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#include "DataFormats/Math/interface/LorentzVector.h"
#include "FastSimulation/SimplifiedGeometryPropagator/interface/StraightTrajectory.h"
#include "FastSimulation/SimplifiedGeometryPropagator/interface/HelixTrajectory.h"
#include "FastSimulation/SimplifiedGeometryPropagator/interface/ForwardSimplifiedGeometry.h"
#include "FastSimulation/SimplifiedGeometryPropagator/interface/BarrelSimplifiedGeometry.h"
#include "FastSimulation/SimplifiedGeometryPropagator/interface/Particle.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include "FastSimulation/SimplifiedGeometryPropagator/interface/Constants.h"
fastsim::Trajectory::~Trajectory() {}
fastsim::Trajectory::Trajectory(const fastsim::Particle &particle) {
position_ = particle.position();
momentum_ = particle.momentum();
}
std::unique_ptr<fastsim::Trajectory> fastsim::Trajectory::createTrajectory(const fastsim::Particle &particle,
double magneticFieldZ) {
if (particle.charge() == 0. || magneticFieldZ == 0.) {
LogDebug("FastSim") << "create straight trajectory";
return std::unique_ptr<fastsim::Trajectory>(new fastsim::StraightTrajectory(particle));
} else {
LogDebug("FastSim") << "create helix trajectory";
return std::unique_ptr<fastsim::Trajectory>(new fastsim::HelixTrajectory(particle, magneticFieldZ));
}
}
double fastsim::Trajectory::nextCrossingTimeC(const fastsim::SimplifiedGeometry &layer, bool onLayer) const {
if (layer.isForward()) {
return this->nextCrossingTimeC(static_cast<const fastsim::ForwardSimplifiedGeometry &>(layer), onLayer);
} else {
return this->nextCrossingTimeC(static_cast<const fastsim::BarrelSimplifiedGeometry &>(layer), onLayer);
}
}
double fastsim::Trajectory::nextCrossingTimeC(const fastsim::ForwardSimplifiedGeometry &layer, bool onLayer) const {
if (onLayer) {
return -1;
}
// t = (z - z_0) / v_z
// substitute: v_z = p_z / E * c ( note: extra * c absorbed in p_z units)
// => t*c = (z - z_0) / p_z * E
double deltaTimeC = (layer.getZ() - position_.Z()) / momentum_.Z() * momentum_.E();
return deltaTimeC > 0. ? deltaTimeC : -1.;
}
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