Algorithm for cluster finding in a linear array of channels. More...

#include <CbmStsAlgoFindClusters.h>

Collaboration diagram for CbmStsAlgoFindClusters:

Public Types
typedef std::pair< const CbmStsDigi *, Long64_t >	InputData
	Typedef for input data.

Public Member Functions
	CbmStsAlgoFindClusters ()
	Default constructor.

virtual	~CbmStsAlgoFindClusters ()
	Destructor.

Long64_t	Exec (const std::vector< InputData > &input, std::vector< CbmStsCluster > &output, UInt_t address, UShort_t nChannels, UShort_t channelOffset, Double_t timeCutSigma, Double_t timeCutAbs, Bool_t connectEdge, const CbmStsParModule *modPar)
	Algorithm execution.

Private Member Functions
Short_t	ChanLeft (UShort_t channel)
	Number of left neighbour channel.

Short_t	ChanRight (UShort_t channel)
	Number of right neighbour channel.

Bool_t	CheckChannel (Short_t channel, Double_t time)
	Check for a matching digi in a given channel.

void	CreateCluster (UShort_t channel)
	Create a cluster from an active channel.

Bool_t	IsActive (Short_t channel)
	Check for a channel being active.

Bool_t	ProcessDigi (UShort_t channel, Double_t time, Int_t index)
	Process one input digi.

Private Attributes
std::vector< std::pair< Long64_t, Double_t > >	fStatus {1024, {-1, 0.}}
	Status buffer.

std::vector< CbmStsCluster > *	fOutput = nullptr
	Pointer to output vector.

UInt_t	fAddress = 0
	Unique module address for clusters.

UShort_t	fNofChannels = 0
	Number of channels.

UShort_t	fChannelOffset = 0
	Number of first channel.

Double_t	fTimeCutSig = 0.
	Time cut in multiples of error.

Double_t	fTimeCutAbs = 0.
	Absolute time cut [ns].

Bool_t	fConnectEdge = kFALSE
	Connect last and first channel.

const CbmStsParModule *	fModPar = nullptr

Detailed Description

Algorithm for cluster finding in a linear array of channels.

Author: Volker Friese v.fri.nosp@m.ese@.nosp@m.gsi.d.nosp@m.e

Since: 05.04.2017

Date: 22.03.2020

Cluster finding is performed in a linear array of channels, corresponding e.g. to one side of a STS sensor / module. A cluster is defined by a group of matching digis. Two digis are considered matching if they are in neighbouring channels and their time difference is less than the chosen limit.

Clustering is performed in a streaming way, i.e. on adding of each digi by the method ProcessDigi. If a cluster in the same or in a neighbour channel is found which does not match the digi, it is written to the output. This makes the runtime of the algorithm independent of input data size, but has as a consequence that the output clusters are not sorted w.r.t. time.

The time resolution is assumed to be the same for all digis and has to be specified to the Exec method. The time cut can be specified in units of the time resolution or in absolute units. The latter, if positive, overrides the former.

Clustering around-the-edge means periodic boundary conditions, i.e., the first and the last channel are considered neighbours.

The digis are connected to the cluster in the order left to right, i.e. with ascending channel number. In case of clustering round the edge, the channel at the right edge is considered left neighbour of the first channel, i.e. the cluster starts with high channel number.

The algorithm is described in: V. Friese, EPJ Web of Conferences 214 (2019) 01008

Definition at line 59 of file CbmStsAlgoFindClusters.h.

Member Typedef Documentation

◆ InputData

std::pair<const CbmStsDigi*, Long64_t> CbmStsAlgoFindClusters::InputData

Typedef for input data.

Definition at line 63 of file CbmStsAlgoFindClusters.h.

Constructor & Destructor Documentation

◆ CbmStsAlgoFindClusters()

CbmStsAlgoFindClusters::CbmStsAlgoFindClusters ( )

inline

Default constructor.

Definition at line 67 of file CbmStsAlgoFindClusters.h.

◆ ~CbmStsAlgoFindClusters()

virtual CbmStsAlgoFindClusters::~CbmStsAlgoFindClusters ( )

inlinevirtual

Destructor.

Definition at line 71 of file CbmStsAlgoFindClusters.h.

Member Function Documentation

◆ ChanLeft()

Short_t CbmStsAlgoFindClusters::ChanLeft ( UShort_t channel )

inlineprivate

Number of left neighbour channel.

Parameters

channel Channel number

Returns: Number of left neighbour

In case of clustering round-the-edge, the left neighbour of the first channel is the last channel. Otherwise, it is -1.

Definition at line 103 of file CbmStsAlgoFindClusters.h.

References fConnectEdge, and fNofChannels.

Referenced by CreateCluster(), and ProcessDigi().

◆ ChanRight()

Short_t CbmStsAlgoFindClusters::ChanRight ( UShort_t channel )

inlineprivate

Number of right neighbour channel.

Parameters

channel Channel number

Returns: Number of right neighbour

In case of clustering round-the-edge, the right neighbour of the last channel is the first channel. Otherwise, it is the increment.

Definition at line 117 of file CbmStsAlgoFindClusters.h.

References fConnectEdge, and fNofChannels.

Referenced by CreateCluster(), and ProcessDigi().

◆ CheckChannel()

Bool_t CbmStsAlgoFindClusters::CheckChannel	(	Short_t	channel,
		Double_t	time )

private

Check for a matching digi in a given channel.

Parameters

channel	Channel number
time	Time [ns]

Returns: kTRUE if matching digi found

The digi is considered matching if the time difference between the time argument and the time of the active digi in the channel is within the time window defined by the cut value.

Definition at line 27 of file CbmStsAlgoFindClusters.cxx.

References CreateCluster(), fModPar, fNofChannels, fStatus, fTimeCutAbs, fTimeCutSig, CbmStsParModule::GetParAsic(), CbmStsParAsic::GetTimeResol(), and IsActive().

Referenced by ProcessDigi().

◆ CreateCluster()

void CbmStsAlgoFindClusters::CreateCluster ( UShort_t channel )

private

Create a cluster from an active channel.

Parameters

channel Channel number

Starting from the specified channel, a cluster is created by searching for active neighbours left and right until an inactive channel is found.

No action if the channel is not active.

Definition at line 100 of file CbmStsAlgoFindClusters.cxx.

References ChanLeft(), ChanRight(), fAddress, fConnectEdge, first, fNofChannels, fOutput, fStatus, IsActive(), and CbmCluster::SetAddress().

Referenced by CheckChannel(), and Exec().

◆ Exec()

Long64_t CbmStsAlgoFindClusters::Exec	(	const std::vector< InputData > &	input,
		std::vector< CbmStsCluster > &	output,
		UInt_t	address,
		UShort_t	nChannels,
		UShort_t	channelOffset,
		Double_t	timeCutSigma,
		Double_t	timeCutAbs,
		Bool_t	connectEdge,
		const CbmStsParModule *	modPar )

Algorithm execution.

Parameters

input	Vector of input data (pairs of digi and index)
output	Vector of output clusters
address	Cluster address (module)
nChannels	Number of channels
channelOffset	Number of first channel
timeResol	Time resolution of digis [ns]
timeCutSigma	Time cut in units of time resolution
timeCutAbs	Time cut in ns
connectEdge	If true, clustering round-the-edge is done.
isBackSide	Treat back-side clusters w.r.t. channel number

The channel numbers are assumed to be consecutive, starting with channelOffset. If connectEdge is specififed, the first channel and the last channel are considered neighbours.

Definition at line 59 of file CbmStsAlgoFindClusters.cxx.

References CreateCluster(), fAddress, fChannelOffset, fConnectEdge, fModPar, fNofChannels, fOutput, fStatus, fTimeCutAbs, fTimeCutSig, and ProcessDigi().

Referenced by CbmStsRecoModule::FindClusters().

◆ IsActive()

Bool_t CbmStsAlgoFindClusters::IsActive ( Short_t channel )

inlineprivate

Check for a channel being active.

Parameters

channel Channel number

Returns: kTRUE is the channel is active; else kFALSE

Definition at line 152 of file CbmStsAlgoFindClusters.h.

References fNofChannels, and fStatus.

Referenced by CheckChannel(), and CreateCluster().

◆ ProcessDigi()

Bool_t CbmStsAlgoFindClusters::ProcessDigi	(	UShort_t	channel,
		Double_t	time,
		Int_t	index )

private

Process one input digi.

Parameters

channel	Channel number
time	Digi time [ns]
index	Index of digi object in its TClonesArray

Returns: kTRUE is digi was successfully processed

Depending on the state of the respective channel, the proper action is taken.

Definition at line 141 of file CbmStsAlgoFindClusters.cxx.

References ChanLeft(), ChanRight(), CheckChannel(), fNofChannels, and fStatus.

Referenced by Exec().

Member Data Documentation

◆ fAddress

UInt_t CbmStsAlgoFindClusters::fAddress = 0

private

Unique module address for clusters.

Definition at line 183 of file CbmStsAlgoFindClusters.h.

Referenced by CreateCluster(), and Exec().

◆ fChannelOffset

UShort_t CbmStsAlgoFindClusters::fChannelOffset = 0

private

Number of first channel.

Definition at line 185 of file CbmStsAlgoFindClusters.h.

Referenced by Exec().

◆ fConnectEdge

Bool_t CbmStsAlgoFindClusters::fConnectEdge = kFALSE

private

Connect last and first channel.

Definition at line 188 of file CbmStsAlgoFindClusters.h.

Referenced by ChanLeft(), ChanRight(), CreateCluster(), and Exec().

◆ fModPar

const CbmStsParModule* CbmStsAlgoFindClusters::fModPar = nullptr

private

Definition at line 189 of file CbmStsAlgoFindClusters.h.

Referenced by CheckChannel(), and Exec().

◆ fNofChannels

UShort_t CbmStsAlgoFindClusters::fNofChannels = 0

private

Number of channels.

Definition at line 184 of file CbmStsAlgoFindClusters.h.

Referenced by ChanLeft(), ChanRight(), CheckChannel(), CreateCluster(), Exec(), IsActive(), and ProcessDigi().

◆ fOutput

std::vector<CbmStsCluster>* CbmStsAlgoFindClusters::fOutput = nullptr

private

Pointer to output vector.

Definition at line 180 of file CbmStsAlgoFindClusters.h.

Referenced by CreateCluster(), and Exec().

◆ fStatus

std::vector<std::pair<Long64_t, Double_t> > CbmStsAlgoFindClusters::fStatus {1024, {-1, 0.}}

private

Status buffer.

The vector index is the channel number. The first element of the content is the digi index, the second one the time.

Definition at line 177 of file CbmStsAlgoFindClusters.h.

Referenced by CheckChannel(), CreateCluster(), Exec(), IsActive(), and ProcessDigi().

◆ fTimeCutAbs

Double_t CbmStsAlgoFindClusters::fTimeCutAbs = 0.

private

Absolute time cut [ns].

Definition at line 187 of file CbmStsAlgoFindClusters.h.

Referenced by CheckChannel(), and Exec().

◆ fTimeCutSig

Double_t CbmStsAlgoFindClusters::fTimeCutSig = 0.

private

Time cut in multiples of error.

Definition at line 186 of file CbmStsAlgoFindClusters.h.

Referenced by CheckChannel(), and Exec().

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

Public Types

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

◆ InputData

Constructor & Destructor Documentation

◆ CbmStsAlgoFindClusters()

◆ ~CbmStsAlgoFindClusters()

Member Function Documentation

◆ ChanLeft()

◆ ChanRight()

◆ CheckChannel()

◆ CreateCluster()

◆ Exec()

◆ IsActive()

◆ ProcessDigi()

Member Data Documentation

◆ fAddress

◆ fChannelOffset

◆ fConnectEdge

◆ fModPar

◆ fNofChannels

◆ fOutput

◆ fStatus

◆ fTimeCutAbs

◆ fTimeCutSig