void fit_waveform01(void)
{
//=========Macro generated from canvas: c1/c1
//=========  (Wed Dec 17 14:47:53 2014) by ROOT version5.34/19
   TCanvas *c1 = new TCanvas("c1", "c1",1505,246,779,672);

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);
//

   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 *hist01 = new TH1F("hist01","Ch=38,10,07",100,0,100);
   hist01->SetBinContent(1,3);
   hist01->SetBinContent(2,3);
   hist01->SetBinContent(3,2);
   hist01->SetBinContent(4,3);
   hist01->SetBinContent(5,1);
   hist01->SetBinContent(6,3);
   hist01->SetBinContent(8,3);
   hist01->SetBinContent(9,4);
   hist01->SetBinContent(10,3);
   hist01->SetBinContent(11,5);
   hist01->SetBinContent(12,2);
   hist01->SetBinContent(13,1);
   hist01->SetBinContent(14,1);
   hist01->SetBinContent(15,1);
   hist01->SetBinContent(16,1);
   hist01->SetBinContent(17,4);
   hist01->SetBinContent(18,2);
   hist01->SetBinContent(20,2);
   hist01->SetBinContent(22,1);
   hist01->SetBinContent(23,1);
   hist01->SetBinContent(24,1);
   hist01->SetBinContent(25,2);
   hist01->SetBinContent(26,3);
   hist01->SetBinContent(27,1);
   hist01->SetBinContent(28,1);
   hist01->SetBinContent(30,3);
   hist01->SetBinContent(31,1);
   hist01->SetBinContent(32,3);
   hist01->SetBinContent(33,1);
   hist01->SetBinContent(34,3);
   hist01->SetBinContent(35,5);
   hist01->SetBinContent(36,1);
   hist01->SetBinContent(37,2);
   hist01->SetBinContent(38,1);
   hist01->SetBinContent(39,9);
   hist01->SetBinContent(40,19);
   hist01->SetBinContent(41,28);
   hist01->SetBinContent(42,30);
   hist01->SetBinContent(43,29);
   hist01->SetBinContent(44,26);
   hist01->SetBinContent(45,28);
   hist01->SetBinContent(46,25);
   hist01->SetBinContent(47,22);
   hist01->SetBinContent(48,20);
   hist01->SetBinContent(49,20);
   hist01->SetBinContent(50,17);
   hist01->SetBinContent(51,15);
   hist01->SetBinContent(52,16);
   hist01->SetBinContent(53,12);
   hist01->SetBinContent(54,12);
   hist01->SetBinContent(55,10);
   hist01->SetBinContent(56,9);
   hist01->SetBinContent(57,9);
   hist01->SetBinContent(58,9);
   hist01->SetBinContent(59,9);
   hist01->SetBinContent(60,9);
   hist01->SetBinContent(61,6);
   hist01->SetBinContent(62,7);
   hist01->SetBinContent(63,7);
   hist01->SetBinContent(64,6);
   hist01->SetBinContent(65,5);
   hist01->SetBinContent(66,4);
   hist01->SetBinContent(67,4);
   hist01->SetBinContent(68,5);
   hist01->SetBinContent(69,5);
   hist01->SetBinContent(70,4);
   hist01->SetBinContent(71,4);
   hist01->SetBinContent(72,5);
   hist01->SetBinContent(73,4);
   hist01->SetBinContent(74,4);
   hist01->SetBinContent(75,5);
   hist01->SetBinContent(76,5);
   hist01->SetBinContent(77,5);
   hist01->SetBinContent(78,6);
   hist01->SetBinContent(79,4);
   hist01->SetBinContent(80,2);
   hist01->SetBinContent(81,7);
   hist01->SetBinContent(82,2);
   hist01->SetBinContent(83,3);
   hist01->SetBinContent(84,2);
   hist01->SetBinContent(85,3);
   hist01->SetBinContent(86,5);
   hist01->SetBinContent(87,3);
   hist01->SetBinContent(88,4);
   hist01->SetBinContent(89,4);
   hist01->SetBinContent(90,4);
   hist01->SetBinContent(92,5);
   hist01->SetBinContent(93,4);
   hist01->SetBinContent(94,1);
   hist01->SetBinContent(95,1);
   hist01->SetBinContent(96,4);
   hist01->SetBinContent(97,3);
   hist01->SetBinContent(98,2);
   hist01->SetBinContent(99,1);
   hist01->SetBinContent(100,4);
   hist01->SetMaximum(84);
   hist01->SetEntries(1100);
   // hist01->SetStats(0);
   hist01->SetLineColor(2);
   hist01->GetXaxis()->SetTitle("sample   (4 ns)");
   hist01->GetXaxis()->SetNdivisions(505);
   hist01->GetXaxis()->SetLabelFont(42);
   hist01->GetXaxis()->SetLabelSize(0.07);
   hist01->GetXaxis()->SetTitleSize(0.07);
   hist01->GetXaxis()->SetTitleFont(42);
   hist01->GetYaxis()->SetTitle("ADC value");
   hist01->GetYaxis()->SetNdivisions(505);
   hist01->GetYaxis()->SetLabelFont(42);
   hist01->GetYaxis()->SetLabelSize(0.07);
   hist01->GetYaxis()->SetTitleSize(0.07);
   hist01->GetYaxis()->SetTitleOffset(1.2);
   hist01->GetYaxis()->SetTitleFont(42);
   hist01->GetZaxis()->SetLabelFont(42);
   hist01->GetZaxis()->SetLabelSize(0.07);
   hist01->GetZaxis()->SetTitleSize(0.07);
   hist01->GetZaxis()->SetTitleFont(42);
   hist01->Draw("");
   
   TPaveText *pt = new TPaveText(0,0.9018323,0.416129,0.995,"blNDC");
   pt->SetName("title");
   pt->SetBorderSize(0);
   pt->SetFillColor(0);
   pt->SetFillStyle(0);
   pt->SetTextFont(42);
   TText *text = pt->AddText("Ch=38,10,07");
   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");
  
   hist01->Fit(pulse);
   c1->SaveAs("fit_waveform01.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;
}