#include <fstream>
#include <iostream>
#include <cmath>

#include "TROOT.h"
#include "TChain.h"
#include "TString.h"
#include "THStack.h"
#include "TF1.h"
#include "TCanvas.h"
#include "TPad.h"
#include "TH1.h"
#include "TH2.h"
#include "TLegend.h"
#include "TPaveText.h"
#include "TVirtualFitter.h"
#include "TMath.h"
#include "TClonesArray.h"
#include "TLatex.h"
#include "TStyle.h"
#include "TNamed.h"

using namespace std;

void myPadeRoot() 
{

   gROOT->Reset();

//Variables to use
   Double_t chi2 = 100;
   Double_t p0 = 0;
   Double_t p1 = 0;
   Double_t p2 = 0;
   Double_t p3 = 0;
   Double_t p4 = 0;
   Double_t p5 = 0;

//Take data form ascii file and plot it
   TGraph *mygraph = new TGraph("logdata.dat");
   mygraph->Draw("ALP"); 

//Set some Minimizer options
   ROOT::Math::MinimizerOptions::SetDefaultMinimizer("Minuit","Migrad"); // EL que viene por defecto
   ROOT::Math::MinimizerOptions::SetDefaultStrategy(2); // Para quee busque mejor el minimo y s eolvide de la rapidez
   ROOT::Math::MinimizerOptions::SetDefaultErrorDef(1); // 1 para chi^2 (default), 0.5 para log-likelihood

//Start the fit to the Padé aproximants, order by order

//Zeroth order [1,0]
   TF1 *P10 = new TF1("P10","[0]/(1-(([1]/[0])*x) )"); // Define the fit function
   P10->SetParameters(0,0); // Set initial parameters value
   mygraph->Fit("P10","EM+");
   p0 = P10->GetParameter(0); p1 = P10->GetParameter(1); chi2 = P10->GetChisquare();

//First order [1,1]
   TF1 *P11 = new TF1("P11","[0] + ([1]*x)/(1-(([2]/[1])*x) )"); 
   P11->SetParameters(p0,p1,0);
   mygraph->Fit("P11","EM+");
   p0 = P11->GetParameter(0); p1 = P11->GetParameter(1); p2 = P11->GetParameter(2); chi2 = P11->GetChisquare();

//Second order [1,2]
   TF1 *P12 = new TF1("P12","[0] + [1]*x + ([2]*x*x)/(1-(([3]/[2])*x) )"); 
   P12->SetParameters(p0,p1,p2,0);
   mygraph->Fit("P12","EM+");
   p0 = P12->GetParameter(0); p1 = P12->GetParameter(1); p2 = P12->GetParameter(2); p3 = P12->GetParameter(3); chi2 = P12->GetChisquare();

//Third order [1,3]
   TF1 *P13 = new TF1("P13","[0] + [1]*x + [2]*x*x + ([3]*x*x*x)/(1-(([4]/[3])*x) )"); 
   P13->SetParameters(p0,p1,p2,p3,0);
   mygraph->Fit("P13","EM+");
   chi2 = P13->GetChisquare();

//Fourth order [1,4]
   TF1 *P14 = new TF1("P14","[0] + [1]*x + [2]*x*x + [3]*x*x*x + ([4]*x*x*x*x)/(1-(([5]/[4])*x) )"); 
   P14->SetParameters(p0,p1,p2,p3,0,0);
   mygraph->Fit("P14","M+");
   TF1 *pade14 = mygraph->GetFunction("P14");


//Graph options
   gStyle->SetOptFit(1111); // gStyle->SetOptFit(pcev); p=probability, c=chi2/dof, e=print errors (if v=1), v=print name/values of parameters 


}