|
|
|
#include <TangentApproachInRPhi.h>
Public Member Functions | |
| virtual bool | calculate (const TrajectoryStateOnSurface &sta, const TrajectoryStateOnSurface &stb) |
| virtual bool | calculate (const FreeTrajectoryState &sta, const FreeTrajectoryState &stb) |
| virtual TangentApproachInRPhi * | clone () const |
| virtual GlobalPoint | crossingPoint () const |
| virtual float | distance () const |
| float | perpdist () const |
| virtual std::pair< GlobalPoint, GlobalPoint > | points () const |
| virtual bool | status () const |
| TangentApproachInRPhi () | |
| std::pair < GlobalTrajectoryParameters, GlobalTrajectoryParameters > | trajectoryParameters () const |
Private Member Functions | |
| bool | calculate (const TrackCharge &chargeA, const GlobalVector &momentumA, const GlobalPoint &positionA, const TrackCharge &chargeB, const GlobalVector &momentumB, const GlobalPoint &positionB, const MagneticField &magField) |
| void | circleParameters (const TrackCharge &charge, const GlobalVector &momemtum, const GlobalPoint &position, double &xc, double &yc, double &r, const MagneticField &magField) const |
| GlobalTrajectoryParameters | trajectoryParameters (const GlobalPoint &newpt, const GlobalTrajectoryParameters &oldpar) const |
| int | transverseCoord (double cxa, double cya, double ra, double cxb, double cyb, double rb, double &xg1, double &yg1, double &xg2, double &yg2) const |
| double | zCoord (const GlobalVector &mom, const GlobalPoint &pos, double r, double xc, double yc, double xg, double yg) const |
Private Attributes | |
| bool | intersection_ |
| GlobalTrajectoryParameters | paramA |
| GlobalTrajectoryParameters | paramB |
| GlobalPoint | posA |
| GlobalPoint | posB |
| bool | status_ |
Given two trajectory states, computes the two points of tangent approach in the transverse plane for the helices extrapolated from these states. 1) computes the tangent points of the circles in transverse plane. Two cases: - Whether or not the circles intersect the points used are the points of tangent approach of the two circles. 2) computes the corresponding z-coordinates.
Definition at line 15 of file TangentApproachInRPhi.h.
| TangentApproachInRPhi::TangentApproachInRPhi | ( | ) | [inline] |
Definition at line 19 of file TangentApproachInRPhi.h.
References intersection_, and status_.
Referenced by clone().
{status_ = false; intersection_ = false;}
| bool TangentApproachInRPhi::calculate | ( | const TrajectoryStateOnSurface & | sta, |
| const TrajectoryStateOnSurface & | stb | ||
| ) | [virtual] |
Implements ClosestApproachOnHelices.
Definition at line 8 of file TangentApproachInRPhi.cc.
References TrajectoryStateOnSurface::charge(), TrajectoryStateOnSurface::freeState(), TrajectoryStateOnSurface::globalMomentum(), TrajectoryStateOnSurface::globalParameters(), TrajectoryStateOnSurface::globalPosition(), GlobalTrajectoryParameters::magneticField(), and FreeTrajectoryState::parameters().
Referenced by TrackerOnlyConversionProducer::preselectTrackPair().
{
TrackCharge chargeA = sta.charge(); TrackCharge chargeB = stb.charge();
GlobalVector momentumA = sta.globalMomentum();
GlobalVector momentumB = stb.globalMomentum();
GlobalPoint positionA = sta.globalPosition();
GlobalPoint positionB = stb.globalPosition();
paramA = sta.globalParameters();
paramB = stb.globalParameters();
return calculate(chargeA, momentumA, positionA, chargeB, momentumB, positionB,
sta.freeState()->parameters().magneticField());
}
| bool TangentApproachInRPhi::calculate | ( | const FreeTrajectoryState & | sta, |
| const FreeTrajectoryState & | stb | ||
| ) | [virtual] |
Implements ClosestApproachOnHelices.
Definition at line 24 of file TangentApproachInRPhi.cc.
References FreeTrajectoryState::charge(), GlobalTrajectoryParameters::magneticField(), FreeTrajectoryState::momentum(), FreeTrajectoryState::parameters(), and FreeTrajectoryState::position().
{
TrackCharge chargeA = sta.charge(); TrackCharge chargeB = stb.charge();
GlobalVector momentumA = sta.momentum();
GlobalVector momentumB = stb.momentum();
GlobalPoint positionA = sta.position();
GlobalPoint positionB = stb.position();
paramA = sta.parameters();
paramB = stb.parameters();
return calculate(chargeA, momentumA, positionA, chargeB, momentumB, positionB,
sta.parameters().magneticField());
}
| bool TangentApproachInRPhi::calculate | ( | const TrackCharge & | chargeA, |
| const GlobalVector & | momentumA, | ||
| const GlobalPoint & | positionA, | ||
| const TrackCharge & | chargeB, | ||
| const GlobalVector & | momentumB, | ||
| const GlobalPoint & | positionB, | ||
| const MagneticField & | magField | ||
| ) | [private] |
Definition at line 81 of file TangentApproachInRPhi.cc.
{
// centres and radii of track circles
double xca, yca, ra;
circleParameters(chargeA, momentumA, positionA, xca, yca, ra, magField);
double xcb, ycb, rb;
circleParameters(chargeB, momentumB, positionB, xcb, ycb, rb, magField);
// points of closest approach in transverse plane
double xg1, yg1, xg2, yg2;
int flag = transverseCoord(xca, yca, ra, xcb, ycb, rb, xg1, yg1, xg2, yg2);
if (flag == 0) {
status_ = false;
return false;
}
double xga, yga, zga, xgb, ygb, zgb;
if (flag == 1) {
intersection_ = true;
}
else {
intersection_ = false;
}
// one point of closest approach on each track in transverse plane
xga = xg1; yga = yg1;
zga = zCoord(momentumA, positionA, ra, xca, yca, xga, yga);
xgb = xg2; ygb = yg2;
zgb = zCoord(momentumB, positionB, rb, xcb, ycb, xgb, ygb);
posA = GlobalPoint(xga, yga, zga);
posB = GlobalPoint(xgb, ygb, zgb);
status_ = true;
return true;
}
| void TangentApproachInRPhi::circleParameters | ( | const TrackCharge & | charge, |
| const GlobalVector & | momemtum, | ||
| const GlobalPoint & | position, | ||
| double & | xc, | ||
| double & | yc, | ||
| double & | r, | ||
| const MagneticField & | magField | ||
| ) | const [private] |
temporary code, to be replaced by call to curvature() when bug is fixed.
end of temporary code
Definition at line 166 of file TangentApproachInRPhi.cc.
References abs, funct::cos(), MagneticField::inTesla(), PV3DBase< T, PVType, FrameType >::phi(), phi, funct::sin(), PV3DBase< T, PVType, FrameType >::transverse(), PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), and PV3DBase< T, PVType, FrameType >::z().
{
// compute radius of circle
// double bz = MagneticField::inInverseGeV(position).z();
double bz = magField.inTesla(position).z() * 2.99792458e-3;
// signed_r directed towards circle center, along F_Lorentz = q*v X B
double signed_r = charge*momentum.transverse() / bz;
r = abs(signed_r);
// compute centre of circle
double phi = momentum.phi();
xc = signed_r*sin(phi) + position.x();
yc = -signed_r*cos(phi) + position.y();
}
| virtual TangentApproachInRPhi* TangentApproachInRPhi::clone | ( | void | ) | const [inline, virtual] |
Clone method
Implements ClosestApproachOnHelices.
Definition at line 51 of file TangentApproachInRPhi.h.
References TangentApproachInRPhi().
{
return new TangentApproachInRPhi(* this);
}
| GlobalPoint TangentApproachInRPhi::crossingPoint | ( | ) | const [virtual] |
arithmetic mean of the two points of closest approach
Implements ClosestApproachOnHelices.
Definition at line 48 of file TangentApproachInRPhi.cc.
References Exception.
Referenced by TrackerOnlyConversionProducer::preselectTrackPair().
| float TangentApproachInRPhi::distance | ( | ) | const [virtual] |
distance between the two points of closest approach in 3D
Implements ClosestApproachOnHelices.
Definition at line 58 of file TangentApproachInRPhi.cc.
References Exception.
{
if (!status_)
throw cms::Exception("TrackingTools/PatternTools","TangentApproachInRPhi::could not compute track crossing. Check status before calling this method!");
return (posB - posA).mag();
}
| float TangentApproachInRPhi::perpdist | ( | ) | const |
signed distance between two points of closest approach in r-phi plane (-ive if circles intersect)
Definition at line 65 of file TangentApproachInRPhi.cc.
References Exception, and perp().
Referenced by TrackerOnlyConversionProducer::preselectTrackPair().
{
if (!status_)
throw cms::Exception("TrackingTools/PatternTools","TangentApproachInRPhi::could not compute track crossing. Check status before calling this method!");
float perpdist = (posB - posA).perp();
if (intersection_) {
perpdist = -perpdist;
}
return perpdist;
}
| pair< GlobalPoint, GlobalPoint > TangentApproachInRPhi::points | ( | ) | const [virtual] |
Returns the two PCA on the trajectories.
Implements ClosestApproachOnHelices.
Definition at line 39 of file TangentApproachInRPhi.cc.
References Exception.
{
if (!status_)
throw cms::Exception("TrackingTools/PatternTools","TangentApproachInRPhi::could not compute track crossing. Check status before calling this method!");
return pair<GlobalPoint, GlobalPoint> (posA, posB);
}
| virtual bool TangentApproachInRPhi::status | ( | void | ) | const [inline, virtual] |
Implements ClosestApproachOnHelices.
Definition at line 27 of file TangentApproachInRPhi.h.
References status_.
Referenced by TrackerOnlyConversionProducer::preselectTrackPair().
{return status_;}
| pair< GlobalTrajectoryParameters, GlobalTrajectoryParameters > TangentApproachInRPhi::trajectoryParameters | ( | ) | const |
Returns not only the points, but the full GlobalTrajectoryParemeters at the points of closest approach
Definition at line 127 of file TangentApproachInRPhi.cc.
References Exception, and runTheMatrix::ret.
Referenced by TrackerOnlyConversionProducer::preselectTrackPair().
{
if (!status_)
throw cms::Exception("TrackingTools/PatternTools","TangentApproachInRPhi::could not compute track crossing. Check status before calling this method!");
pair <GlobalTrajectoryParameters, GlobalTrajectoryParameters>
ret ( trajectoryParameters ( posA, paramA ),
trajectoryParameters ( posB, paramB ) );
return ret;
}
| GlobalTrajectoryParameters TangentApproachInRPhi::trajectoryParameters | ( | const GlobalPoint & | newpt, |
| const GlobalTrajectoryParameters & | oldpar | ||
| ) | const [private] |
Definition at line 137 of file TangentApproachInRPhi.cc.
References GlobalTrajectoryParameters::charge(), GlobalTrajectoryParameters::magneticField(), GlobalTrajectoryParameters::momentum(), GlobalTrajectoryParameters::position(), csvReporter::r, mathSSE::sqrt(), PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), and PV3DBase< T, PVType, FrameType >::z().
{
// First we need the centers of the circles.
double xc, yc, r;
circleParameters( oldgtp.charge(), oldgtp.momentum(),
oldgtp.position(), xc, yc, r, oldgtp.magneticField() );
// now we do a translation, move the center of circle to (0,0,0).
double dx1 = oldgtp.position().x() - xc;
double dy1 = oldgtp.position().y() - yc;
double dx2 = newpt.x() - xc;
double dy2 = newpt.y() - yc;
// now for the angles:
double cosphi = ( dx1 * dx2 + dy1 * dy2 ) /
( sqrt ( dx1 * dx1 + dy1 * dy1 ) * sqrt ( dx2 * dx2 + dy2 * dy2 ));
double sinphi = - oldgtp.charge() * sqrt ( 1 - cosphi * cosphi );
// Finally, the new momenta:
double px = cosphi * oldgtp.momentum().x() - sinphi * oldgtp.momentum().y();
double py = sinphi * oldgtp.momentum().x() + cosphi * oldgtp.momentum().y();
GlobalVector vta ( px, py, oldgtp.momentum().z() );
GlobalTrajectoryParameters gta( newpt , vta , oldgtp.charge(), &(oldgtp.magneticField()) );
return gta;
}
| int TangentApproachInRPhi::transverseCoord | ( | double | cxa, |
| double | cya, | ||
| double | ra, | ||
| double | cxb, | ||
| double | cyb, | ||
| double | rb, | ||
| double & | xg1, | ||
| double & | yg1, | ||
| double & | xg2, | ||
| double & | yg2 | ||
| ) | const [private] |
Definition at line 196 of file TangentApproachInRPhi.cc.
References abs, mathSSE::sqrt(), and v.
{
int flag = 0;
double x1, y1, x2, y2;
// new reference frame with origin in (cxa, cya) and x-axis
// directed from (cxa, cya) to (cxb, cyb)
double d_ab = sqrt((cxb - cxa)*(cxb - cxa) + (cyb - cya)*(cyb - cya));
if (d_ab == 0) { // concentric circles
return 0;
}
// elements of rotation matrix
double u = (cxb - cxa) / d_ab;
double v = (cyb - cya) / d_ab;
// conditions for circle intersection
if (d_ab <= ra + rb && d_ab >= abs(rb - ra)) {
// circles cross each other
// flag = 1;
//
// // triangle (ra, rb, d_ab)
// double cosphi = (ra*ra - rb*rb + d_ab*d_ab) / (2*ra*d_ab);
// double sinphi2 = 1. - cosphi*cosphi;
// if (sinphi2 < 0.) { sinphi2 = 0.; cosphi = 1.; }
//
// // intersection points in new frame
// double sinphi = sqrt(sinphi2);
// x1 = ra*cosphi; y1 = ra*sinphi; x2 = x1; y2 = -y1;
//circles cross each other, but take tangent points anyway
flag = 1;
// points of closest approach in new frame
// are on line between 2 centers
x1 = ra; y1 = 0; x2 = d_ab - rb; y2 = 0;
}
else if (d_ab > ra + rb) {
// circles are external to each other
flag = 2;
// points of closest approach in new frame
// are on line between 2 centers
x1 = ra; y1 = 0; x2 = d_ab - rb; y2 = 0;
}
else if (d_ab < abs(rb - ra)) {
// circles are inside each other
flag = 2;
// points of closest approach in new frame are on line between 2 centers
// choose 2 closest points
double sign = 1.;
if (ra <= rb) sign = -1.;
x1 = sign*ra; y1 = 0; x2 = d_ab + sign*rb; y2 = 0;
}
else {
return 0;
}
// intersection points in global frame, transverse plane
xg1 = u*x1 - v*y1 + cxa; yg1 = v*x1 + u*y1 + cya;
xg2 = u*x2 - v*y2 + cxa; yg2 = v*x2 + u*y2 + cya;
return flag;
}
| double TangentApproachInRPhi::zCoord | ( | const GlobalVector & | mom, |
| const GlobalPoint & | pos, | ||
| double | r, | ||
| double | xc, | ||
| double | yc, | ||
| double | xg, | ||
| double | yg | ||
| ) | const [private] |
Definition at line 272 of file TangentApproachInRPhi.cc.
References abs, phi, csvReporter::r, mathSSE::sqrt(), PV3DBase< T, PVType, FrameType >::transverse(), ExpressReco_HICollisions_FallBack::x, PV3DBase< T, PVType, FrameType >::x(), ExpressReco_HICollisions_FallBack::y, PV3DBase< T, PVType, FrameType >::y(), PV3DBase< T, PVType, FrameType >::z(), and z.
{
// starting point
double x = pos.x(); double y = pos.y(); double z = pos.z();
double px = mom.x(); double py = mom.y(); double pz = mom.z();
// rotation angle phi from starting point to crossing point (absolute value)
// -- compute sin(phi/2) if phi smaller than pi/4,
// -- cos(phi) if phi larger than pi/4
double phi = 0.;
double sinHalfPhi = sqrt((x-xg)*(x-xg) + (y-yg)*(y-yg))/(2*r);
if (sinHalfPhi < 0.383) { // sin(pi/8)
phi = 2*asin(sinHalfPhi);
}
else {
double cosPhi = ((x-xc)*(xg-xc) + (y-yc)*(yg-yc))/(r*r);
if (std::abs(cosPhi) > 1) cosPhi = (cosPhi > 0 ? 1 : -1);
phi = abs(acos(cosPhi));
}
// -- sign of phi
double signPhi = ((x - xc)*(yg - yc) - (xg - xc)*(y - yc) > 0) ? 1. : -1.;
// sign of track angular momentum
// if rotation is along angular momentum, delta z is along pz
double signOmega = ((x - xc)*py - (y - yc)*px > 0) ? 1. : -1.;
// delta z
// -- |dz| = |cos(theta) * path along helix|
// = |cos(theta) * arc length along circle / sin(theta)|
double dz = signPhi*signOmega*(pz/mom.transverse())*phi*r;
return z + dz;
}
bool TangentApproachInRPhi::intersection_ [private] |
Definition at line 100 of file TangentApproachInRPhi.h.
Referenced by TangentApproachInRPhi().
Definition at line 99 of file TangentApproachInRPhi.h.
Definition at line 99 of file TangentApproachInRPhi.h.
GlobalPoint TangentApproachInRPhi::posA [private] |
Definition at line 98 of file TangentApproachInRPhi.h.
GlobalPoint TangentApproachInRPhi::posB [private] |
Definition at line 98 of file TangentApproachInRPhi.h.
bool TangentApproachInRPhi::status_ [private] |
Definition at line 97 of file TangentApproachInRPhi.h.
Referenced by status(), and TangentApproachInRPhi().
1.7.3