#draw_laser_profile.C#

Double_t laser_profile(Double_t *x, Double_t *par)
{
   double a = TMath::Cos(par[4])*TMath::Cos(par[3]),
     b = TMath::Sin(par[4]),
     c = TMath::Cos(par[4])*TMath::Sin(par[3])/par[1],
     d = (-TMath::Cos(par[4])*TMath::Sin(par[3])*par[0]+par[2]*TMath::Sin(par[4]))/par[1];
   double gamma = TMath::Sqrt(a*a+b*b),
     delta = TMath::ATan2(b,a);
   double phi = ((TMath::ASin((c*(-x[0]+576)+d/gamma)-delta) + par[5])*TMath::RadToDeg())/11.25;
   // double phimax = TMath::Cos(par[1]/par[2]) + par[5];
   // if( phi > phimax ) return 0.;
   return phi;
}

void draw_laser_profile()
{
  // z0 -> par[0]
  // Rc -> par[1]
  // Rr -> par[2]
  // theta -> par[3]
  // beta -> par[4]
  // off_phi -> par[5] 
  
  //double z0 = -5.125, Rc = 315.3, Rr = Rc + 294.8375, // rows

  //double z0 = -5.125, Rc = 109.2, Rr = Rc + 27.35, // mm
   double z0 = 581.125, Rc = 109.2, Rr = Rc + 27.35, // mm

    theta = -3.0*TMath::DegToRad(), beta = -50.*TMath::DegToRad();
  double off_phi = 0*TMath::DegToRad();
  double zmin=0., zmax=576.; // mm
  //double zmin=0., zmax=576.; // mm
  TF1* f1 = new TF1("laser_profile_1",laser_profile,zmin,zmax,6);
  f1->SetParameters(z0,Rc,Rr,theta,beta,off_phi);
  f1->SetParNames("z0","Rc","Rr","theta","beta");
  f1->Draw();
}