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CentroidPeaksMD v2¶
Summary¶
Find the centroid of single-crystal peaks in a MDEventWorkspace, in order to refine their positions.
See Also¶
Properties¶
Name |
Direction |
Type |
Default |
Description |
|---|---|---|---|---|
InputWorkspace |
Input |
Mandatory |
An input MDEventWorkspace. |
|
PeakRadius |
Input |
number |
1 |
Fixed radius around each peak position in which to calculate the centroid. |
PeaksWorkspace |
Input |
IPeaksWorkspace |
Mandatory |
A PeaksWorkspace containing the peaks to centroid. |
OutputWorkspace |
Output |
IPeaksWorkspace |
Mandatory |
The output PeaksWorkspace will be a copy of the input PeaksWorkspace with the peaks’ positions modified by the new found centroids. |
Description¶
This algorithm starts with a PeaksWorkspace containing the expected positions of peaks in reciprocal space. It calculates the centroid of the peak by calculating the average of the coordinates of all events within a given radius of the peak, weighted by the weight (signal) of the event.
Usage¶
Example - CentroidPeaksMD:
The code iteslef works but disabled from doc tests as takes too long to complete. User should provide its own event nexus file instead of TOPAZ_3132_event.nxs used within this example. The original TOPAZ_3132_event.nxs file is available in Mantid system tests repository.
The example shows how applying centroid peaks changes the peak posisions previously calculated by FindPeaksMD algorithm.
1def print_WSDifference(pTWS1,pTWS2,nRows):
2 '''Method to print difference between two table workspaces before and after applying CentroidPeaks'''
3 # columns to compare
4 tab_names=['RunNumber','DetID','Energy','DSpacing','QLab','QSample']
5 common = tab_names[0:2];
6 long = tab_names[-2:];
7
8 for name in tab_names:
9 if name in common :
10 print("| {0:>10} ".format(name))
11 else:
12 if name in long:
13 print("|FindPeaksMD found (old):{0:>7} |IntegrEllipsoids (new): {0:>7} ".format(name))
14 else:
15 ntp = name;
16 if len(ntp )>6:
17 ntp = ntp[0:6]
18 print("| old {0:>6} | new {0:>6} ".format(ntp))
19 print("|\n" )
20
21 for i in xrange(0,nRows):
22 for name in tab_names:
23 col1 = pTWS1.column(name);
24 data1_toPr=col1[i]
25 col2 = pTWS2.column(name);
26 data2_toPr=col2[i]
27 if name in common :
28 print("| {0:>10} ".format(data1_toPr))
29 else:
30 if name in long:
31 print("| {0:>30} | {1:>30} ".format(data1_toPr,data2_toPr))
32 else:
33 print("| {0:>10.2f} | {1:>10.2f} ".format(data1_toPr,data2_toPr))
34
35 print("|\n ")
36
37# load test workspace
38Load(Filename=r'TOPAZ_3132_event.nxs',OutputWorkspace='TOPAZ_3132_event',LoadMonitors='1')
39
40# build peak workspace necessary for IntegrateEllipsoids algorithm to work
41ConvertToMD(InputWorkspace='TOPAZ_3132_event',QDimensions='Q3D',dEAnalysisMode='Elastic',Q3DFrames='Q_sample',LorentzCorrection='1',OutputWorkspace='TOPAZ_3132_md',\
42MinValues='-25,-25,-25',MaxValues='25,25,25',SplitInto='2',SplitThreshold='50',MaxRecursionDepth='13',MinRecursionDepth='7')
43
44# get initial peak workspace
45peaks=FindPeaksMD(InputWorkspace='TOPAZ_3132_md',PeakDistanceThreshold='0.37680',MaxPeaks='50',DensityThresholdFactor='100',OutputWorkspace='TOPAZ_3132_peaks')
46
47# refine peaks position with centroid peaks
48peaks2=CentroidPeaksMD(InputWorkspace='TOPAZ_3132_md', PeaksWorkspace='TOPAZ_3132_peaks', OutputWorkspace='TOPAZ_3132_peaks2')
49
50print_WSDifference(peaks,peaks2,10)
Output:
1| RunNumber | DetID | old Energy | new Energy | old DSpaci | new DSpaci |FindPeaksMD found (old): QLab |IntegrEllipsoids (new): QLab |FindPeaksMD found (old):QSample |IntegrEllipsoids (new): QSample |
2| 3132 | 1124984 | 8.49 | 10.39 | 2.02 | 1.93 | [1.57771,1.21779,2.37854] | [1.9157,1.15022,2.37669] | [2.99396,0.815958,0.00317344] | [3.13041,0.861402,0.316416] |
3| 3132 | 1156753 | 18.82 | 18.87 | 1.30 | 1.29 | [2.48964,1.45725,3.88666] | [2.50792,1.41823,3.91448] | [4.52618,1.71025,0.129461] | [4.52916,1.75746,0.149293] |
4| 3132 | 1141777 | 28.09 | 29.63 | 1.05 | 1.04 | [2.60836,2.31423,4.86391] | [2.9387,2.15218,4.7974] | [5.69122,1.79492,-0.452799] | [5.72802,1.86148,-0.0867018] |
5| 3132 | 1125241 | 33.86 | 32.09 | 1.01 | 1.01 | [3.15504,2.42573,4.75121] | [3.12135,2.20547,4.87426] | [5.97829,1.63473,0.0118744] | [5.9025,1.87759,0.0200907] |
6| 3132 | 1170598 | 34.12 | 32.63 | 0.95 | 0.96 | [3.43363,1.70178,5.39301] | [3.2557,1.75038,5.41104] | [6.07726,2.59962,0.281759] | [6.02352,2.57854,0.105647] |
7| 3132 | 1214951 | 22.79 | 19.55 | 1.68 | 1.67 | [2.73683,1.43808,2.11574] | [2.60506,1.43592,2.30563] | [3.5786,0.470838,1.00329] | [3.62222,0.607039,0.821705] |
8| 3132 | 1207827 | 27.89 | 29.54 | 1.32 | 1.31 | [2.80324,2.29519,3.09134] | [2.99683,2.18047,3.05302] | [4.71517,0.554412,0.37714] | [4.72528,0.607846,0.598834] |
9| 3132 | 1232949 | 53.28 | 57.02 | 0.93 | 0.93 | [4.29033,2.63319,4.46168] | [4.40869,2.69431,4.34027] | [6.52658,1.27985,1.00646] | [6.5525,1.15043,1.12919] |
10| 3132 | 1189484 | 63.42 | 60.85 | 0.96 | 0.96 | [4.02414,3.39659,3.83664] | [4.15914,3.15181,3.95843] | [6.4679,0.298896,0.726133] | [6.46553,0.557683,0.887368] |
11| 3132 | 1218337 | 79.81 | 87.16 | 0.77 | 0.77 | [4.96622,3.61607,5.32554] | [5.17998,3.67105,5.16175] | [7.99244,1.19363,0.892655] | [8.03942,1.03829,1.11448] |
Categories: AlgorithmIndex | MDAlgorithms\Peaks
Source¶
C++ header: CentroidPeaksMD2.h
C++ source: CentroidPeaksMD2.cpp