minuit2GausFit.C File Reference

Detailed Description

Perform fits with different configurations using Minuit2

 
 
Do Fit 1
 
Do Fit 2
****************************************
Minimizer is Minuit2 / Migrad
Chi2                      =      65.1586
NDf                       =           56
Edm                       =  1.93774e-09
NCalls                    =           69
Constant                  =      36.3132   +/-   1.52625       -1.51651     +1.53547      (Minos) 
Mean                      =     0.013082   +/-   0.0347499     -0.0347674   +0.0347613    (Minos) 
Sigma                     =      1.03413   +/-   0.0288039     -0.0286274   +0.0290102    (Minos)      (limited)
 
Do Fit 3
****************************************
Minimizer is Minuit2 / Migrad
Chi2                      =      65.1586
NDf                       =           56
Edm                       =  6.86315e-08
NCalls                    =           57
Constant                  =       36.327   +/-   2             -1.51685     +1.53726      (Minos) 
Mean                      =    0.0130817   +/-   2           
Sigma                     =      1.03373   +/-   6.72116        (limited)
 
Do Fit 4
****************************************
Minimizer is Minuit2 / Migrad
MinFCN                    =      43.3935
Chi2                      =      86.7869
NDf                       =           97
Edm                       =  9.97216e-08
NCalls                    =           62
Constant                  =       38.427   +/-   1.48837       -1.46667     +1.51031      (Minos) 
Mean                      =     0.027601   +/-   0.032831      -0.0328395   +0.0328395    (Minos) 
Sigma                     =      1.03819   +/-   0.0232194     -0.0227841   +0.0236699    (Minos)      (limited)
 
Do Fit 1
 
Do Fit 2
****************************************
Minimizer is Minuit2 / Fumili
Chi2                      =      65.1586
NDf                       =           56
Edm                       =  8.05693e-09
NCalls                    =           45
Constant                  =      36.3131   +/-   1.52625       -1.51642     +1.53556      (Minos) 
Mean                      =    0.0130818   +/-   0.0347499     -0.0347671   +0.0347615    (Minos) 
Sigma                     =      1.03413   +/-   0.0288039     -0.0286291   +0.0290085    (Minos)      (limited)
 
Do Fit 3
****************************************
Minimizer is Minuit2 / Fumili
Chi2                      =      65.1586
NDf                       =           56
Edm                       =  1.52369e-08
NCalls                    =           45
Constant                  =      36.3272   +/-   1.52734       -1.51745     +1.53671      (Minos) 
Mean                      =    0.0130818   +/-   0.0347499     -0.0347671   +0.0347615    (Minos) 
Sigma                     =      1.03373   +/-   0.0288151     -0.0286415   +0.0290186    (Minos)      (limited)
 
Do Fit 4
****************************************
Minimizer is Minuit2 / Fumili
MinFCN                    =      43.3935
Chi2                      =      86.7869
NDf                       =           97
Edm                       =  3.18744e-08
NCalls                    =           45
Constant                  =      38.4264   +/-   1.48835       -1.46601     +1.51097      (Minos) 
Mean                      =    0.0275931   +/-   0.0328313     -0.0328316   +0.0328474    (Minos) 
Sigma                     =       1.0382   +/-   0.0232197     -0.0227928   +0.0236612    (Minos)      (limited)

 
#include "TH1.h"
#include "TF1.h"
#include "TCanvas.h"
#include "TRandom3.h"
#include "TVirtualFitter.h"
#include "TPaveLabel.h"
#include "TStyle.h"
 
#include <iostream>
#include <string>
 
 
void testGausFit( std::string type = "Minuit2", int n = 1000) {
 
   gRandom = new TRandom3();
 
   TVirtualFitter::SetDefaultFitter(type.c_str() );
 
   std::string name;
   name = "h1_" + type;
   TH1D * h1 = new TH1D(name.c_str(),"Chi2 Fit",100, -5, 5. );
   name = "h2_" + type;
   TH1D * h2 = new TH1D(name.c_str(),"Chi2 Fit with Minos Error",100, -5, 5. );
   name = "h3_" + type;
   TH1D * h3 = new TH1D(name.c_str(),"Chi2 Fit with Integral and Minos",100, -5, 5. );
   name = "h4_" + type;
   TH1D * h4 = new TH1D(name.c_str(),"Likelihood Fit with Minos Error",100, -5, 5. );
 
   gStyle->SetOptStat(1111111);
   gStyle->SetOptFit(1111111);
 
   for (int i = 0; i < n; ++i) {
      double x = gRandom->Gaus(0,1);
      h1->Fill( x );
      h2->Fill( x );
      h3->Fill( x );
      h4->Fill( x );
   }
 
   std::string cname = type + "Canvas" ;
   std::string ctitle = type + " Gaussian Fit" ;
   TCanvas *c1 = new TCanvas(cname.c_str(),cname.c_str(),10,10,900,900);
   c1->Divide(2,2);
 
   c1->cd(1);
   std::cout << "\nDo Fit 1\n";
   h1->Fit("gaus","Q");
   h1->Draw();
   c1->cd(2);
   std::cout << "\nDo Fit 2\n";
   h2->Fit("gaus","E");
   h2->Draw();
   c1->cd(3);
   std::cout << "\nDo Fit 3\n";
   h3->Fit("gaus","IGE");
   h3->Draw();
   c1->cd(4);
   std::cout << "\nDo Fit 4\n";
   h4->Fit("gaus","LE");
   h4->Draw();
 
}
 
void minuit2GausFit() {
 
   int n = 1000;
   testGausFit("Minuit2",n);
   testGausFit("Fumili2",n);
 
}

Author

Lorenzo Moneta

Definition in file minuit2GausFit.C.