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FitAwmi.C File Reference
Tutorials » Legacy tutorials » Spectrum tutorials

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 -9.76 4.98678 1
created -9.28 19.9471 4
created -8.8 39.8942 8
created -8.32 9.97356 2
created -7.84 9.97356 2
created -7.36 19.9471 4
created -6.88 14.9603 3
created -6.4 19.9471 4
created -5.92 39.8942 8
created -5.44 29.9207 6
created -4.96 14.9603 3
created -4.48 4.98678 1
created -4 29.9207 6
created -3.52 19.9471 4
created -3.04 44.881 9
created -2.56 9.97356 2
created -2.08 39.8942 8
created -1.6 29.9207 6
created -1.12 24.9339 5
created -0.64 39.8942 8
created -0.16 4.98678 1
created 0.32 49.8678 10
created 0.8 29.9207 6
created 1.28 39.8942 8
created 1.76 39.8942 8
created 2.24 49.8678 10
created 2.72 49.8678 10
created 3.2 49.8678 10
created 3.68 19.9471 4
created 4.16 39.8942 8
created 4.64 34.9074 7
created 5.12 49.8678 10
created 5.6 34.9074 7
created 6.08 4.98678 1
created 6.56 29.9207 6
created 7.04 39.8942 8
created 7.52 29.9207 6
created 8 14.9603 3
created 8.48 49.8678 10
created 8.96 4.98678 1
created 9.44 49.8678 10
the total number of created peaks = 41 with sigma = 0.08
the total number of found peaks = 41 with sigma = 0.0800011 (+-3.07495e-05)
fit chi^2 = 5.64563e-06
found 0.320001 (+-0.00026034) 49.8675 (+-0.16064) 10.0001 (+-0.00106379)
found 2.24 (+-0.000262242) 49.868 (+-0.160778) 10.0002 (+-0.0010647)
found 2.72 (+-0.000262471) 49.8681 (+-0.160795) 10.0002 (+-0.00106482)
found 3.2 (+-0.00026164) 49.8678 (+-0.160733) 10.0001 (+-0.0010644)
found 5.12 (+-0.000261758) 49.8678 (+-0.16074) 10.0001 (+-0.00106445)
found 8.48 (+-0.00025981) 49.8673 (+-0.160601) 10 (+-0.00106353)
found 9.44 (+-0.000258312) 49.8677 (+-0.160511) 10.0001 (+-0.00106293)
found -3.04 (+-0.000274593) 44.8807 (+-0.152404) 9.00006 (+-0.00100925)
found -8.8 (+-0.000291435) 39.894 (+-0.143699) 8.00006 (+-0.0009516)
found -5.92 (+-0.000292397) 39.8942 (+-0.143755) 8.0001 (+-0.000951973)
found -2.08 (+-0.000291835) 39.8941 (+-0.143723) 8.00008 (+-0.000951761)
found -0.640001 (+-0.000291222) 39.894 (+-0.143689) 8.00006 (+-0.000951534)
found 1.28 (+-0.000293126) 39.8944 (+-0.1438) 8.00014 (+-0.000952267)
found 1.76 (+-0.000293729) 39.8946 (+-0.143837) 8.00018 (+-0.000952517)
found 4.16 (+-0.000292566) 39.8943 (+-0.143766) 8.00011 (+-0.000952042)
found 7.04 (+-0.0002928) 39.8943 (+-0.143779) 8.00012 (+-0.000952133)
found 4.64 (+-0.000314374) 34.9079 (+-0.134568) 7.00018 (+-0.000891133)
found 5.6 (+-0.000312427) 34.9075 (+-0.134469) 7.00011 (+-0.000890477)
found -5.44 (+-0.000338419) 29.9208 (+-0.124533) 6.00011 (+-0.00082468)
found -1.6 (+-0.000339022) 29.9209 (+-0.12456) 6.00013 (+-0.00082486)
found 0.8 (+-0.000340041) 29.9212 (+-0.124609) 6.00018 (+-0.000825183)
found 7.52 (+-0.000338419) 29.9208 (+-0.124533) 6.00011 (+-0.00082468)
found -4 (+-0.000336536) 29.9205 (+-0.124449) 6.00005 (+-0.000824124)
found 6.56 (+-0.000337459) 29.9207 (+-0.124493) 6.00009 (+-0.000824415)
found -1.12 (+-0.000372249) 24.9343 (+-0.113742) 5.00014 (+-0.000753219)
found -3.52 (+-0.000417332) 19.9476 (+-0.101771) 4.00015 (+-0.000673949)
found 3.68 (+-0.000418171) 19.9478 (+-0.101799) 4.00018 (+-0.000674133)
found -9.28 (+-0.000414481) 19.9473 (+-0.101685) 4.00009 (+-0.000673376)
found -7.36 (+-0.000413511) 19.9471 (+-0.10165) 4.00005 (+-0.000673146)
found -6.4 (+-0.000415863) 19.9474 (+-0.101725) 4.00011 (+-0.00067364)
found -6.88 (+-0.000480388) 14.9605 (+-0.0880995) 3.00008 (+-0.000583411)
found -4.96 (+-0.000478957) 14.9605 (+-0.0880691) 3.00007 (+-0.00058321)
found 8 (+-0.000483677) 14.961 (+-0.0881819) 3.00016 (+-0.000583957)
found -2.56 (+-0.000595956) 9.97429 (+-0.0720622) 2.00017 (+-0.000477209)
found -8.32 (+-0.000591149) 9.97394 (+-0.0719818) 2.0001 (+-0.000476676)
found -7.84 (+-0.000588778) 9.97373 (+-0.0719404) 2.00006 (+-0.000476402)
found -0.159997 (+-0.000852365) 4.98763 (+-0.0510437) 1.00018 (+-0.000338021)
found 8.96 (+-0.000853977) 4.98774 (+-0.051059) 1.00021 (+-0.000338122)
found 6.08 (+-0.000847942) 4.98738 (+-0.0510022) 1.00013 (+-0.000337746)
found -4.48 (+-0.000843005) 4.98717 (+-0.0509581) 1.00009 (+-0.000337454)
found -9.75999 (+-0.000833971) 4.98692 (+-0.0508794) 1.00004 (+-0.000336932)
#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
Bool_t
bool Bool_t
Boolean (0=false, 1=true) (bool)
Definition RtypesCore.h:77
Int_t
int Int_t
Signed integer 4 bytes (int)
Definition RtypesCore.h:59
kFALSE
constexpr Bool_t kFALSE
Definition RtypesCore.h:108
Double_t
double Double_t
Double 8 bytes.
Definition RtypesCore.h:73
kRed
@ kRed
Definition Rtypes.h:67
TRangeDynCast
ROOT::Detail::TRangeCast< T, true > TRangeDynCast
TRangeDynCast is an adapter class that allows the typed iteration through a TCollection.
Definition TCollection.h:360
dest
Option_t Option_t TPoint TPoint const char GetTextMagnitude GetFillStyle GetLineColor GetLineWidth GetMarkerStyle GetTextAlign GetTextColor GetTextSize void char Point_t Rectangle_t dest
Definition TGWin32VirtualXProxy.cxx:164
x1
Option_t Option_t TPoint TPoint const char x1
Definition TGWin32VirtualXProxy.cxx:70
xmin
float xmin
Definition THbookFile.cxx:95
xmax
float xmax
Definition THbookFile.cxx:95
gROOT
#define gROOT
Definition TROOT.h:426
gRandom
R__EXTERN TRandom * gRandom
Definition TRandom.h:62
TCanvas
The Canvas class.
Definition TCanvas.h:23
TF1
1-Dim function class
Definition TF1.h:182
TH1F
1-D histogram with a float per channel (see TH1 documentation)
Definition TH1.h:878
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:614
TRandom::Uniform
virtual Double_t Uniform(Double_t x1=1)
Returns a uniform deviate on the interval (0, x1).
Definition TRandom.cxx:681
TSpectrumFit
Advanced 1-dimensional spectra fitting functions.
Definition TSpectrumFit.h:18
TSpectrum
Advanced Spectra Processing.
Definition TSpectrum.h:18
TSpectrum::SearchHighRes
Int_t SearchHighRes(Double_t *source, Double_t *destVector, Int_t ssize, Double_t sigma, Double_t threshold, bool backgroundRemove, Int_t deconIterations, bool markov, Int_t averWindow)
One-dimensional high-resolution peak search function.
Definition TSpectrum.cxx:2118
TSpectrum::GetPositionX
Double_t * GetPositionX() const
Definition TSpectrum.h:58
sigma
const Double_t sigma
Definition h1analysisProxy.h:11
TMath::Sqrt2
constexpr Double_t Sqrt2()
Definition TMath.h:89
TMath::Sqrt
Double_t Sqrt(Double_t x)
Returns the square root of x.
Definition TMath.h:673
TMath::TwoPi
constexpr Double_t TwoPi()
Definition TMath.h:47
Author

Definition in file FitAwmi.C.