Logo ROOT   6.16/01
Reference Guide
FitAwmi.C File Reference
Tutorials » Spectrum tutorials

Detailed Description

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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 -9.7 31.9154 8
created -9.1 19.9471 5
created -8.5 39.8942 10
created -7.9 23.9365 6
created -7.3 27.926 7
created -6.7 3.98942 1
created -6.1 7.97885 2
created -5.5 31.9154 8
created -4.9 35.9048 9
created -4.3 23.9365 6
created -3.7 11.9683 3
created -3.1 11.9683 3
created -2.5 31.9154 8
created -1.9 3.98942 1
created -1.3 3.98942 1
created -0.7 15.9577 4
created -0.1 39.8942 10
created 0.5 3.98942 1
created 1.1 15.9577 4
created 1.7 7.97885 2
created 2.3 35.9048 9
created 2.9 39.8942 10
created 3.5 27.926 7
created 4.1 19.9471 5
created 4.7 7.97885 2
created 5.3 15.9577 4
created 5.9 19.9471 5
created 6.5 15.9577 4
created 7.1 19.9471 5
created 7.7 23.9365 6
created 8.3 35.9048 9
created 8.9 23.9365 6
created 9.5 15.9577 4
the total number of created peaks = 33 with sigma = 0.1
the total number of found peaks = 33 with sigma = 0.100002 (+-3.20086e-05)
fit chi^2 = 2.82272e-06
found -8.5 (+-0.000232981) 39.894 (+-0.0916976) 10.0001 (+-0.000752515)
found -0.100001 (+-0.000231813) 39.8937 (+-0.091645) 10.0001 (+-0.000752083)
found 2.9 (+-0.000233588) 39.8943 (+-0.091727) 10.0002 (+-0.000752757)
found -4.9 (+-0.000246169) 35.9048 (+-0.0870175) 9.00018 (+-0.000714108)
found 2.3 (+-0.000245612) 35.9047 (+-0.0869954) 9.00015 (+-0.000713927)
found 8.3 (+-0.000245907) 35.9047 (+-0.0870059) 9.00015 (+-0.000714013)
found -9.7 (+-0.000260551) 31.915 (+-0.0820128) 8.00007 (+-0.000673037)
found -5.5 (+-0.000260597) 31.9153 (+-0.0820231) 8.00014 (+-0.000673122)
found -2.5 (+-0.000259228) 31.915 (+-0.0819713) 8.00005 (+-0.000672697)
found 3.5 (+-0.000279759) 27.9262 (+-0.0767646) 7.00019 (+-0.000629968)
found -7.3 (+-0.000277949) 27.9258 (+-0.0767047) 7.00009 (+-0.000629476)
found -7.9 (+-0.000302982) 23.937 (+-0.0710946) 6.00022 (+-0.000583437)
found -4.3 (+-0.000301877) 23.9367 (+-0.0710619) 6.00016 (+-0.000583169)
found 8.9 (+-0.000302168) 23.9368 (+-0.0710702) 6.00017 (+-0.000583237)
found 7.7 (+-0.000302416) 23.9368 (+-0.0710774) 6.00018 (+-0.000583296)
found -9.1 (+-0.000332683) 19.9477 (+-0.0649206) 5.00023 (+-0.000532771)
found 4.1 (+-0.000330361) 19.9472 (+-0.0648624) 5.00012 (+-0.000532293)
found 5.9 (+-0.000330356) 19.9471 (+-0.0648611) 5.0001 (+-0.000532282)
found 7.1 (+-0.000330896) 19.9473 (+-0.0648747) 5.00013 (+-0.000532393)
found 6.5 (+-0.000370693) 15.9579 (+-0.0580405) 4.00013 (+-0.000476309)
found 9.5 (+-0.000367016) 15.9579 (+-0.0579793) 4.00013 (+-0.000475807)
found -0.699995 (+-0.000369965) 15.958 (+-0.0580297) 4.00014 (+-0.00047622)
found 1.1 (+-0.000367452) 15.9575 (+-0.0579775) 4.00004 (+-0.000475792)
found 5.3 (+-0.000369418) 15.9577 (+-0.0580155) 4.00009 (+-0.000476103)
found -3.7 (+-0.000428595) 11.9685 (+-0.0502736) 3.00012 (+-0.00041257)
found -3.1 (+-0.000429263) 11.9686 (+-0.0502845) 3.00014 (+-0.000412659)
found 1.70001 (+-0.000529149) 7.97937 (+-0.041094) 2.00017 (+-0.000337238)
found -6.09999 (+-0.000525699) 7.97917 (+-0.0410591) 2.00012 (+-0.000336951)
found 4.7 (+-0.000527239) 7.97916 (+-0.0410725) 2.00012 (+-0.000337061)
found 0.499987 (+-0.000756005) 3.99008 (+-0.0291024) 1.00018 (+-0.000238828)
found -1.90002 (+-0.000749057) 3.98982 (+-0.0290646) 1.00012 (+-0.000238518)
found -6.70001 (+-0.000750717) 3.98982 (+-0.0290721) 1.00012 (+-0.00023858)
found -1.29999 (+-0.000745333) 3.98961 (+-0.0290422) 1.00007 (+-0.000238334)
#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;
}
d
#define d(i)
Definition: RSha256.hxx:102
f
#define f(i)
Definition: RSha256.hxx:104
h
#define h(i)
Definition: RSha256.hxx:106
x1
static const double x1[5]
Definition: RooGaussKronrodIntegrator1D.cxx:326
Int_t
int Int_t
Definition: RtypesCore.h:41
kFALSE
const Bool_t kFALSE
Definition: RtypesCore.h:88
Bool_t
bool Bool_t
Definition: RtypesCore.h:59
Double_t
double Double_t
Definition: RtypesCore.h:55
kRed
@ kRed
Definition: Rtypes.h:63
xmin
float xmin
Definition: THbookFile.cxx:93
xmax
float xmax
Definition: THbookFile.cxx:93
gROOT
#define gROOT
Definition: TROOT.h:410
gRandom
R__EXTERN TRandom * gRandom
Definition: TRandom.h:62
TAttMarker::SetMarkerColor
virtual void SetMarkerColor(Color_t mcolor=1)
Set the marker color.
Definition: TAttMarker.h:38
TAttMarker::SetMarkerStyle
virtual void SetMarkerStyle(Style_t mstyle=1)
Set the marker style.
Definition: TAttMarker.h:40
TAttMarker::SetMarkerSize
virtual void SetMarkerSize(Size_t msize=1)
Set the marker size.
Definition: TAttMarker.h:41
TCanvas
The Canvas class.
Definition: TCanvas.h:31
TCanvas::Clear
void Clear(Option_t *option="")
Remove all primitives from the canvas.
Definition: TCanvas.cxx:712
TF1
1-Dim function class
Definition: TF1.h:211
TH1F
1-D histogram with a float per channel (see TH1 documentation)}
Definition: TH1.h:571
TPolyMarker
A PolyMarker is defined by an array on N points in a 2-D space.
Definition: TPolyMarker.h:31
TRandom::SetSeed
virtual void SetSeed(ULong_t seed=0)
Set the random generator seed.
Definition: TRandom.cxx:589
TRandom::Uniform
virtual Double_t Uniform(Double_t x1=1)
Returns a uniform deviate on the interval (0, x1).
Definition: TRandom.cxx:627
TSpectrumFit
Advanced 1-dimensional spectra fitting functions.
Definition: TSpectrumFit.h:18
TSpectrumFit::GetChi
Double_t GetChi() const
Definition: TSpectrumFit.h:121
TSpectrumFit::SetPeakParameters
void SetPeakParameters(Double_t sigma, Bool_t fixSigma, const Double_t *positionInit, const Bool_t *fixPosition, const Double_t *ampInit, const Bool_t *fixAmp)
This function sets the following fitting parameters of peaks:
Definition: TSpectrumFit.cxx:2656
TSpectrumFit::GetAmplitudesErrors
Double_t * GetAmplitudesErrors() const
Definition: TSpectrumFit.h:117
TSpectrumFit::FitAwmi
void FitAwmi(Double_t *source)
This function fits the source spectrum.
Definition: TSpectrumFit.cxx:820
TSpectrumFit::GetAreasErrors
Double_t * GetAreasErrors() const
Definition: TSpectrumFit.h:119
TSpectrumFit::GetSigma
void GetSigma(Double_t &sigma, Double_t &sigmaErr)
This function gets the sigma parameter and its error.
Definition: TSpectrumFit.cxx:2725
TSpectrumFit::GetAreas
Double_t * GetAreas() const
Definition: TSpectrumFit.h:118
TSpectrumFit::GetAmplitudes
Double_t * GetAmplitudes() const
Definition: TSpectrumFit.h:116
TSpectrumFit::SetFitParameters
void SetFitParameters(Int_t xmin, Int_t xmax, Int_t numberIterations, Double_t alpha, Int_t statisticType, Int_t alphaOptim, Int_t power, Int_t fitTaylor)
This function sets the following fitting parameters:
Definition: TSpectrumFit.cxx:2608
TSpectrumFit::kFitTaylorOrderFirst
@ kFitTaylorOrderFirst
Definition: TSpectrumFit.h:82
TSpectrumFit::GetPositionsErrors
Double_t * GetPositionsErrors() const
Definition: TSpectrumFit.h:123
TSpectrumFit::GetPositions
Double_t * GetPositions() const
Definition: TSpectrumFit.h:122
TSpectrum
Advanced Spectra Processing.
Definition: TSpectrum.h:18
sigma
const Double_t sigma
Definition: h1analysisProxy.h:11
TGeoUnit::s
static constexpr double s
Definition: TGeoSystemOfUnits.h:162
TMath::Sqrt2
constexpr Double_t Sqrt2()
Definition: TMath.h:89
TMath::Sqrt
Double_t Sqrt(Double_t x)
Definition: TMath.h:679
TMath::TwoPi
constexpr Double_t TwoPi()
Definition: TMath.h:45
dest
#define dest(otri, vertexptr)
Definition: triangle.c:1040
Author

Definition in file FitAwmi.C.