int DD3()
{
  //necessary declarations
 
  char datafile[100]="DDc1c2c3.txt";//This is where you specify which text file to read in
  ifstream data_input; //Creating a location in memory which will point to the data file

 
  /*
    The following variables are used to read in the data from a text file

    The format of the text file is as follows
  */
  float HV[100]; //An array of 100 elements which will contain the high voltages

  float Discr_L[5][100]={0};
  float Discr_H[5][100]={0}; 
  //A 2D array which will contain the raw count from the two discriminator settings, for each five counters
  
  int time[100]={0}; //Contains the run time for each measurement set
  
  

  float log_counts[5][100]={0}; //2D array which contains the log of the low discriminator counts
  float DD_Ratio[5][100]={0}; //2D array which contains the ratio of the two discriminator counts

  float x_errors[100]={0.0}; //Need to declare this as ROOT doesn't allow me to only give one set of errors
  float y_errors1[5][100]={0}; //2D array which contains the errors for the DD_Ratio
  float y_errors2[5][100]; //2D array which contains the error for the log of the counts

  int i=0, j=0, pts=0, time[100];
  float y_max1[5]=0, y_min1[5]=0, y_min2[5]=0, y_max2[5]=0, HV_min=0, HV_max=0;
  char xtitle[100], ytitle1[100], ytitle2[100], main_title[5][100];
 
  gStyle->SetOptStat(0);
  gStyle->SetErrorX(0);

  sprintf(xtitle, "High Voltage, [-kV]");
  sprintf(ytitle1, "Threshold 50/100");
  sprintf(ytitle2, "Log(Counts/s)");


  //read in data from file
  data_input.open(datafile);
  while(data_input >> HV[pts] >> Discr_L[0][pts] >> Discr_H[0][pts] >> Discr_L[1][pts] >> Discr_H[1][pts] >> Discr_L[2][pts] >> Discr_H[2][pts] >> time[pts])
    {
      pts++;
    }
  data_input.close();  

  for (j=0; j<3; j++)
    {

      sprintf(main_title[j], "c%d", j+1);

      for(i=0;i<(pts+1);i++)
	{
	  DD_Ratio[j][i]=Discr_L[j][i]/Discr_H[j][i];
	  log_counts[j][i]=log10(Discr_L[j][i]/time[i]);

	  y_errors1[j][i]=DD_Ratio[j][i]*sqrt(1/Discr_L[j][i]+1/Discr_H[j][i]);
	  y_errors2[j][i]=1/sqrt(Discr_L[j][i]/time[i]);
	  
	  if(j==0)
	    {
	      HV[i] /= 1000;
	      cout << HV[i] << endl;
	    }
	}
    }
  for (j=0; j<3; j++)
    {
      y_max1[j] = find_max(DD_Ratio[j], pts+1);
      y_min1[j] = find_min(DD_Ratio[j], pts+1);

      y_max2[j] = find_max(log_counts[j], pts+1);
      y_min2[j] = find_min(log_counts[j], pts+1);

    }

  HV_max = find_max(HV,pts+1);
  HV_min = find_min(HV,pts+1);




  TGraphErrors *graph[5];
  TGraphErrors *log_graph[5];
  TH2F *h2, *h2_dum;
  TCanvas *c, *canvas1, *canvas2; 
  g = (TGraphErrors*)gROOT->FindObject("graph"); if (g) g->Delete(); g=0;
  
  //initialize the graphs and set some characteristics
  for (j=0; j<3; j++)
    {
      graph[j] = new TGraphErrors(pts+1, HV, DD_Ratio[j], x_errors, y_errors1[j]);
      log_graph[j] = new TGraphErrors(pts+1, HV, log_counts[j], x_errors, y_errors2[j]);
    }


  c = (TCanvas*) gROOT->FindObject("DD"); if (c) delete c; c=0;
  c = (TCanvas*) gROOT->FindObject("Log"); if (c) delete c; c=0;

  canvas1 = new TCanvas("DD"," ",50,50,550,700);
  canvas1->Divide(2,3);

  canvas2 = new TCanvas("Log"," ",500,50,600,700);
  canvas2->Divide(2,3);

  for(j=0; j<3; j++)
    {
      canvas1->cd(j+1);
      h2 = (TH2F*)gROOT->FindObject("h2_dum"); if (h2) h2->Delete(); h2=0;
      h2_dum = new TH2F("h2_dum","", 0, 0.9*HV_min, 1.1*HV_max, 0, 0.9*y_min1[j], 1.2*y_max1[j]);
      h2_dum->SetXTitle(xtitle);
      h2_dum->SetTitleSize(0.037,"X");
      h2_dum->SetTitleSize(0.035, "Y");
      h2_dum->SetTitleOffset(1.5, "Y");

      h2_dum->SetTitle(main_title[j]);
      h2_dum->SetYTitle(ytitle1);	  

      h2_dum->DrawCopy();

      graph[j]->Draw("p");
      graph[j]->SetMarkerColor(2);
      graph[j]->SetMarkerStyle(20);
      graph[j]->SetMarkerSize(0.4);
      
      canvas2->cd(j+1);
      h2 = (TH2F*)gROOT->FindObject("h2_dum"); if (h2) h2->Delete(); h2=0;

      cout << y_min2[j] << endl;

      if(y_min2[j] < 1)
	{
	  y_min2[j] = 0.1*y_min2[j];
	}
      else
	{
	  y_min2[j] = 0.8*y_min2[j];
	}


      h2_dum = new TH2F("h2_dum","", 0, 0.9*HV_min, 1.1*HV_max, 0, y_min2[j], 1.2*y_max2[j]);
      h2_dum->SetXTitle(xtitle);
      h2_dum->SetTitleSize(0.037,"X");
      h2_dum->SetTitleSize(0.037, "Y");
      h2_dum->SetTitleOffset(1, "Y");
      
      h2_dum->SetTitle(main_title[j]);
      h2_dum->SetYTitle(ytitle2);	  
      
      h2_dum->DrawCopy();
      
      log_graph[j]->Draw("p");
      log_graph[j]->SetMarkerColor(2);
      log_graph[j]->SetMarkerStyle(20);
      log_graph[j]->SetMarkerSize(0.4);
      
    }



}


float find_max(const float *array, const int size)
{

  float max=array[0];
  
  for(int i=0;i<size;i++)
    if(max < array[i])
      max = array[i];
  
  return max;  
  
}

float find_min(const float *array, const int size)
{
 
  double min = array[0];
  
  for(int i = 0; i < size; i++)
    if( min > array[i] )
      min = array[i];
  
  return min;
}