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AlignAndFocusPowderFromFiles v1

Summary

The algorithm used for reduction of powder diffraction data

See Also

AlignAndFocusPowder

Properties

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

LogAllowList

Input

str list

If specified, only these logs will be loaded from the file. This is passed to LoadEventNexus

LogBlockList

Input

str list

If specified, these logs will not be loaded from the file. This is passed to LoadEventNexus

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

ResonanceFilterUnits

Input

string

Wavelength

Units for resonances to be filtered in. The data will be converted to these units temporarily to filter. Allowed values: [‘Energy’, ‘Wavelength’]

ResonanceFilterLowerLimits

Input

dbl list

Minimum values to filter absorption resonance. This must have same number of values as ResonanceFilterUpperLimits. Default behavior is to not filter.

ResonanceFilterUpperLimits

Input

dbl list

Maximum values to filter absorption resonance. This must have same number of values as ResonanceFilterLowerLimits. Default behavior is to not filter.

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,BL1B:Det:TH:BL:Lambda,freq

Candidate log names for wave length

Description

This is a workflow algorithm that wraps AlignAndFocusPowder to perform a double loop over files with chunks, followed by accumulating the results. 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, the following pseudo-code describes the general concept of this algorithm:

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:

  1. AlignAndFocusPowder v1

  2. CompressEvents v1

  3. ConvertDiffCal v1

  4. ConvertUnits v1

  5. CopyLogs v1

  6. CopySample v1

  7. CreateCacheFilename v1

  8. DeleteWorkspace v1

  9. DetermineChunking v1

  10. Divide v1

  11. EditInstrumentGeometry v1

  12. FilterBadPulses v1

  13. LoadDiffCal v1

  14. Load v1

  15. LoadIDFFromNexus v1

  16. LoadNexusProcessed v1

  17. PDDetermineCharacterizations v1

  18. Plus v1

  19. RebinToWorkspace v1

  20. RemoveLogs v1

  21. RenameWorkspace v1

  22. SaveNexusProcessed v1

Categories: AlgorithmIndex | Diffraction\Reduction

Source

Python: AlignAndFocusPowderFromFiles.py