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 53.1923 8
created -9.1 6.64904 1
created -8.74 6.64904 1
created -8.38 33.2452 5
created -8.02 33.2452 5
created -7.66 6.64904 1
created -7.3 33.2452 5
created -6.94 53.1923 8
created -6.58 33.2452 5
created -6.22 39.8942 6
created -5.86 26.5962 4
created -5.5 33.2452 5
created -5.14 33.2452 5
created -4.78 46.5433 7
created -4.42 33.2452 5
created -4.06 19.9471 3
created -3.7 26.5962 4
created -3.34 53.1923 8
created -2.98 66.4904 10
created -2.62 39.8942 6
created -2.26 33.2452 5
created -1.9 6.64904 1
created -1.54 19.9471 3
created -1.18 59.8413 9
created -0.82 13.2981 2
created -0.46 19.9471 3
created -0.1 26.5962 4
created 0.26 13.2981 2
created 0.62 6.64904 1
created 0.98 53.1923 8
created 1.34 33.2452 5
created 1.7 26.5962 4
created 2.06 39.8942 6
created 2.42 53.1923 8
created 2.78 53.1923 8
created 3.14 33.2452 5
created 3.5 26.5962 4
created 3.86 33.2452 5
created 4.22 13.2981 2
created 4.58 59.8413 9
created 4.94 6.64904 1
created 5.3 19.9471 3
created 5.66 53.1923 8
created 6.02 39.8942 6
created 6.38 19.9471 3
created 6.74 13.2981 2
created 7.1 59.8413 9
created 7.46 13.2981 2
created 7.82 39.8942 6
created 8.18 33.2452 5
created 8.54 39.8942 6
created 8.9 46.5433 7
created 9.26 53.1923 8
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 (+-1.73128e-05)
fit chi^2 = 3.80423e-06
found -2.98 (+-0.000158666) 66.4905 (+-0.173224) 10.0001 (+-0.000873777)
found 9.62 (+-0.000157417) 66.4907 (+-0.173084) 10.0001 (+-0.000873075)
found -1.18 (+-0.000166318) 59.8411 (+-0.164226) 9.00003 (+-0.000828388)
found 4.58 (+-0.00016592) 59.8411 (+-0.164182) 9.00002 (+-0.000828169)
found 7.1 (+-0.00016615) 59.8411 (+-0.164207) 9.00003 (+-0.000828293)
found 2.78 (+-0.000177573) 53.1925 (+-0.154956) 8.00009 (+-0.000781629)
found -9.46 (+-0.000176406) 53.1922 (+-0.154835) 8.00003 (+-0.000781021)
found -6.94 (+-0.000177262) 53.1924 (+-0.154922) 8.00007 (+-0.000781457)
found -3.34 (+-0.00017761) 53.1926 (+-0.154961) 8.00009 (+-0.000781655)
found 0.98 (+-0.000176534) 53.1922 (+-0.154849) 8.00004 (+-0.00078109)
found 2.42 (+-0.000177688) 53.1926 (+-0.154968) 8.00009 (+-0.000781691)
found 5.66 (+-0.000177094) 53.1923 (+-0.154904) 8.00006 (+-0.000781371)
found 9.26 (+-0.000177959) 53.1927 (+-0.154998) 8.00012 (+-0.000781844)
found -4.78 (+-0.000189679) 46.5434 (+-0.144933) 7.00007 (+-0.000731071)
found 8.9 (+-0.000190158) 46.5436 (+-0.144979) 7.00009 (+-0.000731304)
found -2.62 (+-0.000205725) 39.8946 (+-0.134253) 6.0001 (+-0.000677201)
found 6.02 (+-0.000205145) 39.8944 (+-0.134205) 6.00007 (+-0.000676959)
found -6.22 (+-0.000204943) 39.8944 (+-0.134187) 6.00006 (+-0.000676868)
found 2.06 (+-0.000205342) 39.8945 (+-0.134221) 6.00008 (+-0.000677038)
found 7.82 (+-0.000204504) 39.8943 (+-0.134153) 6.00005 (+-0.000676695)
found 8.54 (+-0.00020539) 39.8945 (+-0.134224) 6.00008 (+-0.000677054)
found -6.58 (+-0.000225652) 33.2456 (+-0.122576) 5.00009 (+-0.000618298)
found 1.34 (+-0.000225281) 33.2455 (+-0.12255) 5.00008 (+-0.000618169)
found 3.14 (+-0.000225281) 33.2455 (+-0.12255) 5.00008 (+-0.000618169)
found -8.38 (+-0.000223901) 33.2452 (+-0.122458) 5.00004 (+-0.000617704)
found -8.02 (+-0.000223901) 33.2452 (+-0.122458) 5.00004 (+-0.000617704)
found -7.3 (+-0.000224363) 33.2454 (+-0.122491) 5.00006 (+-0.000617873)
found -5.5 (+-0.000224814) 33.2454 (+-0.122517) 5.00006 (+-0.000618)
found -5.14 (+-0.000225337) 33.2455 (+-0.122553) 5.00008 (+-0.000618185)
found -4.42 (+-0.000224909) 33.2454 (+-0.122524) 5.00007 (+-0.000618039)
found -2.26 (+-0.000224071) 33.2453 (+-0.12247) 5.00005 (+-0.000617765)
found 3.86 (+-0.000224103) 33.2452 (+-0.122469) 5.00004 (+-0.00061776)
found 8.18 (+-0.000225355) 33.2455 (+-0.122554) 5.00008 (+-0.000618191)
found -5.86 (+-0.000252255) 26.5965 (+-0.109633) 4.00007 (+-0.000553013)
found 1.7 (+-0.000252255) 26.5965 (+-0.109633) 4.00007 (+-0.000553013)
found 3.5 (+-0.000252045) 26.5964 (+-0.109621) 4.00007 (+-0.000552952)
found -9.82 (+-0.000251738) 26.5963 (+-0.109598) 4.00005 (+-0.000552833)
found -3.7 (+-0.000252091) 26.5965 (+-0.109625) 4.00007 (+-0.000552974)
found -0.1 (+-0.000250665) 26.5962 (+-0.109545) 4.00003 (+-0.000552569)
found -4.06 (+-0.00029151) 19.9474 (+-0.0949551) 3.00006 (+-0.000478974)
found 6.38 (+-0.000290966) 19.9473 (+-0.0949335) 3.00005 (+-0.000478864)
found -1.54 (+-0.000290987) 19.9474 (+-0.0949391) 3.00007 (+-0.000478893)
found -0.46 (+-0.000290398) 19.9472 (+-0.0949084) 3.00004 (+-0.000478738)
found 5.3 (+-0.000290789) 19.9474 (+-0.0949299) 3.00006 (+-0.000478846)
found -0.820002 (+-0.000359276) 13.2985 (+-0.0775994) 2.00008 (+-0.000391428)
found 7.46 (+-0.000360618) 13.2987 (+-0.0776388) 2.0001 (+-0.000391627)
found 0.259999 (+-0.000356016) 13.2982 (+-0.0775038) 2.00003 (+-0.000390946)
found 4.22 (+-0.000360234) 13.2986 (+-0.0776273) 2.00009 (+-0.000391568)
found 6.74 (+-0.000359276) 13.2985 (+-0.0775994) 2.00008 (+-0.000391428)
found -9.1 (+-0.000509322) 6.6494 (+-0.0548942) 1.00006 (+-0.000276898)
found 4.94 (+-0.000512667) 6.64954 (+-0.0549434) 1.00008 (+-0.000277146)
found -7.66 (+-0.000512064) 6.64944 (+-0.0549315) 1.00007 (+-0.000277086)
found -1.9 (+-0.000510361) 6.64935 (+-0.0549049) 1.00005 (+-0.000276952)
found 0.620004 (+-0.000510992) 6.64945 (+-0.0549175) 1.00007 (+-0.000277016)
found -8.74 (+-0.000507542) 6.64927 (+-0.0548642) 1.00004 (+-0.000276747)

 
#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.