org.lcsim.recon.tracking.digitization.sisim

Class NearestNeighborRMS

java.lang.Object

org.lcsim.recon.tracking.digitization.sisim.NearestNeighborRMS

All Implemented Interfaces:

ClusteringAlgorithm

public class NearestNeighborRMS
extends Object
implements ClusteringAlgorithm

This class uses a nearest neighbor algorithm to find clusters of hits on a set of silicon sensor electrodes (i.e., an instance of SiStrips or SiPixels). The algorithm first finds possible cluster seeds that are above the seed threshold. Starting from a seed, the neighbor strips/pixels are searched to see if we have hits above the neighbor threshold. Neighbor channels are added until we have a cluster where every neighboring channel for the cluster has charge lying below the neighbor threshold. Thresholds are specified in units of RMS noise of each electrode. HashMaps are used to speed up the algorithm when there are large numbers of hits, and the algorithm is expected to scale linearly with the number of RawTrackerHits on the electrodes.

Author:

Tim Nelson (adapted from NearestNeighbor code of Rich Partridge)

Field Summary

Fields

Modifier and Type	Field and Description
private double	_cluster_threshold
private static String	_NAME
private double	_neighbor_threshold
private double	_seed_threshold

Constructor Summary

Constructors

Constructor and Description
NearestNeighborRMS() Instantiate NearestNeighborRMS with default thresholds: seed_threshold = 4*RMS noise neighbor_threhold = 3*RMS noise cluster_threshold = 4*RMS noise
NearestNeighborRMS(double seed_threshold, double neighbor_threshold, double cluster_threshold) Instantiate NearestNeighborRMS with specified thresholds.

Method Summary

Methods

Modifier and Type	Method and Description
List<List<RawTrackerHit>>	findClusters(SiSensorElectrodes electrodes, ReadoutChip readout_chip, List<RawTrackerHit> raw_hits) Find clusters using the nearest neighbor algorithm.
double	getClusterThreshold() Return the cluster threshold.
String	getName() Return the name of the clustering algorithm.
double	getNeighborThreshold() Return the neighbor threshold.
double	getSeedThreshold() Return the seed threshold.
void	setClusterThreshold(double cluster_threshold) Set the cluster threshold.
void	setNeighborThreshold(double neighbor_threshold) Set the neighbor threshold.
void	setSeedThreshold(double seed_threshold) Set the seed threshold.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

_NAME

private static String _NAME

_seed_threshold

private double _seed_threshold

_neighbor_threshold

private double _neighbor_threshold

_cluster_threshold

private double _cluster_threshold

Constructor Detail

NearestNeighborRMS

public NearestNeighborRMS(double seed_threshold,
                  double neighbor_threshold,
                  double cluster_threshold)

Instantiate NearestNeighborRMS with specified thresholds. Seed threshold is the minimum charge to initiate a cluster. Neighbor threshold is the minimum charge to add a neighboring cell to a cluster. Cluster threshold is minimum charge of the entire cluster. All thresholds are in units of RMS noise of the channel(s).

Parameters:

seed_threshold - seed threhold

neighbor_threshold - neighbor threshold

cluster_threshold - cluster threshold

NearestNeighborRMS

public NearestNeighborRMS()

Instantiate NearestNeighborRMS with default thresholds: seed_threshold = 4*RMS noise neighbor_threhold = 3*RMS noise cluster_threshold = 4*RMS noise

Method Detail

setSeedThreshold

public void setSeedThreshold(double seed_threshold)

Set the seed threshold. Units are RMS noise.

Parameters:

seed_threshold - seed threshold

setNeighborThreshold

public void setNeighborThreshold(double neighbor_threshold)

Set the neighbor threshold. Units are RMS noise.

Parameters:

neighbor_threshold - neighbor threshold

setClusterThreshold

public void setClusterThreshold(double cluster_threshold)

Set the cluster threshold. Units are RMS noise.

Parameters:

cluster_threshold - cluster threshold

getSeedThreshold

public double getSeedThreshold()

Return the seed threshold. Units are RMS noise.

Returns:

seed threshold

getNeighborThreshold

public double getNeighborThreshold()

Return the neighbor threshold. Units are RMS noise.

Returns:

neighbor threshold

getClusterThreshold

public double getClusterThreshold()

Return the cluster threshold. Units are RMS noise.

Returns:

cluster threshold

getName

public String getName()

Return the name of the clustering algorithm.

Returns:

_name clusting algorithm name

findClusters

public List<List<RawTrackerHit>> findClusters(SiSensorElectrodes electrodes,
                                     ReadoutChip readout_chip,
                                     List<RawTrackerHit> raw_hits)

Find clusters using the nearest neighbor algorithm.

Specified by:

findClusters in interface ClusteringAlgorithm

Parameters:

electrodes - electrodes we are clustering

readout_chip - readout chip for these electrodes

raw_hits - List of RawTrackerHits to be clustered

Returns:

list of clusters, with a cluster being a list of RawTrackerHits