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Table of Contents
Name | Direction | Type | Default | Description |
---|---|---|---|---|
Filename | Input | list of str lists | Mandatory | Files to combine in reduction. Allowed extensions: [‘_event.nxs’, ‘.nxs.h5’] |
MaxChunkSize | Input | number | 0 | Specify maximum Gbytes of file to read in one chunk. Default is whole file. |
FilterBadPulses | Input | number | 0 | Filter out events measured while proton charge is more than 5% below average |
AbsorptionWorkspace | Input | MatrixWorkspace | Divide data by this Pixel-by-pixel workspace | |
CacheDir | Input | string | Directory storing cache files for reuse, in-lieu of repetitive, time-consuming calculations | |
OutputWorkspace | Output | MatrixWorkspace | Mandatory | Combined output workspace |
UnfocussedWorkspace | Output | MatrixWorkspace | Treated data in d-spacing before focussing (optional). This will likely need rebinning. | |
Characterizations | Input | TableWorkspace | Characterizations table | |
CalFileName | Input | string | The name of the calibration file with offset, masking, and grouping data. Allowed extensions: [‘.h5’, ‘.hd5’, ‘.hdf’, ‘.cal’] | |
GroupFilename | Input | string | Overrides grouping from CalFileName. Allowed extensions: [‘.xml’, ‘.cal’] | |
GroupingWorkspace | InOut | GroupingWorkspace | Optional: A GroupingWorkspace giving the grouping info. | |
CalibrationWorkspace | InOut | TableWorkspace | Optional: A Workspace containing the calibration information. Either this or CalibrationFile needs to be specified. | |
OffsetsWorkspace | Input | OffsetsWorkspace | Optional: An OffsetsWorkspace giving the detector calibration values. | |
MaskWorkspace | InOut | MaskWorkspace | Optional: A workspace giving which detectors are masked. | |
MaskBinTable | Input | TableWorkspace | Optional: A workspace giving pixels and bins to mask. | |
Params | Input | dbl list | A comma separated list of first bin boundary, width, last bin boundary. Optionally this can be followed by a comma and more widths and last boundary pairs. Negative width values indicate logarithmic binning. | |
ResampleX | Input | number | 0 | Number of bins in x-axis. Non-zero value overrides “Params” property. Negative value means logarithmic binning. |
Dspacing | Input | boolean | True | Bin in Dspace. (True is Dspace; False is TOF) |
PreserveEvents | Input | boolean | True | If the InputWorkspace is an EventWorkspace, this will preserve the full event list (warning: this will use much more memory!). |
RemovePromptPulseWidth | Input | number | 0 | Width of events (in microseconds) near the prompt pulse to remove. 0 disables |
CompressTolerance | Input | number | 1e-05 | Compress events (in microseconds) within this tolerance. (Default 1e-5) |
CompressWallClockTolerance | Input | number | Optional | The tolerance (in seconds) on the wall-clock time for comparison. Unset means compressing all wall-clock times together disabling pulsetime resolution. |
CompressStartTime | Input | string | An ISO formatted date/time string specifying the timestamp for starting filtering. Ignored if WallClockTolerance is not specified. Default is start of run | |
LorentzCorrection | Input | boolean | False | Multiply each spectrum by sin(theta) where theta is half of the Bragg angle |
UnwrapRef | Input | number | 0 | Reference total flight path for frame unwrapping. Zero skips the correction |
LowResRef | Input | number | 0 | Reference DIFC for resolution removal. Zero skips the correction |
LowResSpectrumOffset | Input | number | -1 | Offset on spectrum No of low resolution spectra from high resolution one. If negative, then all the low resolution TOF will not be processed. Otherwise, low resolution TOF will be stored in an additional set of spectra. If offset is equal to 0, then the low resolution will have same spectrum Nos as the normal ones. Otherwise, the low resolution spectra will have spectrum IDs offset from normal ones. |
ReductionProperties | Input | string | __powdereduction | |
DMin | Input | dbl list | Minimum for Dspace axis. (Default 0.) | |
DMax | Input | dbl list | Maximum for Dspace axis. (Default 0.) | |
DeltaRagged | Input | dbl list | Step parameter for rebin | |
TMin | Input | number | Optional | Minimum for TOF axis. Defaults to 0. |
TMax | Input | number | Optional | Maximum for TOF or dspace axis. Defaults to 0. |
CropWavelengthMin | Input | number | 0 | Crop the data at this minimum wavelength. Overrides LowResRef. |
CropWavelengthMax | Input | number | Optional | Crop the data at this maximum wavelength. Forces use of CropWavelengthMin. |
PrimaryFlightPath | Input | number | -1 | If positive, focus positions are changed. (Default -1) |
SpectrumIDs | Input | int list | Optional: Spectrum Nos (note that it is not detector ID or workspace indices). | |
L2 | Input | dbl list | Optional: Secondary flight (L2) paths for each detector | |
Polar | Input | dbl list | Optional: Polar angles (two thetas) for detectors | |
Azimuthal | Input | dbl list | Azimuthal angles (out-of-plain) for detectors | |
FrequencyLogNames | Input | str list | SpeedRequest1,Speed1,frequency,skf1.speed | Candidate log names for frequency |
WaveLengthLogNames | Input | str list | LambdaRequest,lambda,skf12.lambda | Candidate log names for wave length |
This is a workflow algorithm that wraps
AlignAndFocusPowder to perform a double loop over files
with chunks, accumulating the result. The additional properties from
what is allowed in AlignAndFocusPowder is for how the file
is loaded (e.g. MaxChunkSize
and FilterBadPulses
), an optional
Characterizations
table
, and
an optional AbsorptionWorkspace
. The AbsorptionWorkspace
should be in units of Wavelength
for every detector pixel and is
divided from the chunk after loaded. For all other information, see
AlignAndFocusPowder.
In broad terms, this algorithm is the pseudo-code:
for filename in filenames:
cachefile = CreateCacheFilename(filename, ...)
if cachefile exists:
wksp_single = LoadNexusProcessed(cachefile)
else:
for chunk in DetermineChunking(filename):
wksp_single_chunk = Load(chunk)
wksp_single_chunk = AlignAndFocusPowder(wksp_single_chunk, ...)
# accumulate chunks into wksp_single
SaveNexusProcess(wksp_single, cachefile)
# accumulate data from files into OutputWorkspace
Algorithms used by this are:
Categories: AlgorithmIndex | Diffraction\Reduction
Python: AlignAndFocusPowderFromFiles.py (last modified: 2021-02-12)