SCT_LorentzAngleFunc.h File Reference

#include <cmath>
#include "RtypesCore.h"

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Functions
Double_t	LA_func (Double_t *x, Double_t *par)

Function Documentation

LA_func()

Double_t LA_func	(	Double_t *	x,
		Double_t *	par
	)

Definition at line 11 of file SCT_LorentzAngleFunc.h.

                                    {
  const Int_t n{1000}; // number of integration step
  const Double_t xmin{x[0] - 5.0*par[3]};
  const Double_t xmax{x[0] + 5.0*par[3]};
  const Double_t h{(xmax - xmin)/(n - 1)};
  const double piOver180 = M_PI/180.;
  const double piNorm = 1./std::sqrt(2.*M_PI);
  Double_t sum{0.};
  Double_t x_{xmin};
  Double_t LA_sum{0.};
  for (Int_t i{1}; i<n; i++) {
    LA_sum = par[0]*std::abs(std::tan(x_*piOver180)-std::tan(par[1]*piOver180))+par[2];
    sum += LA_sum * 0.017455 * piNorm/(par[3]*piOver180)
      * std::exp(-(x[0]*piOver180 - x_*piOver180 )*(x[0]*piOver180 - x_*piOver180 )/(2*par[3]*piOver180*par[3]*piOver180)) * h;
    x_ += h;
  }
  return sum;
}