#include <AliFMDEncodedEdx.h>

Classes
struct	Spec

Public Types
enum	{ kNEBits = 8, kNLBits = 5, kEMask = 0xFF, kLMask = 0x1F }

Public Member Functions
	AliFMDEncodedEdx ()

virtual	~AliFMDEncodedEdx ()

Static Public Member Functions
static const Spec &	GetdEAxis ()

static const Spec &	GetdLAxis ()

static UInt_t	Encode (Double_t edep, Double_t length)

static void	Decode (UInt_t bits, Double_t &edep, Double_t &length)

static void	Decode (UInt_t bits, Double_t &edep, Double_t &length, Double_t &wEdep, Double_t &wLength)

static TH1 *	Make1D (const char name, const char title, UShort_t mode=true)

static TH2 *	Make2D (const char name, const char title, Bool_t xedep=true)

static Bool_t	IsAvailable (UInt_t alirootRev)

Static Private Member Functions
static UInt_t	EncodeOne (Double_t v, const Spec &a)

static Double_t	DecodeOne (UInt_t b, const Spec &a)

static Double_t	DecodeOne (UInt_t b, Double_t &w, const Spec &a)

Detailed Description

Class to encode the energy loss \(d\Delta\) and path length \(dx\) of a particle into track reference bits. A total of 13 bits are available. Of these 8 are used for \(d\Delta\) and 5 for \(dx\).

The encoding is done by binning. That is, for a given value of \(d\Delta\) or \(dx\) we calculate a bin number and store that. The reverse decoding is done by looking up the bin center of the bin number stored. Note, that the bin numbers go from 0 to 255 (for \(d\Delta\)) and 31 (for \(dx\)).

The bins become progressively wider. That is, we define 3 regions.

Lower region which spans the lower 10% of the distribution has 75% of all avaible bins.
Middle region which spans from the 10% to 20% of the distribtion and has 20% of the available bins.
Upper region which covers the rest of the distribtion in 5% of the available bins

Type	N bins	Range	bin	value	bin	value
\(d\Delta\)	256	0-11	192	1.1	243	2.2
\(dx\)	32	0-0.7	24	0.07	30	1.4

Currently there's no support of other schemas

Definition at line 52 of file AliFMDEncodedEdx.h.

Member Enumeration Documentation

anonymous enum

How the 13 bits are distributed

Enumerator
kNEBits
kNLBits
kEMask
kLMask

Definition at line 200 of file AliFMDEncodedEdx.h.

Constructor & Destructor Documentation

AliFMDEncodedEdx::AliFMDEncodedEdx ( )

inline

Constructor - a no-op

Definition at line 209 of file AliFMDEncodedEdx.h.

virtual AliFMDEncodedEdx::~AliFMDEncodedEdx ( )

inlinevirtual

Destructor - a no-op

Definition at line 213 of file AliFMDEncodedEdx.h.

Member Function Documentation

static void AliFMDEncodedEdx::Decode	(	UInt_t	bits,
		Double_t &	edep,
		Double_t &	length
	)

inlinestatic

Decode the lower 13-bit of the input into \(d\Delta\) and \(dx\)

Parameters

bits	Encoded 13-bit word (lower 13 bit)
edep	On return, the \(d\Delta\)
length	On return, the \(dx\)

Definition at line 259 of file AliFMDEncodedEdx.h.

Referenced by AliFMDMCTrackDensity::ProcessRef(), and AliFMDMCTrackELoss::ProcessRef().

static void AliFMDEncodedEdx::Decode	(	UInt_t	bits,
		Double_t &	edep,
		Double_t &	length,
		Double_t &	wEdep,
		Double_t &	wLength
	)

inlinestatic

Decode the lower 13-bit of the input into \(d\Delta\) and \(dx\)

Parameters

bits	Encoded 13-bit word (lower 13 bit)
edep	On return, the \(d\Delta\)
length	On return, the \(dx\)
wEdep	On return, the width of the corresponding \(d\Delta\) bin
wLength	On return, the width of the corresponding \(dx\) bin

Definition at line 273 of file AliFMDEncodedEdx.h.

static Double_t AliFMDEncodedEdx::DecodeOne	(	UInt_t	b,
		const Spec &	a
	)

inlinestaticprivate

Decode a value

Parameters

b	Encoded value
a	Bin specification

Returns: Decoded value

Definition at line 375 of file AliFMDEncodedEdx.h.

Referenced by Decode().

static Double_t AliFMDEncodedEdx::DecodeOne	(	UInt_t	b,
		Double_t &	w,
		const Spec &	a
	)

inlinestaticprivate

Decode a value

Parameters

b	Encoded value
a	Bin specification
w	On return, the bin width

Returns: Decoded value

Definition at line 389 of file AliFMDEncodedEdx.h.

static UInt_t AliFMDEncodedEdx::Encode	(	Double_t	edep,
		Double_t	length
	)

inlinestatic

Encode \(d\Delta\) and \(dx\) into a 13bit number.

Parameters

edep	\(d\Delta\)
length	\(dx\)

Returns: 13-bit (lower) encoded value

Definition at line 246 of file AliFMDEncodedEdx.h.

static UInt_t AliFMDEncodedEdx::EncodeOne	(	Double_t	v,
		const Spec &	a
	)

inlinestaticprivate

Encode one value

Parameters

v	Value
a	Bin specification

Returns: Encoded value

Definition at line 361 of file AliFMDEncodedEdx.h.

Referenced by Encode().

static const Spec& AliFMDEncodedEdx::GetdEAxis ( )

inlinestatic

Get the \(d\Delta\) bin specification. If not initialized already, do so .

Returns: Constant reference to \(d\Delta\) bin specification

Definition at line 220 of file AliFMDEncodedEdx.h.

Referenced by AliFMDMCTrackELoss::CreateOutputObjects(), Decode(), Encode(), Make1D(), Make2D(), AliFMDMCTrackInspector::RingHistos::MakeIncreasingAxis(), and AliFMDMCHitEnergyFitter::RingHistos::MakeIncreasingAxis().

static const Spec& AliFMDEncodedEdx::GetdLAxis ( )

inlinestatic

Get the \(dx\) bin specification. If not initialized already, do so .

Returns: Constant reference to \(dx\) bin specification

Definition at line 232 of file AliFMDEncodedEdx.h.

Referenced by Decode(), Encode(), Make1D(), and Make2D().

static Bool_t AliFMDEncodedEdx::IsAvailable ( UInt_t alirootRev )

inlinestatic

Check if the encoded \(d\Delta\) and \(dx\) are available in the upper 13 bits of the unique ID field of track references.

Parameters

alirootRev AliROOT revision of the code that produced the track references. Note, it cannot be the revision of AliROOT running, since that can be much newer (or older) than the code that made the track references. One should get this information from the object stored in the ESD tree's user objects.

Returns: true if alirootRev is larger than some fixed number set when this class was committed to SVN.

Definition at line 347 of file AliFMDEncodedEdx.h.

static TH1* AliFMDEncodedEdx::Make1D	(	const char *	name,
		const char *	title,
		UShort_t	mode = `true`
	)

inlinestatic

Make a 1-dimension histogram with the natural binning for the encoding for either \(d\Delta\) or \(dx\)

Parameters

name	Name of produced histogram
title	Title of produced histogram
mode	If 0, make histogram for \(d\Delta\). If 1 for \(dx\), if 2 for \(d\Delta/dx\)

Returns: Newly allocated histogram

Definition at line 290 of file AliFMDEncodedEdx.h.

static TH2* AliFMDEncodedEdx::Make2D	(	const char *	name,
		const char *	title,
		Bool_t	xedep = `true`
	)

inlinestatic

Make a 2-dimension histogram with the natural binning for the encoding of \(d\Delta\) versus \(dx\) (or vice versa)

Parameters

name	Name of produced histogram
title	Title of produced histogram
xedep	If true, put \(d\Delta\) on the X-axis, otherwise for \(dx\)

Returns: Newly allocated histogram

Definition at line 321 of file AliFMDEncodedEdx.h.

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

PWGLF/FORWARD/analysis2/AliFMDEncodedEdx.h

Classes

Public Types

Public Member Functions

Static Public Member Functions

Static Private Member Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation