+-0.000567631)
found -8.74 (+-0.000159803) 39.8946 (+-0.104255) 6.0001 (+-0.000525884)
found -5.14 (+-0.000159467) 39.8945 (+-0.104229) 6.00009 (+-0.000525752)
found 7.46 (+-0.0001597) 39.8946 (+-0.104246) 6.00009 (+-0.000525841)
found -4.06 (+-0.000158542) 39.8942 (+-0.104154) 6.00004 (+-0.000525377)
found 7.82 (+-0.000159106) 39.8944 (+-0.104197) 6.00006 (+-0.000525594)
found 8.9 (+-0.000159491) 39.8945 (+-0.104229) 6.00008 (+-0.000525752)
found 9.62 (+-0.000157834) 39.8944 (+-0.104112) 6.00007 (+-0.000525162)
found 4.58 (+-0.000174534) 33.2454 (+-0.0951372) 5.00007 (+-0.000479892)
found -9.82 (+-0.000174651) 33.2453 (+-0.0951367) 5.00005 (+-0.00047989)
found -3.7 (+-0.000173998) 33.2453 (+-0.0951016) 5.00005 (+-0.000479713)
found -2.26 (+-0.000175543) 33.2457 (+-0.0952067) 5.00011 (+-0.000480243)
found -0.82 (+-0.000175236) 33.2456 (+-0.0951843) 5.00009 (+-0.00048013)
found 5.66 (+-0.000174648) 33.2454 (+-0.0951437) 5.00007 (+-0.000479925)
found 9.26 (+-0.000174995) 33.2455 (+-0.0951671) 5.00008 (+-0.000480043)
found -6.58 (+-0.000195878) 26.5965 (+-0.0851347) 4.00008 (+-0.000429437)
found 2.42 (+-0.000194008) 26.5961 (+-0.0850317) 4.00002 (+-0.000428918)
found -6.94 (+-0.000227229) 19.9476 (+-0.0737746) 3.00009 (+-0.000372135)
found -4.78 (+-0.000225456) 19.9473 (+-0.0736997) 3.00005 (+-0.000371757)
found -1.54 (+-0.00022787) 19.9477 (+-0.0738025) 3.00011 (+-0.000372276)
found -0.100001 (+-0.00022564) 19.9473 (+-0.0737081) 3.00005 (+-0.000371799)
found 3.5 (+-0.00022596) 19.9474 (+-0.073723) 3.00007 (+-0.000371874)
found 6.02 (+-0.000226999) 19.9475 (+-0.0737633) 3.00008 (+-0.000372078)
found 8.18 (+-0.000227209) 19.9476 (+-0.0737725) 3.00009 (+-0.000372124)
found 1.34 (+-0.000223922) 19.9471 (+-0.0736355) 3.00001 (+-0.000371433)
found 2.78 (+-0.000279391) 13.2986 (+-0.0602698) 2.00009 (+-0.000304013)
found 4.94 (+-0.000279275) 13.2985 (+-0.0602654) 2.00008 (+-0.000303991)
found 0.62 (+-0.000274896) 13.2981 (+-0.0601399) 2.00001 (+-0.000303358)
found -3.34 (+-0.000399441) 6.64962 (+-0.0426858) 1.00009 (+-0.000215316)
found 3.86 (+-0.000397715) 6.64949 (+-0.0426585) 1.00007 (+-0.000215179)
found -4.42 (+-0.000396831) 6.6494 (+-0.0426437) 1.00006 (+-0.000215104)
found 0.259999 (+-0.000394104) 6.64922 (+-0.0426012) 1.00003 (+-0.000214889)
found 1.7 (+-0.000392833) 6.64917 (+-0.0425831) 1.00003 (+-0.000214798)
found 0.980001 (+-0.000394104) 6.64922 (+-0.0426012) 1.00003 (+-0.000214889)
found 2.06 (+-0.000393533) 6.64922 (+-0.0425941) 1.00003 (+-0.000214854)

 
#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.