TemplateFunction.C

#ifndef TEMPLATE_FUNCTION__C
#define TEMPLATE_FUNCTION__C
#include "FunctionObject.h"
#include "TMath.h"
#include "TH1.h"
#include "TRandom.h"
class TemplateFunction: public FunctionObject {
 public:
   TemplateFunction():baseTemplate(0),backupTemplate(0) {};
   TemplateFunction(TH1 *inh):baseTemplate(inh){};
   ~TemplateFunction(){ delete backupTemplate; };
   double operator() (double *x, double *p);
   double getError(double *x, double *p);
   Bool_t isValid() { return baseTemplate?kTRUE:kFALSE;};
   void SetBaseTemplate(TH1 *inh) {baseTemplate=inh;};
   void Randomize();
   void Restore();
 protected:
   TH1 *baseTemplate; //! Not stored by the function, do not delete
   TH1 *backupTemplate;
};
double TemplateFunction::operator()(double *x, double *p) {
  Double_t bc = baseTemplate->GetBinContent(baseTemplate->FindBin(x[0]));
  return p[0]*bc + p[1]*(1 + 2*p[2]*TMath::Cos(2*x[0]) + 2*p[3]*TMath::Cos(3*x[0]));
};
double TemplateFunction::getError(double *x, double *p) { //This is absolutely optional, implemented here b/c I used the same function for TMinuit & TFractionFitters
  return baseTemplate->GetBinError(baseTemplate->FindBin(x[0])) * p[0];
};
void TemplateFunction::Randomize() {
  if(!backupTemplate) backupTemplate = (TH1*)baseTemplate->Clone(Form("%s_backup",baseTemplate->GetName()));
  for(Int_t i=1;i<=baseTemplate->GetNbinsX();i++)
    baseTemplate->SetBinContent(i,gRandom->Gaus(backupTemplate->GetBinContent(i),backupTemplate->GetBinError(i)));
};
void TemplateFunction::Restore() {
  if(!backupTemplate) {printf("Nothing to restore\n"); return; };
  for(Int_t i=1;i<=baseTemplate->GetNbinsX();i++) {
    baseTemplate->SetBinContent(i,backupTemplate->GetBinContent(i));
    baseTemplate->SetBinError(i,backupTemplate->GetBinError(i));
  };
}
#endif