#include <GsfMultipleScatteringUpdator.h>

Inheritance diagram for GsfMultipleScatteringUpdator:

Public Member Functions
virtual GsfMultipleScatteringUpdator *	clone () const

	GsfMultipleScatteringUpdator (float mass)
	constructor with explicit mass More...

Public Member Functions inherited from GsfMaterialEffectsUpdator
virtual std::vector < AlgebraicSymMatrix55 >	deltaLocalErrors (const TrajectoryStateOnSurface &TSoS, const PropagationDirection propDir) const

virtual std::vector< double >	deltaPs (const TrajectoryStateOnSurface &TSoS, const PropagationDirection propDir) const

	GsfMaterialEffectsUpdator (float mass)

float	mass () const

virtual TrajectoryStateOnSurface	updateState (const TrajectoryStateOnSurface &TSoS, const PropagationDirection propDir) const

virtual std::vector< double >	weights (const TrajectoryStateOnSurface &TSoS, const PropagationDirection propDir) const

virtual	~GsfMaterialEffectsUpdator ()

Protected Member Functions
virtual bool	newArguments (const TrajectoryStateOnSurface &, const PropagationDirection) const

virtual void	storeArguments (const TrajectoryStateOnSurface &, const PropagationDirection) const

Private Member Functions
virtual void	compute (const TrajectoryStateOnSurface &, const PropagationDirection) const
	Computation: generates vectors of weights, means and standard deviations. More...

Private Attributes
float	theLastDz

float	theLastP

PropagationDirection	theLastPropDir

float	theLastRadLength

Additional Inherited Members
Protected Attributes inherited from GsfMaterialEffectsUpdator
std::vector< AlgebraicSymMatrix55 >	theDeltaCovs

std::vector< double >	theDeltaPs

std::vector< double >	theWeights

Detailed Description

Description of multiple scattering with two Gaussian components as described in HEPHY-PUB 724-99. Gaussians as a function of x/X0 are parametrized as polynomials. The mixture is parametrized as a function of the thickness, velocity and Xs=X0*h(Z).

Definition at line 14 of file GsfMultipleScatteringUpdator.h.

Constructor & Destructor Documentation

GsfMultipleScatteringUpdator::GsfMultipleScatteringUpdator ( float mass )

inline

constructor with explicit mass

Definition at line 25 of file GsfMultipleScatteringUpdator.h.

Referenced by clone().

                                            :
     GsfMaterialEffectsUpdator(mass),
     theLastDz(0.),
     theLastP(0.),
     theLastPropDir(alongMomentum),
     theLastRadLength(0.) {}

Member Function Documentation

virtual GsfMultipleScatteringUpdator* GsfMultipleScatteringUpdator::clone ( void ) const

inlinevirtual

Implements GsfMaterialEffectsUpdator.

Definition at line 32 of file GsfMultipleScatteringUpdator.h.

References GsfMultipleScatteringUpdator().

   {
     return new GsfMultipleScatteringUpdator(*this);
   }

void GsfMultipleScatteringUpdator::compute	(	const TrajectoryStateOnSurface &	TSoS,
		const PropagationDirection	propDir
	)		const

privatevirtual

Computation: generates vectors of weights, means and standard deviations.

Implements GsfMaterialEffectsUpdator.

Definition at line 10 of file GsfMultipleScatteringUpdator.cc.

References h, TrajectoryStateOnSurface::localMomentum(), funct::log(), PV3DBase< T, PVType, FrameType >::mag(), GsfMaterialEffectsUpdator::mass(), Surface::mediumProperties(), L1TEmulatorMonitor_cff::p, PV3DBase< T, PVType, FrameType >::perp(), funct::pow(), MediumProperties::radLen(), mathSSE::sqrt(), storeArguments(), TrajectoryStateOnSurface::surface(), GsfMaterialEffectsUpdator::theDeltaCovs, GsfMaterialEffectsUpdator::theDeltaPs, GsfMaterialEffectsUpdator::theWeights, w2, PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), z, and PV3DBase< T, PVType, FrameType >::z().

 {
   //
   // clear cache
   //
   theWeights.clear();
   theDeltaPs.clear();
   theDeltaCovs.clear();
   //
   // Get surface and check presence of medium properties
   //
   const Surface& surface = TSoS.surface();
   //
   // calculate components
   //
   if ( surface.mediumProperties() ) {
     LocalVector pvec = TSoS.localMomentum();
     double p = TSoS.localMomentum().mag();
     pvec *= 1./p;
     // thickness in radiation lengths
     double rl = surface.mediumProperties()->radLen()/fabs(pvec.z());
     // auxiliary variables for modified X0
     const double z = 14;                 // atomic number of silicon
     const double logz = log(z);
     const double h = (z+1)/z*log(287*sqrt(z))/log(159*pow(z,-1./3.));
     double beta2 = 1./(1.+mass()*mass()/p/p);
     // reduced thickness
     double dp1 = rl/beta2/h;
     double logdp1 = log(dp1);
     double logdp2 = 2./3.*logz + logdp1;
     // means are always 0
     theDeltaPs.push_back(0.);
     theDeltaPs.push_back(0.);
     // weights
     double w2;
     if ( logdp2<log(0.5) )  
       w2 = 0.05283+0.0077*logdp2+0.00069*logdp2*logdp2;
     else
       w2 =-0.01517+0.1151*logdp2-0.00653*logdp2*logdp2;
     double w1 = 1.-w2;
     theWeights.push_back(w1);
     theWeights.push_back(w2);
     // reduced variances
     double var1 = 0.8510+0.03314*logdp1-0.001825*logdp1*logdp1;
     double var2 = (1.-w1*var1)/w2;
     for ( int ic=0; ic<2; ic++ ) {
       // choose component and multiply with total variance
       double var = ic==0 ? var1 : var2;
       var *= 225.e-6*dp1/p/p;
       AlgebraicSymMatrix55 cov;
       // transform from orthogonal planes containing the
       // momentum vector to local parameters
       double sl = pvec.perp();
       double cl = pvec.z();
       double cf = pvec.x()/sl;
       double sf = pvec.y()/sl;
       cov(1,1) = var*(sf*sf*cl*cl + cf*cf)/(cl*cl*cl*cl);
       cov(1,2) = var*(cf*sf*sl*sl        )/(cl*cl*cl*cl);
       cov(2,2) = var*(cf*cf*cl*cl + sf*sf)/(cl*cl*cl*cl);
       theDeltaCovs.push_back(cov);
     }
   }
   else {
     theWeights.push_back(1.);
     theDeltaPs.push_back(0.);
     theDeltaCovs.push_back(AlgebraicSymMatrix55());
   }
   //
   // Save arguments to avoid duplication of computation
   //
   storeArguments(TSoS,propDir); 
 }

bool GsfMultipleScatteringUpdator::newArguments	(	const TrajectoryStateOnSurface &	TSoS,
		const PropagationDirection	propDir
	)		const

protectedvirtual

Reimplemented from GsfMaterialEffectsUpdator.

Definition at line 88 of file GsfMultipleScatteringUpdator.cc.

References TrajectoryStateOnSurface::localMomentum(), PV3DBase< T, PVType, FrameType >::mag(), Surface::mediumProperties(), MediumProperties::radLen(), TrajectoryStateOnSurface::surface(), theLastDz, theLastP, theLastPropDir, theLastRadLength, Vector3DBase< T, FrameTag >::unit(), and PV3DBase< T, PVType, FrameType >::z().

                                                                   {
   return TSoS.localMomentum().unit().z()!=theLastDz ||
     TSoS.localMomentum().mag()!=theLastP || propDir!=theLastPropDir ||
     TSoS.surface().mediumProperties()->radLen()!=theLastRadLength;
 }

void GsfMultipleScatteringUpdator::storeArguments	(	const TrajectoryStateOnSurface &	TSoS,
		const PropagationDirection	propDir
	)		const

protectedvirtual

Reimplemented from GsfMaterialEffectsUpdator.

Definition at line 97 of file GsfMultipleScatteringUpdator.cc.

References TrajectoryStateOnSurface::localMomentum(), PV3DBase< T, PVType, FrameType >::mag(), Surface::mediumProperties(), MediumProperties::radLen(), TrajectoryStateOnSurface::surface(), theLastDz, theLastP, theLastPropDir, theLastRadLength, Vector3DBase< T, FrameTag >::unit(), and PV3DBase< T, PVType, FrameType >::z().

Referenced by compute().

                                                                      {
   theLastDz = TSoS.localMomentum().unit().z();
   theLastP = TSoS.localMomentum().mag();
   theLastPropDir = propDir;
   theLastRadLength = TSoS.surface().mediumProperties()->radLen();
 }