//////////////////////////////////////////////////////////////////////////
//                                                                      //
// GFFuncs                                                              //
//                                                                      //
// Creator of TF1                                                       //
//                                                                      //
//////////////////////////////////////////////////////////////////////////

#include <iostream>

#include "TF1.h"

#include "GFFuncs.h"


ClassImp(GFFuncs)

 TF1* GFFuncs::CreateGaus(const char* name, Double_t xmin, Double_t xmax)
{
  // normalised (!!!) gaus function

  // sqrt(2pi) = 2.50662827463100024
  TF1* f = new TF1(name, "[0]/(2.50662827463100024*[2]) * exp(-(x-[1])*(x-[1])/(2*[2]*[2]))",
		   xmin, xmax);
  f->SetParameters(1., 0., 1.); // set 'normalised' start values...
  f->SetParNames("N*binwidth", "#mu", "#sigma");
  return f;
}

 TF1* GFFuncs::CreateDiGaus(const char* name, Double_t xmin, Double_t xmax)
{
  // overlay of two normalised gaus functions (6 params)

  // sqrt(2pi) = 2.50662827463100024
  TF1* f = new TF1(name, "[0]*[3]/(2.50662827463100024*[2])* exp(-(x-[1])*(x-[1])/(2*[2]*[2]))"
		   "+[0]*(1-[3])/(2.50662827463100024*[5]) * exp(-(x-[4])*(x-[4])/(2*[5]*[5]))",
		   xmin, xmax);
  f->SetParameters(1., 0., 1., 1., 0., 0.3); // set some start values...
  f->SetParNames("N*binwidth", "#mu_{1}", "#sigma_{1}",
		 "frac_{1}", "#mu_{2}", "#sigma_{2}");
  return f;
}

 TF1* GFFuncs::CreateDiGaus1Mean(const char* name, Double_t xmin, Double_t xmax)
{
  // overlay of two normalised gaus functions with same mean, i.e. 5 params

  // sqrt(2pi) = 2.50662827463100024
  TF1* f = new TF1(name, "[0]*[3]/(2.50662827463100024*[2])* exp(-(x-[1])*(x-[1])/(2*[2]*[2]))"
		   "+[0]*(1-[3])/(2.50662827463100024*[4]) * exp(-(x-[1])*(x-[1])/(2*[4]*[4]))",
		   xmin, xmax);
  f->SetParameters(1., 0., 1., 1., 0.3); // set some start values...
  f->SetParNames("N*binwidth", "#mu", "#sigma_{1}", "frac_{1}", "#sigma_{2}");
  return f;
}