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#include <FastHelix.h>
Public Member Functions | |
| FastHelix (const GlobalPoint &outerHit, const GlobalPoint &middleHit, const GlobalPoint &aVertex, const edm::EventSetup &iSetup) | |
| FastHelix (const GlobalPoint &outerHit, const GlobalPoint &middleHit, const GlobalPoint &aVertex, const edm::EventSetup &iSetup, const GlobalPoint &bVertex) | |
| FTS | helixStateAtVertex () const |
| bool | isValid () const |
| FTS | stateAtVertex () const |
| FTS | straightLineStateAtVertex () const |
| ~FastHelix () | |
Private Types | |
| typedef FreeTrajectoryState | FTS |
Private Attributes | |
| GlobalPoint | basisVertex |
| edm::ESHandle< MagneticField > | pSetup |
| GlobalVector | tesla0 |
| FastCircle | theCircle |
| GlobalPoint | theMiddleHit |
| GlobalPoint | theOuterHit |
| GlobalPoint | theVertex |
| bool | useBasisVertex |
Generation of track parameters at a vertex using two hits and a vertex. It is used e.g. by a seed generator.
21.02.2001: Old FastHelix is now called FastHelixFit. Replace FastLineFit by FastLine (z0, dz/drphi calculated without vertex and errors) 14.02.2001: Replace general Circle by FastCircle. 13.02.2001: LinearFitErrorsInTwoCoordinates replaced by FastLineFit 29.11.2000: (Pascal Vanlaer) Modification of calculation of sign of px,py and change in calculation of pz, z0. 29.11.2000: (Matthias Winkler) Split stateAtVertex() in two parts (Circle is valid or not): helixStateAtVertex() and straightLineStateAtVertex()
Definition at line 27 of file FastHelix.h.
typedef FreeTrajectoryState FastHelix::FTS [private] |
Definition at line 31 of file FastHelix.h.
| FastHelix::FastHelix | ( | const GlobalPoint & | outerHit, |
| const GlobalPoint & | middleHit, | ||
| const GlobalPoint & | aVertex, | ||
| const edm::EventSetup & | iSetup | ||
| ) | [inline] |
Definition at line 37 of file FastHelix.h.
References edm::EventSetup::get(), pSetup, tesla0, and useBasisVertex.
: theOuterHit(outerHit), theMiddleHit(middleHit), theVertex(aVertex), theCircle(outerHit, middleHit, aVertex) { iSetup.get<IdealMagneticFieldRecord>().get(pSetup); tesla0=pSetup->inTesla(GlobalPoint(0,0,0)); useBasisVertex = false; }
| FastHelix::FastHelix | ( | const GlobalPoint & | outerHit, |
| const GlobalPoint & | middleHit, | ||
| const GlobalPoint & | aVertex, | ||
| const edm::EventSetup & | iSetup, | ||
| const GlobalPoint & | bVertex | ||
| ) | [inline] |
Definition at line 52 of file FastHelix.h.
References edm::EventSetup::get(), pSetup, tesla0, and useBasisVertex.
: theOuterHit(outerHit), theMiddleHit(middleHit), theVertex(aVertex), basisVertex(bVertex), theCircle(outerHit, middleHit, aVertex) { iSetup.get<IdealMagneticFieldRecord>().get(pSetup); tesla0=pSetup->inTesla(GlobalPoint(0,0,0)); useBasisVertex = true; }
| FastHelix::~FastHelix | ( | ) | [inline] |
Definition at line 68 of file FastHelix.h.
{}
| FreeTrajectoryState FastHelix::helixStateAtVertex | ( | ) | const |
Definition at line 16 of file FastHelix.cc.
References basisVertex, funct::C, FastCircle::n1(), FastLine::n1(), FastCircle::n2(), pSetup, lumiQueryAPI::q, FastCircle::rho(), rho, mathSSE::sqrt(), tesla0, theCircle, theMiddleHit, theOuterHit, theVertex, useBasisVertex, v, PV3DBase< T, PVType, FrameType >::x(), FastCircle::x0(), PV3DBase< T, PVType, FrameType >::y(), FastCircle::y0(), and PV3DBase< T, PVType, FrameType >::z().
Referenced by stateAtVertex().
{
GlobalPoint pMid(theMiddleHit);
GlobalPoint v(theVertex);
double dydx = 0., dxdy = 0.;
double pt = 0., px = 0., py = 0.;
//remember (radius rho in cm):
//rho =
//100. * pt *
//(10./(3.*MagneticField::inTesla(GlobalPoint(0., 0., 0.)).z()));
double rho = theCircle.rho();
// pt = 0.01 * rho * (0.3*MagneticField::inTesla(GlobalPoint(0.,0.,0.)).z());
pt = 0.01 * rho * (0.3*tesla0.z());
// pt = 0.01 * rho * (0.3*GlobalPoint(0.,0.,0.).MagneticField().z());
// (py/px)|x=v.x() = (dy/dx)|x=v.x()
//remember:
//y(x) = +-sqrt(rho^2 - (x-x0)^2) + y0
//y(x) = sqrt(rho^2 - (x-x0)^2) + y0 if y(x) >= y0
//y(x) = -sqrt(rho^2 - (x-x0)^2) + y0 if y(x) < y0
//=> (dy/dx) = -(x-x0)/sqrt(Q) if y(x) >= y0
// (dy/dx) = (x-x0)/sqrt(Q) if y(x) < y0
//with Q = rho^2 - (x-x0)^2
// Check approximate slope to determine whether to use dydx or dxdy
// Choose the one that goes to 0 rather than infinity.
double arg1 = rho*rho - (v.x()-theCircle.x0())*(v.x()-theCircle.x0());
double arg2 = rho*rho - (v.y()-theCircle.y0())*(v.y()-theCircle.y0());
if (arg1<0.0 && arg2<0.0) {
if(fabs(theCircle.n2()) > 0.) {
dydx = -theCircle.n1()/theCircle.n2(); //else px = 0
px = pt/sqrt(1. + dydx*dydx);
py = px*dydx;
} else {
px = 0.;
py = pt;
}
} else if ( arg1>arg2 ) {
if( v.y() > theCircle.y0() )
dydx = -(v.x() - theCircle.x0()) / sqrt(arg1);
else
dydx = (v.x() - theCircle.x0()) / sqrt(arg1);
px = pt/sqrt(1. + dydx*dydx);
py = px*dydx;
} else {
if( v.x() > theCircle.x0() )
dxdy = -(v.y() - theCircle.y0()) / sqrt(arg2);
else
dxdy = (v.y() - theCircle.y0()) / sqrt(arg2);
py = pt/sqrt(1. + dxdy*dxdy);
px = py*dxdy;
}
// check sign with scalar product
if(px*(pMid.x() - v.x()) + py*(pMid.y() - v.y()) < 0.) {
px *= -1.;
py *= -1.;
}
//calculate z0, pz
//(z, R*phi) linear relation in a helix
//with R, phi defined as radius and angle w.r.t. centre of circle
//in transverse plane
//pz = pT*(dz/d(R*phi)))
FastLine flfit(theOuterHit, theMiddleHit, theCircle.rho());
double dzdrphi = -flfit.n1()/flfit.n2();
double pz = pt*dzdrphi;
//get sign of particle
GlobalVector magvtx=pSetup->inTesla(v);
TrackCharge q =
((theCircle.x0()*py - theCircle.y0()*px) /
(magvtx.z()) < 0.) ?
-1 : 1;
AlgebraicSymMatrix C(5,1);
//MP
if ( useBasisVertex ) {
return FTS(GlobalTrajectoryParameters(basisVertex,
GlobalVector(px, py, pz),
q,
&(*pSetup)),
CurvilinearTrajectoryError(C));
} else {
double z_0 = -flfit.c()/flfit.n2();
return FTS(GlobalTrajectoryParameters(GlobalPoint(v.x(),v.y(),z_0),
GlobalVector(px, py, pz),
q,
&(*pSetup)),
CurvilinearTrajectoryError(C));
}
}
| bool FastHelix::isValid | ( | void | ) | const [inline] |
Definition at line 70 of file FastHelix.h.
References FastCircle::isValid(), and theCircle.
Referenced by SiStripElectronSeedGenerator::altCheckHitsAndTSOS(), SiStripElectronSeedGenerator::checkHitsAndTSOS(), RoadSearchTrackCandidateMakerAlgorithm::initialTrajectory(), RoadSearchTrackCandidateMakerAlgorithm::initialTrajectoryFromTriplet(), and stateAtVertex().
| FreeTrajectoryState FastHelix::stateAtVertex | ( | ) | const |
Definition at line 7 of file FastHelix.cc.
References helixStateAtVertex(), isValid(), straightLineStateAtVertex(), tesla0, and PV3DBase< T, PVType, FrameType >::z().
Referenced by SiStripElectronSeedGenerator::altCheckHitsAndTSOS(), SiStripElectronSeedGenerator::checkHitsAndTSOS(), SiStripElectronSeedGenerator::findSeedsFromCluster(), RoadSearchTrackCandidateMakerAlgorithm::initialTrajectory(), RoadSearchTrackCandidateMakerAlgorithm::initialTrajectoryFromTriplet(), SimpleCosmicBONSeeder::pqFromHelixFit(), ConvBremSeedProducer::produce(), SeedFromGenericPairOrTriplet::seedFromTriplet(), and SeedGeneratorForCosmics::seeds().
{
if(isValid() && (fabs(tesla0.z()) > 1e-3))
return helixStateAtVertex();
else
return straightLineStateAtVertex();
}
| FreeTrajectoryState FastHelix::straightLineStateAtVertex | ( | ) | const |
Definition at line 113 of file FastHelix.cc.
References basisVertex, funct::C, FastLine::c(), FastCircle::n1(), FastLine::n1(), FastCircle::n2(), FastLine::n2(), pSetup, lumiQueryAPI::q, mathSSE::sqrt(), theCircle, theMiddleHit, theOuterHit, theVertex, useBasisVertex, v, PV3DBase< T, PVType, FrameType >::x(), and PV3DBase< T, PVType, FrameType >::y().
Referenced by stateAtVertex().
{
//calculate FTS assuming straight line...
GlobalPoint pMid(theMiddleHit);
GlobalPoint v(theVertex);
double dydx = 0.;
double pt = 0., px = 0., py = 0.;
if(fabs(theCircle.n1()) > 0. || fabs(theCircle.n2()) > 0.)
pt = 1.e+4;// 10 TeV //else no pt
if(fabs(theCircle.n2()) > 0.) {
dydx = -theCircle.n1()/theCircle.n2(); //else px = 0
}
px = pt/sqrt(1. + dydx*dydx);
py = px*dydx;
// check sign with scalar product
if (px*(pMid.x() - v.x()) + py*(pMid.y() - v.y()) < 0.) {
px *= -1.;
py *= -1.;
}
//calculate z_0 and pz at vertex using weighted mean
//z = z(r) = z0 + (dz/dr)*r
//tan(theta) = dr/dz = (dz/dr)^-1
//theta = atan(1./dzdr)
//p = pt/sin(theta)
//pz = p*cos(theta) = pt/tan(theta)
FastLine flfit(theOuterHit, theMiddleHit);
double dzdr = -flfit.n1()/flfit.n2();
double pz = pt*dzdr;
TrackCharge q = 1;
AlgebraicSymMatrix66 C = AlgebraicMatrixID();
//MP
if ( useBasisVertex ) {
return FTS(GlobalTrajectoryParameters(basisVertex,
GlobalVector(px, py, pz),
q,
&(*pSetup)),
CartesianTrajectoryError(C));
} else {
double z_0 = -flfit.c()/flfit.n2();
return FTS(GlobalTrajectoryParameters(GlobalPoint(v.x(), v.y(), z_0),
GlobalVector(px, py, pz),
q,
&(*pSetup)),
CartesianTrajectoryError());
}
}
GlobalPoint FastHelix::basisVertex [private] |
Definition at line 83 of file FastHelix.h.
Referenced by helixStateAtVertex(), and straightLineStateAtVertex().
edm::ESHandle<MagneticField> FastHelix::pSetup [private] |
Definition at line 85 of file FastHelix.h.
Referenced by FastHelix(), helixStateAtVertex(), and straightLineStateAtVertex().
GlobalVector FastHelix::tesla0 [private] |
Definition at line 86 of file FastHelix.h.
Referenced by FastHelix(), helixStateAtVertex(), and stateAtVertex().
FastCircle FastHelix::theCircle [private] |
Definition at line 84 of file FastHelix.h.
Referenced by helixStateAtVertex(), isValid(), and straightLineStateAtVertex().
GlobalPoint FastHelix::theMiddleHit [private] |
Definition at line 81 of file FastHelix.h.
Referenced by helixStateAtVertex(), and straightLineStateAtVertex().
GlobalPoint FastHelix::theOuterHit [private] |
Definition at line 80 of file FastHelix.h.
Referenced by helixStateAtVertex(), and straightLineStateAtVertex().
GlobalPoint FastHelix::theVertex [private] |
Definition at line 82 of file FastHelix.h.
Referenced by helixStateAtVertex(), and straightLineStateAtVertex().
bool FastHelix::useBasisVertex [private] |
Definition at line 87 of file FastHelix.h.
Referenced by FastHelix(), helixStateAtVertex(), and straightLineStateAtVertex().
1.7.3