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LoadMask v1¶

Summary ¶

Load file containing masking information to a SpecialWorkspace2D (masking workspace).

Properties ¶

Name	Direction	Type	Default	Description
Instrument	Input	string	Mandatory	The name of the instrument to apply the mask.
InputFile	Input	string	Mandatory	Masking file for masking. Supported file format is XML and ISIS ASCII. Allowed extensions: [‘.xml’, ‘.msk’]
RefWorkspace	Input	MatrixWorkspace		The name of the workspace wich defines instrument and spectra, used as the source of the spectra-detector map for the mask to load. The instrument, attached to this workspace has to be the same as the one specified by ‘Instrument’ property
OutputWorkspace	Output	MaskWorkspace	Masking	Output Masking Workspace

Description ¶

This algorithm is used to load a masking file, which can be in XML format (defined later in this page) or old-styled calibration file. The Instrument can be a IDF.

Definition of Mask ¶

If a pixel is masked, it means that the data from this pixel won’t be used. In the masking workspace (i.e., SpecialWorkspace2D ), the corresponding value is 1.
If a pixel is NOT masked, it means that the data from this pixel will be used. In the masking workspace (i.e., SpecialWorkspace2D ), the corresponding value is 0.

File Format ¶

XML File Format ¶

Example 1:

<?xml version="1.0" encoding="UTF-8" ?>
<detector-masking>
 <group>
  <detids>3,34-44,47</detids>
  <component>bank123</component>
  <component>bank124</component>
 </group>
</detector-masking>

ISIS File Format ¶

Example 2:

1-3 62-64
65-67 126-128
129-131 190-192
193-195 254-256
257-259 318-320
321-323 382-384
385 387 446 448
... ...

All the integers in file of this format are spectrum Numbers to mask. Two spectrum Numbers with “-” in between indicate a continuous range of spectra to mask. It does not matter if there is any space between integer number and “-”. There is no restriction on how the line is structured. Be noticed that any line starting with a non-digit character, except space, will be treated as a comment line.

This algorithm loads masking file to a SpecialWorkspace2D/MaskWorkspace.

Supporting

* Component ID --> Detector IDs --> Workspace Indexes
* Detector ID --> Workspace Indexes
* Spectrum Number --> Workspace Indexes

When a spectra mask (ISIS) is used on multiple workspaces, the same masking is produced only if all masked workspaces have the same spectra-detector map. When mask is generated for one workspace and applied to workspace with different spectra-detector mapping, the same masking can be produced by using Workspace option, using this workspace as the source of the spectra-detector mapping. See the Spectra mask usage sample below.

Usage ¶

Note

To run these usage examples please first download the usage data, and add these to your path. In Mantid this is done using Manage User Directories.

ws = Load('HYS_11092_event.nxs')
mask = LoadMask('HYS', 'HYS_mask.xml')
# To check if mask loaded, apply it
MaskDetectors(ws, MaskedWorkspace=mask)
# One can alternatively do
# ws.maskDetectors(MaskedWorkspace=mask)

# Check some pixels
print("Is detector 0 masked: {}".format(ws.getDetector(0).isMasked()))
print("Is detector 6245 masked: {}".format(ws.getDetector(6245).isMasked()))
print("Is detector 11464 masked: {}".format(ws.getDetector(11464).isMasked()))
print("Is detector 17578 masked: {}".format(ws.getDetector(17578).isMasked()))
print("Is detector 20475 masked: {}".format(ws.getDetector(20475).isMasked()))

Output:

Is detector 0 masked: True
Is detector 6245 masked: True
Is detector 11464 masked: False
Is detector 17578 masked: False
Is detector 20475 masked: True

Example: Using reference workspace with Spectra Mask

# Load workspace with real spectra-derector mask
rws = Load(Filename=r'MAR11001.raw', OutputWorkspace='realWs',InlcudeMonitors=True);

# Create sample mask
MaskDetectors(Workspace=rws, SpectraList='10,11,12,13,100,110,120,130,140,200,300')
masked_list = ExportSpectraMask(rws,'SampleMask')
file2remove = os.path.join(config.getString('defaultsave.directory'),'SampleMask.msk')

#

# Load sample  spectra mask using 1:1 instrument
mask1to1ws= LoadMask('MARI','SampleMask.msk')

# Apply spectra mask using real workspace spectra-detector map.
# Note that rws does not need to be masked like its here, We use it masked here only to avoid overhead of loading it again
# it just needs to contain the same spectra-detector map as the initial workspace
# you may want to try rows below to be sure:
#rws1 = Load(Filename=r'MAR11001.raw', OutputWorkspace='realWs1',InlcudeMonitors=True);

# Load Mask using  instrument and spectra-detector map provided with source workspace
maskRealSDM=LoadMask('MARI','SampleMask.msk',RefWorkspace=rws)

# Clear up rubbish
os.remove(file2remove)

# See the difference:
nhist = mask1to1ws.getNumberHistograms()
Sig0Masked = []
Det0Masked= []
MaskedSp1to1 = []
MaskedDet1to1= []
MaskedSp_R  = []
MaskedDet_R= []
for ind in range(0,nhist):
    try:
        det = rws.getDetector(ind)
        if det.isMasked():
            Sig0Masked.append(ind)
            Det0Masked.append(det.getID())
        #  1:1 map generated from instrument definitions
        if mask1to1ws.readY(ind)[0]>0.5:
            det = mask1to1ws.getDetector(ind)
            MaskedSp1to1.append(ind)
            MaskedDet1to1.append(det.getID())
        # Real spectra-detector map:
        if maskRealSDM.readY(ind)[0]>0.5:
            det = maskRealSDM.getDetector(ind)
            MaskedSp_R.append(ind)
            MaskedDet_R.append(det.getID())
    except:
        pass
print("*** ************************************ **********************************************")
print("*** Masked Spec. Id(s):  {0}".format(masked_list))
print( "*** Initial workspace masking parameters **********************************************")
print("Masked Spectra Numbers:  {}".format(Sig0Masked))
print("Masked Detector IDs   :  {}".format(Det0Masked))
print("*** One to one mask workspace has masked the same spectra numbers but different detectors")
print("ws 1to1 Masked spectra:  {}".format(MaskedSp1to1))
print("ws 1to1 Masked DedIDs :  {}".format(MaskedDet1to1))
print("*** Real spectra-det-map workspace has masked different spectra numbers but the same detectors")
print("ws RSDM Masked spectra:  {}".format(MaskedSp_R))
print("ws RSDM Masked DedIDs :  {}".format(MaskedDet_R))
print("*** indeed the same:")
Det0Masked.sort()
MaskedDet_R.sort()
print("sorted initial DetIDs :  {}".format(Det0Masked))
print("sorted RSDM    DedIDs :  {}".format(MaskedDet_R))
print("*** ************************************ **********************************************")
print("*** note spectra with id 4 is a monitor, not present in the masking workspaces")
print("*** ************************************ **********************************************")

Output:

*** ************************************ **********************************************
*** Masked Spec. Id(s):  [  4  10  11  12  13 100 110 120 130 140 200 300]
*** Initial workspace masking parameters **********************************************
Masked Spectra Numbers:  [9, 10, 11, 12, 99, 109, 119, 129, 139, 199, 299]
Masked Detector IDs   :  [4106, 4107, 4108, 4109, 4608, 4702, 4712, 4806, 4816, 2220, 2524]
*** One to one mask workspace has masked the same spectra numbers but different detectors
ws 1to1 Masked spectra:  [9, 10, 11, 12, 99, 109, 119, 129, 139, 199, 299]
ws 1to1 Masked DedIDs :  [1110, 1111, 1112, 1113, 1401, 1411, 1421, 1431, 1509, 1705, 2201]
*** Real spectra-det-map workspace has masked different spectra numbers but the same detectors
ws RSDM Masked spectra:  [318, 418, 787, 788, 789, 790, 877, 887, 897, 907, 917]
ws RSDM Masked DedIDs :  [2220, 2524, 4106, 4107, 4108, 4109, 4608, 4702, 4712, 4806, 4816]
*** indeed the same:
sorted initial DetIDs :  [2220, 2524, 4106, 4107, 4108, 4109, 4608, 4702, 4712, 4806, 4816]
sorted RSDM    DedIDs :  [2220, 2524, 4106, 4107, 4108, 4109, 4608, 4702, 4712, 4806, 4816]
*** ************************************ **********************************************
*** note spectra with id 4 is a monitor, not present in the masking workspaces
*** ************************************ **********************************************

Categories: AlgorithmIndex | DataHandling\Masking | Transforms\Masking

Source ¶

C++ header: LoadMask.h

C++ source: LoadMask.cpp