//---------this program is to draw  the 2D graph of en ,angle,cs ,cserror
//-------and fit them with legendre 

#include <TMath.h>
#include <TGraph2DErrors.h>
#include <TRandom.h>
#include <TStyle.h>
#include <TCanvas.h>
#include <TF2.h>
#include "TMultiGraph.h"
#include <iostream>
#include <TF1.h>


//----------first ,construct the function using to fit



//=====================================================================
Double_t fit_0(  Double_t *x,Double_t *y ,Double_t *par)
{
      Double_t fitval=par[0]*TMath::Exp(par[1]*x[0])+par[2]*TMath::Exp(par[3]*x[0])+(par[4]+par[5]*x[0])/(1+par[6]*(x[0]-par[7])*(x[0]-par[7]));
      return fitval;
 }


//====================================================================== 
//建立A1P1函数
Double_t  fit_1(  Double_t *x,Double_t *y ,Double_t *par) 
{
      Double_t fitval=(par[0]*TMath::Exp(par[1]*x[0])+par[2]*TMath::Exp(par[3]*x[0]))*ROOT::Math::assoc_legendre(1,0,cos(y[0]*TMath::Pi()/180));  
      return fitval;
}

//======================================================================
//建立 2 函数
Double_t  fit_2(  Double_t *x,Double_t *y ,Double_t *par) 
{
      Double_t fitval=(par[0]*TMath::Exp(par[1]*x[0])+par[2]*TMath::Exp(par[3]*x[0]))*ROOT::Math::assoc_legendre(2,0,cos(y[0]*TMath::Pi()/180));  
      return fitval;
}

//======================================================================
//建立 3 函数
Double_t  fit_3(  Double_t *x,Double_t *y ,Double_t *par) 
{
      Double_t fitval=(par[0]*TMath::Exp(par[1]*x[0])+par[2]*TMath::Exp(par[3]*x[0]))*ROOT::Math::assoc_legendre(3,0,cos(y[0]*TMath::Pi()/180));  
      return fitval;
}

//======================================================================
//建立 4 函数
Double_t  fit_4(  Double_t *x,Double_t *y ,Double_t *par) 
{
      Double_t fitval=(par[0]*TMath::Exp(par[1]*x[0])+par[2]*TMath::Exp(par[3]*x[0]))*ROOT::Math::assoc_legendre(4,0,cos(y[0]*TMath::Pi()/180));  
                    
      return fitval;
}

//======================================================================
//建立 5 函数
Double_t  fit_5(  Double_t *x,Double_t *y ,Double_t *par) 
{
      Double_t fitval=(par[0]*TMath::Exp(par[1]*x[0])+par[2]*TMath::Exp(par[3]*x[0]))*ROOT::Math::assoc_legendre(5,0,cos(y[0]*TMath::Pi()/180));  
      return fitval;
}


//sum of the fit function

Double_t fit_f( Double_t *x,Double_t *y, Double_t *par)
{
    Double_t fitval=fit_5(x,y,&par[24])+fit_4(x,y,&par[20])+fit_3(x,y,&par[16])+fit_2(x,y,&par[12])+ fit_1(x,y,&par[8])+fit_0(x,y,par);
                  ;
               
    return fitval;
}







//==============================================================
//--------------------------------------------------------------

//            construct the main function 


//--------------------------------------------------------------
//==============================================================


void fit2Dg_of_diff()

{
   int counter=71;     // number of data point
	 Double_t en[71],angle[71],cs[71],cserror[71];
	 Double_t ex[71]=0;
	 Double_t ey[71]=0;
	 double zero;
	 int i;
	 
	 
	
	 gSystem->Load("libMathMore.dll");  
	 
	  TCanvas *myc = new TCanvas("myc", "Fitting a MultiGraph of  TGraphErrors");
	 
	 
	 // open the data file
	 ifstream alldata("c:\\root\\3he\\all_normalize_data\\all_diff_data.txt");
	 if(!alldata)
	 	  cout<<"No file"<<endl;
	 
	 for(i=0;i<counter;i++)
	 
	    alldata>>en[i]>>angle[i]>>cs[i]>>zero>>cserror[i];
	    
	  
	  
	  
	  TGraph2DErrors *f=new TGraph2DErrors(counter,en,angle,cs,ex,ey,cserror);
	    
	  f->Draw("surf1");
	  
	  
	  
	  
	  
	  //fit
	  
	  TF2 *f2=new TF2("fit",fit_f,4,150,0,180,8);
	  
	  f->Fit("fit4");
	  
	  
	}