PsfMatchTask¶
- class lsst.ip.diffim.PsfMatchTask(*args, **kwargs)¶
-
Base class for Psf Matching; should not be called directly
Notes
PsfMatchTask is a base class that implements the core functionality for matching the Psfs of two images using a spatially varying Psf-matching
lsst.afw.math.LinearCombinationKernel
. The Task requires the user to provide an instance of anlsst.afw.math.SpatialCellSet
, filled withlsst.ip.diffim.KernelCandidate
instances, and a list oflsst.afw.math.Kernels
of basis shapes that will be used for the decomposition. If requested, the Task also performs background matching and returns the differential background model as anlsst.afw.math.Kernel.SpatialFunction
.Invoking the Task
As a base class, this Task is not directly invoked. However,
run()
methods that are implemented on derived classes will make use of the core_solve()
functionality, which defines a sequence oflsst.afw.math.CandidateVisitor
classes that iterate through the KernelCandidates, first building up a per-candidate solution and then building up a spatial model from the ensemble of candidates. Sigma clipping is performed using the mean and standard deviation of all kernel sums (to reject variable objects), on the per-candidate substamp diffim residuals (to indicate a bad choice of kernel basis shapes for that particular object), and on the substamp diffim residuals using the spatial kernel fit (to indicate a bad choice of spatial kernel order, or poor constraints on the spatial model). The_diagnostic()
method logs information on the quality of the spatial fit, and also modifies the Task metadata.¶ Parameter
Description
spatialConditionNum
Condition number of the spatial kernel fit
spatialKernelSum
Kernel sum (10^{-0.4 *
Delta
; zeropoint}) of the spatial Psf-matching kernelALBasisNGauss
If using sum-of-Gaussian basis, the number of gaussians used
ALBasisDegGauss
If using sum-of-Gaussian basis, the deg of spatial variation of the Gaussians
ALBasisSigGauss
If using sum-of-Gaussian basis, the widths (sigma) of the Gaussians
ALKernelSize
If using sum-of-Gaussian basis, the kernel size
NFalsePositivesTotal
Total number of diaSources
NFalsePositivesRefAssociated
Number of diaSources that associate with the reference catalog
NFalsePositivesRefAssociated
Number of diaSources that associate with the source catalog
NFalsePositivesUnassociated
Number of diaSources that are orphans
metric_MEAN
Mean value of substamp diffim quality metrics across all KernelCandidates, for both the per-candidate (LOCAL) and SPATIAL residuals
metric_MEDIAN
Median value of substamp diffim quality metrics across all KernelCandidates, for both the per-candidate (LOCAL) and SPATIAL residuals
metric_STDEV
Standard deviation of substamp diffim quality metrics across all KernelCandidates, for both the per-candidate (LOCAL) and SPATIAL residuals
Debug variables
The
pipetask
command line interface supports a flag –debug to import @b debug.py from your PYTHONPATH. The relevant contents of debug.py for this Task include:import sys import lsstDebug def DebugInfo(name): di = lsstDebug.getInfo(name) if name == "lsst.ip.diffim.psfMatch": # enable debug output di.display = True # display mask transparency di.maskTransparency = 80 # show all the candidates and residuals di.displayCandidates = True # show kernel basis functions di.displayKernelBasis = False # show kernel realized across the image di.displayKernelMosaic = True # show coefficients of spatial model di.plotKernelSpatialModel = False # show fixed and spatial coefficients and coefficient histograms di.plotKernelCoefficients = True # show the bad candidates (red) along with good (green) di.showBadCandidates = True return di lsstDebug.Info = DebugInfo lsstDebug.frame = 1
Note that if you want additional logging info, you may add to your scripts:
import lsst.utils.logging as logUtils logUtils.trace_set_at("lsst.ip.diffim", 4)
Methods Summary
Empty (clear) the metadata for this Task and all sub-Tasks.
Get metadata for all tasks.
Get the task name as a hierarchical name including parent task names.
getName
()Get the name of the task.
Get a dictionary of all tasks as a shallow copy.
makeField
(doc)Make a
lsst.pex.config.ConfigurableField
for this task.makeSubtask
(name, **keyArgs)Create a subtask as a new instance as the
name
attribute of this task.timer
(name[, logLevel])Context manager to log performance data for an arbitrary block of code.
Methods Documentation
- getFullMetadata() TaskMetadata ¶
Get metadata for all tasks.
- Returns:
- metadata
TaskMetadata
The keys are the full task name. Values are metadata for the top-level task and all subtasks, sub-subtasks, etc.
- metadata
Notes
The returned metadata includes timing information (if
@timer.timeMethod
is used) and any metadata set by the task. The name of each item consists of the full task name with.
replaced by:
, followed by.
and the name of the item, e.g.:topLevelTaskName:subtaskName:subsubtaskName.itemName
using
:
in the full task name disambiguates the rare situation that a task has a subtask and a metadata item with the same name.
- getFullName() str ¶
Get the task name as a hierarchical name including parent task names.
- Returns:
- fullName
str
The full name consists of the name of the parent task and each subtask separated by periods. For example:
The full name of top-level task “top” is simply “top”.
The full name of subtask “sub” of top-level task “top” is “top.sub”.
The full name of subtask “sub2” of subtask “sub” of top-level task “top” is “top.sub.sub2”.
- fullName
- getName() str ¶
Get the name of the task.
- Returns:
- taskName
str
Name of the task.
- taskName
See also
getFullName
Get the full name of the task.
- getTaskDict() dict[str, weakref.ReferenceType[lsst.pipe.base.task.Task]] ¶
Get a dictionary of all tasks as a shallow copy.
- Returns:
- taskDict
dict
Dictionary containing full task name: task object for the top-level task and all subtasks, sub-subtasks, etc.
- taskDict
- classmethod makeField(doc: str) ConfigurableField ¶
Make a
lsst.pex.config.ConfigurableField
for this task.- Parameters:
- doc
str
Help text for the field.
- doc
- Returns:
- configurableField
lsst.pex.config.ConfigurableField
A
ConfigurableField
for this task.
- configurableField
Examples
Provides a convenient way to specify this task is a subtask of another task.
Here is an example of use:
class OtherTaskConfig(lsst.pex.config.Config): aSubtask = ATaskClass.makeField("brief description of task")
- makeSubtask(name: str, **keyArgs: Any) None ¶
Create a subtask as a new instance as the
name
attribute of this task.- Parameters:
- name
str
Brief name of the subtask.
- **keyArgs
Extra keyword arguments used to construct the task. The following arguments are automatically provided and cannot be overridden:
config
.parentTask
.
- name
Notes
The subtask must be defined by
Task.config.name
, an instance ofConfigurableField
orRegistryField
.