#include "Riostream.h";
gRoot->Reset();

Double32_t p0,p1,p1err, p0err,p2,p2err,p[200],perr[200];
Double32_t x[9]={1,2,3,4,5,6,7,8,9};
Double32_t y[200],z[9][200],error[9][200];
Int_t i,j;

void fcn(Int_t &npar, Double_t *gin, Double_t &f, Double_t *par, Int_t iflag)
{
   const Int_t nbins = 9,max=34;
   Double_t chisq = 0;
   Double_t delta;
for (j=0;j<max;j ++)
{   
for (i=0;i<nbins; i++) 
   {
     delta  = (z[i][j]-func(x[i],y[j],par))/error[i][j];
     chisq += delta*delta;
} 
  }
   f = chisq;
}

Double_t func(Double32_t x, Double32_t y, Double32_t *par)
{ 
   Double_t arg = 0;
   arg = (-x*(par[0]-par[1]/y+par[2]*y)));
   Double_t value = par[j]*TMath::Exp(arg);
 return value;
}


void myfit()

{

ifstream in;
Double32_t b;	

TMinuit *gMinuit = new TMinuit(38);
gMinuit->SetFCN(fcn);
Double_t arglist[10];
   Int_t ierflg = 0;
   arglist[0] = 1;

//this file contains the values for p[j] from a previous fit only in t  
in.open("fit300.txt");

for (j=0; j<34;j++)
{
in>>b>>b>>b>>p[j]>>b; // ignore the other columns
}

in.close();

gMinuit->mnparm(0, "p0", 0.95, 0.01, 0,0,ierflg);
gMinuit->mnparm(1, "p1", 0.5, 0.01, 0,0,ierflg);
gMinuit->mnparm(2, "p2", 0.16, 0.01, 0,0,ierflg);
for (j=0;j<34;j++)
{
stringstream out;
out<<j+3;
string nume="p"+out.str();
gMinuit->mnparm(j+3,nume.c_str(), p[j], 0.01, 0,0,ierflg);
}


in.open("out300.txt");
for (j=0; j<114;j++)
{
y[j]=0;
in>>y[j]>>b; //ignore the second column
for (i=0; i<9; i++) 
{
in>>z[i][j]>>error[i][j];
}
}

arglist[0]=500;
arglist[1]=1.;
gMinuit->Migrad();
Double_t amin,edm,errdef;
Int_t nvpar,nparx,icstat;
gMinuit->mnstat(amin,edm,errdef,nvpar,nparx,icstat);
gMinuit->mnprin(3,amin);
gMinuit->GetParameter(1,p1,p1err);
gMinuit->GetParameter(0,p0,p0err);
gMinuit->GetParameter(0,p2,p2err);
for (j=0;j<34;j++)
{
stringstream out;
out<<j+3;
string nume="p"+out.str();
gMinuit->GetParameter(j+3,p[j],perr[j]);
}

}