Lpar.cxx File Reference

#include <iostream>
#include <cmath>
#include "TrackUtil/Lpar.h"

Go to the source code of this file.

Functions
int	intersect (const Lpar &lp1, const Lpar &lp2, HepVector &v1, HepVector &v2)
std::ostream &	operator<< (std::ostream &o, Lpar &s)

Function Documentation

intersect()

int intersect	(	const Lpar &	lp1,
		const Lpar &	lp2,
		HepVector &	v1,
		HepVector &	v2 )

Definition at line 243 of file TrackUtil/TrackUtil-00-00-12/src/Lpar.cxx.

                                                                          {
  HepVector cen1(lp1.center());
  HepVector cen2(lp2.center());
  double dx = cen1(1)-cen2(1);
  double dy = cen1(2)-cen2(2);
  double dc = sqrt(dx*dx+dy*dy);
  if(dc<fabs(0.5/lp1.kappa())+fabs(0.5/lp2.kappa())) {
    double a1 = std::sqrt(lp1.alpha()) + std::sqrt(lp1.beta());
    double a2 = std::sqrt(lp2.alpha()) + std::sqrt(lp2.beta());
    double a3 = lp1.alpha()*lp2.alpha() + lp1.beta()*lp2.beta();
    double det = lp1.alpha()*lp2.beta() - lp1.beta()*lp2.alpha();
    if(fabs(det)>1e-12) {
      double c1 = a2 * std::sqrt(lp1.kappa()) + a1 * std::sqrt(lp2.kappa()) -
        2.0 * a3 * lp1.kappa() * lp2.kappa();
      if(c1!=0) {
        double cinv = 1.0 / c1;
        double c2 = std::sqrt(a3) - 0.5 * (a1 + a2) - 2.0 * a3 *
          (lp1.gamma() * lp2.kappa() + lp2.gamma() * lp1.kappa());
        double c3 = a2 * std::sqrt(lp1.gamma()) + a1 * std::sqrt(lp2.gamma()) -
          2.0 * a3 * lp1.gamma() * lp2.gamma();
        double root = std::sqrt(c2) - 4.0 * c1 * c3;
        if (root>=0) {
          root = sqrt(root);
          double rad2[2];
          rad2[0] = 0.5 * cinv * (-c2 - root);
          rad2[1] = 0.5 * cinv * (-c2 + root);
          double ab1 = -(lp2.beta() * lp1.gamma() - lp1.beta() * lp2.gamma());
          double ab2 = (lp2.alpha() * lp1.gamma() - lp1.alpha() * lp2.gamma());
          double ac1 = -(lp2.beta() * lp1.kappa() - lp1.beta() * lp2.kappa());
          double ac2 = (lp2.alpha() * lp1.kappa() - lp1.alpha() * lp2.kappa());
          double dinv = 1.0 / det;
          v1(1) = dinv * (ab1 + ac1 * rad2[0]);
          v1(2) = dinv * (ab2 + ac2 * rad2[0]);
          v1(3) = 0;
          v2(1) = dinv * (ab1 + ac1 * rad2[1]);
          v2(2) = dinv * (ab2 + ac2 * rad2[1]);
          v2(3) = 0;
      double d1 = lp1.d(v1(1),v1(2));
      double d2 = lp2.d(v1(1),v1(2));
      double d3 = lp1.d(v2(1),v2(2));
      double d4 = lp2.d(v2(1),v2(2));
          double r = sqrt(rad2[0]);
          Lpar::Cpar cp1(lp1);
          Lpar::Cpar cp2(lp2);
      for(int j=0;j<2;j++) {
        double s1,s2;
        if(j==0) {
          s1 = lp1.s(v1(1),v1(2));
          s2 = lp2.s(v1(1),v1(2));
        } else {
          s1 = lp1.s(v2(1),v2(2));
          s2 = lp2.s(v2(1),v2(2));
        }
        double phi1 = cp1.fi() + 2 * cp1.cu() * s1;
        double phi2 = cp2.fi() + 2 * cp2.cu() * s2;
        double f = (1 + 2 * cp1.cu() * cp1.da()) *
          (1 + 2 * cp2.cu() * cp2.da()) * cos(cp1.fi()-cp2.fi());
        f -= 2 * (lp1.gamma() * lp2.kappa() + lp2.gamma() * lp1.kappa());
        double cosphi12 = f;
      }
      return 2;
        }
      }
    }
  }
  return 0;
}

operator<<()

std::ostream & operator<<	(	std::ostream &	o,
		Lpar &	s )

Definition at line 319 of file TrackUtil/TrackUtil-00-00-12/src/Lpar.cxx.

                                               {
  return o << " al=" << s.m_alpha << " be=" << s.m_beta
           << " ka=" << s.m_kappa << " ga=" << s.m_gamma;
}