lsst.meas.algorithms.objectSizeStarSelector Namespace Reference

Classes
class	EventHandler
class	ObjectSizeNoGoodSourcesError
class	ObjectSizeNoSourcesError
class	ObjectSizeStarSelectorConfig
class	ObjectSizeStarSelectorTask

Functions
	_assignClusters (yvec, centers)
	_kcenters (yvec, nCluster, useMedian=False, widthStdAllowed=0.15)
	_improveCluster (yvec, centers, clusterId, nsigma=2.0, nIteration=10, clusterNum=0, widthStdAllowed=0.15)
	plot (mag, width, centers, clusterId, marker="o", markersize=2, markeredgewidth=0, ltype='-', magType="model", clear=True)

Variables
	_LOG = getLogger(__name__)

Function Documentation

_assignClusters()

lsst.meas.algorithms.objectSizeStarSelector._assignClusters ( yvec, centers )

protected

Return a vector of centerIds based on their distance to the centers.

Definition at line 197 of file objectSizeStarSelector.py.

_improveCluster()

lsst.meas.algorithms.objectSizeStarSelector._improveCluster ( yvec, centers, clusterId, nsigma = 2.0, nIteration = 10, clusterNum = 0, widthStdAllowed = 0.15 )

protected

Improve our estimate of one of the clusters (clusterNum) by sigma-clipping around its median.

Definition at line 270 of file objectSizeStarSelector.py.

_kcenters()

lsst.meas.algorithms.objectSizeStarSelector._kcenters ( yvec, nCluster, useMedian = False, widthStdAllowed = 0.15 )

protected

A classic k-means algorithm, clustering yvec into nCluster clusters

Return the set of centres, and the cluster ID for each of the points

If useMedian is true, use the median of the cluster as its centre, rather than
the traditional mean

Serge Monkewitz points out that there other (maybe smarter) ways of seeding the means:
   "e.g. why not use the Forgy or random partition initialization methods"
however, the approach adopted here seems to work well for the particular sorts of things
we're clustering in this application

Definition at line 228 of file objectSizeStarSelector.py.

plot()

lsst.meas.algorithms.objectSizeStarSelector.plot	(		mag,
			width,
			centers,
			clusterId,
			marker = "o",
			markersize = 2,
			markeredgewidth = 0,
			ltype = '-',
			magType = "model",
			clear = True )

Definition at line 306 of file objectSizeStarSelector.py.

Variable Documentation

_LOG

lsst.meas.algorithms.objectSizeStarSelector._LOG = getLogger(__name__)

protected

Definition at line 42 of file objectSizeStarSelector.py.