void fit_waveform15(void)
{
//=========Macro generated from canvas: c1/c1
//=========  (Wed Dec 17 14:52:30 2014) by ROOT version5.34/19
   TCanvas *c1 = new TCanvas("c1", "c1",1535,353,775,652);

gROOT->Reset();
//TTree *Bfield = (TTree *) gROOT->FindObject("Bfield");
gStyle->SetPalette(1,0);
gStyle->SetOptStat(kTRUE);
gStyle->SetOptFit(kTRUE);
gStyle->SetOptFit(1111);
gStyle->SetPadRightMargin(0.15);
gStyle->SetPadLeftMargin(0.15);
gStyle->SetPadBottomMargin(0.15);
gStyle->SetFillColor(0);
//

   gStyle->SetOptStat(0);
   c1->Range(-21.79487,-16.8,106.4103,95.2);
   c1->SetFillColor(0);
   c1->SetBorderMode(0);
   c1->SetBorderSize(2);
   c1->SetLeftMargin(0.17);
   c1->SetRightMargin(0.05);
   c1->SetBottomMargin(0.15);
   c1->SetFrameBorderMode(0);
   c1->SetFrameBorderMode(0);
   
   TH1F *hist15 = new TH1F("hist15","Ch=40,06,06",100,0,100);
   hist15->SetBinContent(1,1);
   hist15->SetBinContent(2,2);
   hist15->SetBinContent(3,2);
   hist15->SetBinContent(4,1);
   hist15->SetBinContent(5,1);
   hist15->SetBinContent(6,1);
   hist15->SetBinContent(7,2);
   hist15->SetBinContent(9,2);
   hist15->SetBinContent(10,2);
   hist15->SetBinContent(11,1);
   hist15->SetBinContent(12,1);
   hist15->SetBinContent(13,2);
   hist15->SetBinContent(14,2);
   hist15->SetBinContent(15,3);
   hist15->SetBinContent(16,1);
   hist15->SetBinContent(17,3);
   hist15->SetBinContent(18,5);
   hist15->SetBinContent(19,3);
   hist15->SetBinContent(20,2);
   hist15->SetBinContent(21,3);
   hist15->SetBinContent(22,3);
   hist15->SetBinContent(23,2);
   hist15->SetBinContent(24,3);
   hist15->SetBinContent(25,1);
   hist15->SetBinContent(26,1);
   hist15->SetBinContent(27,2);
   hist15->SetBinContent(28,3);
   hist15->SetBinContent(29,3);
   hist15->SetBinContent(30,3);
   hist15->SetBinContent(32,2);
   hist15->SetBinContent(33,2);
   hist15->SetBinContent(34,3);
   hist15->SetBinContent(35,2);
   hist15->SetBinContent(36,3);
   hist15->SetBinContent(37,2);
   hist15->SetBinContent(38,5);
   hist15->SetBinContent(39,14);
   hist15->SetBinContent(40,26);
   hist15->SetBinContent(41,27);
   hist15->SetBinContent(42,27);
   hist15->SetBinContent(43,27);
   hist15->SetBinContent(44,28);
   hist15->SetBinContent(45,25);
   hist15->SetBinContent(46,23);
   hist15->SetBinContent(47,19);
   hist15->SetBinContent(48,18);
   hist15->SetBinContent(49,17);
   hist15->SetBinContent(50,14);
   hist15->SetBinContent(51,17);
   hist15->SetBinContent(52,12);
   hist15->SetBinContent(53,11);
   hist15->SetBinContent(54,11);
   hist15->SetBinContent(55,12);
   hist15->SetBinContent(56,9);
   hist15->SetBinContent(57,9);
   hist15->SetBinContent(58,9);
   hist15->SetBinContent(59,10);
   hist15->SetBinContent(60,9);
   hist15->SetBinContent(61,8);
   hist15->SetBinContent(62,8);
   hist15->SetBinContent(63,6);
   hist15->SetBinContent(64,5);
   hist15->SetBinContent(65,7);
   hist15->SetBinContent(66,8);
   hist15->SetBinContent(67,6);
   hist15->SetBinContent(68,5);
   hist15->SetBinContent(69,5);
   hist15->SetBinContent(70,8);
   hist15->SetBinContent(71,8);
   hist15->SetBinContent(72,8);
   hist15->SetBinContent(73,7);
   hist15->SetBinContent(74,4);
   hist15->SetBinContent(75,6);
   hist15->SetBinContent(76,4);
   hist15->SetBinContent(77,5);
   hist15->SetBinContent(78,3);
   hist15->SetBinContent(79,2);
   hist15->SetBinContent(80,2);
   hist15->SetBinContent(81,1);
   hist15->SetBinContent(82,4);
   hist15->SetBinContent(83,2);
   hist15->SetBinContent(84,3);
   hist15->SetBinContent(85,3);
   hist15->SetBinContent(86,1);
   hist15->SetBinContent(87,2);
   hist15->SetBinContent(88,1);
   hist15->SetBinContent(90,2);
   hist15->SetBinContent(92,2);
   hist15->SetBinContent(93,3);
   hist15->SetBinContent(94,3);
   hist15->SetBinContent(95,3);
   hist15->SetBinContent(96,2);
   hist15->SetBinContent(97,1);
   hist15->SetBinContent(98,3);
   hist15->SetBinContent(99,2);
   hist15->SetBinContent(100,2);
   hist15->SetMaximum(84);
   hist15->SetEntries(1100);
   // hist15->SetStats(0);
   hist15->SetLineColor(2);
   hist15->GetXaxis()->SetTitle("sample   (4 ns)");
   hist15->GetXaxis()->SetNdivisions(505);
   hist15->GetXaxis()->SetLabelFont(42);
   hist15->GetXaxis()->SetLabelSize(0.07);
   hist15->GetXaxis()->SetTitleSize(0.07);
   hist15->GetXaxis()->SetTitleFont(42);
   hist15->GetYaxis()->SetTitle("ADC value");
   hist15->GetYaxis()->SetNdivisions(505);
   hist15->GetYaxis()->SetLabelFont(42);
   hist15->GetYaxis()->SetLabelSize(0.07);
   hist15->GetYaxis()->SetTitleSize(0.07);
   hist15->GetYaxis()->SetTitleOffset(1.2);
   hist15->GetYaxis()->SetTitleFont(42);
   hist15->GetZaxis()->SetLabelFont(42);
   hist15->GetZaxis()->SetLabelSize(0.07);
   hist15->GetZaxis()->SetTitleSize(0.07);
   hist15->GetZaxis()->SetTitleFont(42);
   hist15->Draw("");
   
   TPaveText *pt = new TPaveText(0,0.9046154,0.40262,0.995,"blNDC");
   pt->SetName("title");
   pt->SetBorderSize(0);
   pt->SetFillColor(0);
   pt->SetFillStyle(0);
   pt->SetTextFont(42);
   TText *text = pt->AddText("Ch=40,06,06");
   pt->Draw();
   c1->Modified();
   c1->cd();
   c1->SetSelected(c1);


   // define pulse function

   Double_t xmin=0;
   Double_t xmax=100;

   TF1 *pulse = new TF1("pulse_func",pulse_func,xmin,xmax,5);
   Double_t mu=1/8.;    // unis of 1/x
   Double_t sigma=5;     // units of x 
   Double_t gain=500;   
   Double_t t0=40;
   Double_t pedestal=2;
   pulse->SetParameters(mu,sigma,gain,t0,pedestal);
   pulse->SetParNames("mu","sigma","gain","t0","pedestal");
  
   hist15->Fit(pulse);
   c1->SaveAs("fit_waveform15.pdf");

}
Double_t pulse_func (Double_t *x, Double_t *par) {

   Double_t mu=par[0];
   Double_t sigma=par[1];
   Double_t gain=par[2];
   Double_t t0=par[3];
   Double_t pedestal=par[4];
   Double_t x1=x[0]-t0;

   char string[256];

   Double_t func;
   Double_t amplitude;

   if (x1 < -20) {
           func = pedestal;
           }
   else if {

         Double_t arg = (mu*sigma*sigma-x1)/(sqrt(2)*sigma);
         Double_t arg2 = -mu*x1 +(mu*sigma)*(mu*sigma)/2;
         amplitude = (mu/2)* exp(arg2) *  TMath::Erfc(arg);
          func = gain * amplitude + pedestal;
  }
   
   /*sprintf (string,"x1=%f amplitude=%f mu=%f sigma=%f t0=%f pedestal=%f, func=%f\n",x1,amplitude,mu,sigma,pedestal,func);
   printf ("string=%s",string);*/

   return func;
}