ResolutionHelper.cc File Reference

#include "DataFormats/PatCandidates/interface/ResolutionHelper.h"
#include "FWCore/Utilities/interface/Exception.h"
#include <cmath>
#include <iostream>

Go to the source code of this file.

Functions
double	DetaDtheta (double theta)
double	DthetaDeta (double eta)

Function Documentation

double DetaDtheta ( double  theta )

inline

Definition at line 443 of file ResolutionHelper.cc.

References funct::sin().

Referenced by pat::helper::ResolutionHelper::getResolEta().

                                       {
  // y  = -ln(tg(x/2)) =>
  // y' = - 1/tg(x/2) * 1/(cos(x/2))^2 * 1/2 = - 1 / (2 * sin(x/2) * cos(x/2)) = -1/sin(x)
  return -1.0 / sin(theta);
}

double DthetaDeta ( double  eta )

inline

Definition at line 448 of file ResolutionHelper.cc.

References alignCSCRings::e, and funct::exp().

Referenced by pat::helper::ResolutionHelper::getResolTheta().

                                     {
  // y = 2 atan(exp(-x))
  // y' = 2 * 1/(1+exp^2) * exp(-x) * (-1) = - 2 * exp/(1+exp^2) = - 2 / (exp + 1/exp)
  double e = exp(-eta);
  return -2.0 / (e + 1.0 / e);
}