# NueFit2D.h File Reference

`#include "TROOT.h"`
`#include "NueAna/MultiBinAna/Extrapolate2D.h"`
`#include "NueAna/MultiBinAna/ErrorCalc.h"`
`#include "TH2D.h"`
`#include "TH1D.h"`
`#include "TMath.h"`
`#include "TCanvas.h"`
`#include <vector>`
`#include "TMatrixD.h"`
`#include <string>`
`#include "TMinuit.h"`
`#include "TObject.h"`
`#include "TGraph.h"`
`#include "TGraph2D.h"`
`#include <iostream>`
`#include "TSystem.h"`
`#include "TRandom.h"`
`#include "TF1.h"`
`#include "TMatrixDEigen.h"`

Go to the source code of this file.

class  NueFit2D

## Functions

double Poisson (double mean, int n, bool numOnly=false)
double Gaussian (double x, double mean, double sig)

## Function Documentation

 double Gaussian ( double x, double mean, double sig )

Definition at line 50 of file NueFit2D.cxx.

```00051 {
00052   double front = 1/TMath::Sqrt(2*3.1415926*sig);
00053   double exp = (x-mean)*(x-mean)/(2*sig);
00054   return front*TMath::Exp(-exp);
00055 }
```

 double Poisson ( double mean, int n, bool numOnly = `false` )

Definition at line 31 of file NueFit2D.cxx.

```00032 {
00033   double numerator = 1;
00034   if(mean > 100 || n > 100){
00035       // use roots protected function -
00036     if(!numOnly) return TMath::Poisson(n, mean);
00037
00038       // else     pull a trick to prevent explosions
00039     double logN = n*TMath::Log(mean) - mean;
00040     numerator = TMath::Exp(logN);
00041   }
00042   else{
00043     numerator = TMath::Power(mean,n)*TMath::Exp(-mean);
00044   }
00045   double denom = 1.0;
00046   if(!numOnly) denom = TMath::Factorial(n);
00047   return numerator/denom;
00048 }
```

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