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DgsReduction v1

Summary

Top-level workflow algorithm for DGS reduction.

Properties

Name	Direction	Type	Default	Description
SampleInputFile	Input	string		File containing the sample data to reduce. Allowed extensions: [‘_event.nxs’]
SampleInputWorkspace	Input	MatrixWorkspace		Workspace to be reduced
SampleInputMonitorWorkspace	Input	MatrixWorkspace		A monitor workspace associated with the input sample workspace.
DetCalFilename	Input	string		A detector calibration file.
RelocateDetectors	Input	boolean	False	Move detectors to position specified in cal file.
IncidentEnergyGuess	Input	number	Optional	Set the value of the incident energy guess in meV.
UseIncidentEnergyGuess	Input	boolean	False	Use the incident energy guess as the actual value (will not be calculated).
TimeZeroGuess	Input	number	Optional	Set the value of time zero offset in microseconds.
Monitor1SpecId	Input	number	Optional	Spectrum No for the first monitor to use in Ei calculation.
Monitor2SpecId	Input	number	Optional	Spectrum No for the second monitor to use in Ei calculation.
EnergyTransferRange	Input	dbl list		A comma separated list of first bin boundary, width, last bin boundary. Negative width value indicates logarithmic binning.
SofPhiEIsDistribution	Input	boolean	True	The final S(Phi, E) data is made to be a distribution.
HardMaskFile	Input	string		A file or workspace containing a hard mask. Allowed extensions: [‘.xml’]
GroupingFile	Input	string		A file containing grouping (mapping) information. Allowed extensions: [‘.xml’]
ShowIntermediateWorkspaces	Input	boolean	False	Flag to show the intermediate workspaces (diagnostic mask, integrated detector vanadium, integrated absolute units) from the reduction.
IncidentBeamNormalisation	Input	string	None	Options for incident beam normalisation on data. Allowed values: [‘None’, ‘ByCurrent’, ‘ToMonitor’]
MonitorIntRangeLow	Input	number	Optional	Set the lower bound for monitor integration.
MonitorIntRangeHigh	Input	number	Optional	Set the upper bound for monitor integration.
TimeIndepBackgroundSub	Input	boolean	False	If true, time-independent background will be calculated and removed.
TibTofRangeStart	Input	number	Optional	Set the lower TOF bound for time-independent background subtraction.
TibTofRangeEnd	Input	number	Optional	Set the upper TOF bound for time-independent background subtraction.
CorrectKiKf	Input	boolean	True	Apply the ki/kf correction.
DetectorVanadiumInputFile	Input	string		File containing the sample detector vanadium data to reduce. Allowed extensions: [‘_event.nxs’]
DetectorVanadiumInputWorkspace	Input	MatrixWorkspace		Sample detector vanadium workspace to be reduced
DetectorVanadiumInputMonitorWorkspace	Input	MatrixWorkspace		A monitor workspace associated with the input sample detector vanadium workspace.
SaveProcessedDetVan	Input	boolean	False	Save the processed detector vanadium workspace
SaveProcDetVanFilename	Input	string		Provide a filename for saving the processed detector vanadium. Allowed extensions: [‘.nxs’]
UseProcessedDetVan	Input	boolean	False	If true, treat the detector vanadium as processed. This includes not running diagnostics on the processed data.
UseBoundsForDetVan	Input	boolean	False	If true, integrate the detector vanadium over a given range.
DetVanIntRangeLow	Input	number	Optional	Set the lower bound for integrating the detector vanadium.
DetVanIntRangeHigh	Input	number	Optional	Set the upper bound for integrating the detector vanadium.
DetVanIntRangeUnits	Input	string	Energy	Options for the units on the detector vanadium integration. Allowed values: [‘Energy’, ‘Wavelength’, ‘TOF’]
HighCounts	Input	number	Optional	Mask detectors above this threshold.
LowCounts	Input	number	Optional	Mask detectors below this threshold.
LowOutlier	Input	number	Optional	Lower bound defining outliers as fraction of median value
HighOutlier	Input	number	Optional	Upper bound defining outliers as fraction of median value
MedianTestHigh	Input	number	Optional	Mask detectors above this threshold.
MedianTestLow	Input	number	Optional	Mask detectors below this threshold.
MedianTestLevelsUp	Input	number	0	Mask detectors below this threshold.
MedianTestCorrectForSolidAngle	Input	boolean	False	Flag to correct for solid angle efficiency.
ErrorBarCriterion	Input	number	Optional	Some selection criteria for the detector tests.
DetectorVanadium2InputFile	Input	string		File containing detector vanadium data to compare against. Allowed extensions: [‘_event.nxs’]
DetectorVanadium2InputWorkspace	Input	MatrixWorkspace		Detector vanadium workspace to compare against
DetectorVanadium2InputMonitorWorkspace	Input	MatrixWorkspace		A monitor workspace associated with the input comparison detector vanadium workspace.
DetVanRatioVariation	Input	number	Optional	Mask detectors if the time variation is above this threshold.
BackgroundCheck	Input	boolean	False	If true, run a background check on detector vanadium.
SamBkgMedianTestHigh	Input	number	Optional	Mask detectors above this threshold.
SamBkgMedianTestLow	Input	number	Optional	Mask detectors below this threshold.
SamBkgErrorBarCriterion	Input	number	Optional	Some selection criteria for the detector tests.
BackgroundTofStart	Input	number	Optional	Start TOF for the background check.
BackgroundTofEnd	Input	number	Optional	End TOF for the background check.
RejectZeroBackground	Input	boolean	False	If true, check the background region for anomolies.
PsdBleed	Input	boolean	False	If true, perform a PSD bleed test.
MaxFramerate	Input	number	Optional	The maximum framerate to check.
IgnoredPixels	Input	number	Optional	A list of pixels to ignore in the calculations.
DoAbsoluteUnits	Input	boolean	False	If true, perform an absolute units normalisation.
AbsUnitsSampleInputFile	Input	string		The sample (vanadium) file used in the absolute units normalisation.
AbsUnitsSampleInputWorkspace	Input	MatrixWorkspace		The sample (vanadium) workspace for absolute units normalisation.
AbsUnitsSampleInputMonitorWorkspace	Input	MatrixWorkspace		A monitor workspace associated with the input absolute units sample workspace.
AbsUnitsGroupingFile	Input	string		Grouping file for absolute units normalisation.
AbsUnitsDetectorVanadiumInputFile	Input	string		The detector vanadium file used in the absolute units normalisation.
AbsUnitsDetectorVanadiumInputWorkspace	Input	MatrixWorkspace		The detector vanadium workspace for absolute units normalisation.
AbsUnitsDetectorVanadiumInputMonitorWorkspace	Input	MatrixWorkspace		A monitor workspace associated with the input absolute units sample detector vanadium workspace.
AbsUnitsIncidentEnergy	Input	number	Optional	The incident energy for the vanadium sample.
AbsUnitsMinimumEnergy	Input	number	Optional	The minimum energy for the integration range.
AbsUnitsMaximumEnergy	Input	number	Optional	The maximum energy for the integration range.
VanadiumMass	Input	number	Optional	The mass of vanadium.
SampleMass	Input	number	1	The mass of sample.
SampleRmm	Input	number	1	The rmm of sample.
AbsUnitsLowOutlier	Input	number	Optional	Lower bound defining outliers as fraction of median value
AbsUnitsHighOutlier	Input	number	Optional	Upper bound defining outliers as fraction of median value
AbsUnitsMedianTestHigh	Input	number	Optional	Mask detectors above this threshold.
AbsUnitsMedianTestLow	Input	number	Optional	Mask detectors below this threshold.
AbsUnitsErrorBarCriterion	Input	number	Optional	Some selection criteria for the detector tests.
DoPowderDataConversion	Input	boolean	False	Flag to switch on converting DeltaE to SQW.
PowderMomTransferRange	Input	dbl list		A comma separated list of first bin boundary, width, last bin boundary. Negative width value indicates logarithmic binning.
SavePowderNexusFile	Input	boolean	True	Flag to use to save a processed NeXus file for powder data.
SavePowderNexusFilename	Input	string		Provide a filename for saving the processed powder data. Allowed extensions: [‘.nxs’]
OutputWorkspace	Output	MatrixWorkspace	Mandatory	Provide a name for the output workspace.
ReductionProperties	Output	string

Description

This is the top-level workflow algorithm for direct geometry spectrometer data reduction. This algorithm is responsible for gathering the necessary parameters and generating calls to other workflow or standard algorithms.

Workflow

Parameters for the child algorithms are not shown due to the sheer number. They will be detailed in the child algorithm diagrams. Items in parallelograms are output workspaces from their respective algorithms. Not all output workspaces are subsequently used by other algorithms.

Usage

Example - Simplest SNS Script

config['default.facility'] = "SNS"
# SNS reduction does not require IncidentEnergyGuess since the NeXus
# files contain an EnergyRequest log.
ws = DgsReduction(SampleInputFile="CNCS_7860_event.nxs")
# More than one output from DgsReduction
# (E vs Phi Workspace, Name of Property Manager)
w = ws[0]
# Check the conversion
xaxis = w.getAxis(0).getUnit()
print("X axis = {} / {}".format(xaxis.caption(), xaxis.symbol()))
print("Energy mode = {}".format(w.getEMode()))
print("Workspace type = {}".format(w.id()))

Output:

X axis = Energy transfer / meV
Energy mode = Direct
Workspace type = Workspace2D

Example - Simplest ISIS Script

config['default.facility'] = "ISIS"
# ISIS reduction required IncidentEnergyGuess since RAW files don't
# have a corresponding log.
ws = DgsReduction(SampleInputFile="MAR11001.raw",
                  IncidentEnergyGuess=12)
# More than one output from DgsRedution
# (E vs Phi Workspace, Name of Property Manager)
w = ws[0]
# Check the conversion
xaxis = w.getAxis(0).getUnit()
print("X axis = {} / {}".format(xaxis.caption(), xaxis.symbol()))
print("Energy mode = {}".format(w.getEMode()))
print("Workspace type = {}".format(w.id()))

Output:

X axis = Energy transfer / meV
Energy mode = Direct
Workspace type = Workspace2D

Example - Get as Eventworkspace for SNS

The following shows that event data can be the result of the redcuction instead of histogram data.

config['default.facility'] = "SNS"
ws = DgsReduction(SampleInputFile="CNCS_7860_event.nxs",
                  IncidentBeamNormalisation="ByCurrent",
                  SofPhiEIsDistribution=False)
w = ws[0]
print("Workspace type = {}".format(w.id()))
print("Number of events = {}".format(w.getNumberEvents()))

Output:

Workspace type = EventWorkspace
Number of events = 78037

Example - Correct Data Before Reduction for SNS

The following is a contrived example to show that the data can be loaded and corrected and/or filtered before passing it to the algorithm. The key here is that the *InputWorkspace properties must be used. It also shows a couple of more properties being used.

config['default.facility'] = "SNS"
ws = Load("CNCS_7860_event.nxs", LoadMonitors=True)
monitor = ws[1]
valC3 = ws[0].getRun()['Phase3'].getStatistics().median
ws = FilterByLogValue(ws[0], LogName="Phase3", MinimumValue=valC3-0.3,
                      MaximumValue=valC3+0.3)
# Although CNCS doesn't use its monitors, this is how instruments that do need
# to call the algorithm.
ws = DgsReduction(SampleInputWorkspace=ws, SampleInputMonitorWorkspace=monitor,
                  IncidentBeamNormalisation="ByCurrent", SofPhiEIsDistribution=False)
w = ws[0]
print("Workspace type = {}".format(w.id()))
print("Number of events = {}".format(w.getNumberEvents()))

Output:

Workspace type = EventWorkspace
Number of events = 2178

Categories: AlgorithmIndex | Workflow\Inelastic

Source

C++ header: DgsReduction.h

C++ source: DgsReduction.cpp