VXDElectronDeposit Class Reference

Packed class to represent energy deposit along a path in electrons. More...

#include <VXDElectronDeposit.h>

Public Types
enum	EBits {   c_FractionBits = 10 ,   c_ElectronBits = 22 ,   c_TotalBits = c_FractionBits + c_ElectronBits ,   c_MaxFraction = (1 << c_FractionBits) - 1 ,   c_MaxElectrons = (1 << c_ElectronBits) - 1 }
	Enum storing the bit informations for the packed information. More...

Public Member Functions
	VXDElectronDeposit (unsigned int packed)
	Create a new instance from a packed value.
	VXDElectronDeposit (float fraction, float electrons)
	create a new instance from a fraction along the path and a number of electrons.
float	getFraction () const
	get the fraction along the path
unsigned int	getElectrons () const
	get the number of deposited electrons
unsigned int	getPacked () const
	get the packed value
	operator unsigned int () const
	convert to unsigned int using the packed representation

Private Attributes
unsigned int	m_packed: c_TotalBits
	packed representation of the fraction and electron deposition

Detailed Description

Packed class to represent energy deposit along a path in electrons.

This class is used by the VXD to efficiently store the number of electrons deposited in the silicon along a given path by storing the fraction along the path and the number of electrons at that point in a packed way. The fraction is encoded between 0 and 1 using 8 bits and the number of electrons is stored as 24bit unsigned integer which allows for 16.7 million electrons per step. As the electron hole pair production energy is 3eV in silicon this corresponds to an energy loss of around 50GeV so there should be no problem at all.

Definition at line 32 of file VXDElectronDeposit.h.

Member Enumeration Documentation

EBits

enum EBits

Enum storing the bit informations for the packed information.

Enumerator
c_FractionBits	Number of bits to encode the fraction along the path.
c_ElectronBits	Number of bits to encode the number of electrons.
c_TotalBits	Total number of bits needed for the packed structure.
c_MaxFraction	Maximum integer value allowed for the fraction part.
c_MaxElectrons	Maximum number of electrons allowed.

Definition at line 35 of file VXDElectronDeposit.h.

               {
      c_FractionBits = 10,
      c_ElectronBits = 22,
      c_TotalBits = c_FractionBits + c_ElectronBits,
      c_MaxFraction = (1 << c_FractionBits) - 1,
      c_MaxElectrons = (1 << c_ElectronBits) - 1,
    };

Constructor & Destructor Documentation

VXDElectronDeposit() [1/2]

VXDElectronDeposit ( unsigned int  packed )

inlineexplicit

Create a new instance from a packed value.

Parameters

packed

value to be interpreted as packed fraction/electrons

Definition at line 50 of file VXDElectronDeposit.h.

: m_packed(packed) {}

VXDElectronDeposit() [2/2]

VXDElectronDeposit ( float  fraction, float  electrons  )

inline

create a new instance from a fraction along the path and a number of electrons.

Parameters

fraction	fraction along the path, should be 0<=x<=1
electrons	number of electrons deposited

Definition at line 57 of file VXDElectronDeposit.h.

    {
      const unsigned int intfrac = std::round(std::max(0.f, fraction) * static_cast<float>(c_MaxFraction));
      const unsigned int intelec = std::round(std::max(0.f, electrons));
      m_packed = std::min(intfrac, static_cast<unsigned int>(c_MaxFraction))
                 + (std::min(intelec, static_cast<unsigned int>(c_MaxElectrons)) << c_FractionBits);
    }

Member Function Documentation

getElectrons()

unsigned int getElectrons ( ) const

inline

get the number of deposited electrons

Definition at line 70 of file VXDElectronDeposit.h.

    {
      return (m_packed >> c_FractionBits) & c_MaxElectrons;
    }

getFraction()

float getFraction ( ) const

inline

get the fraction along the path

Definition at line 65 of file VXDElectronDeposit.h.

    {
      return (m_packed & c_MaxFraction) * 1.0 / static_cast<float>(c_MaxFraction);
    }

getPacked()

unsigned int getPacked ( ) const

inline

get the packed value

Definition at line 75 of file VXDElectronDeposit.h.

{ return m_packed; }

operator unsigned int()

operator unsigned int ( ) const

inline

convert to unsigned int using the packed representation

Definition at line 77 of file VXDElectronDeposit.h.

{ return m_packed; }

Member Data Documentation

m_packed

unsigned int m_packed

private

packed representation of the fraction and electron deposition

Definition at line 80 of file VXDElectronDeposit.h.

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The documentation for this class was generated from the following file:

• vxd/dataobjects/include/VXDElectronDeposit.h