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PeaksInRegion v1¶

../_images/ImageNotFound.png — Enable screenshots using DOCS_SCREENSHOTS in CMake¶

Summary ¶

Find peaks intersecting a box region.

Properties ¶

Name	Direction	Type	Default	Description
CheckPeakExtents	Input	boolean	False	Include any peak in the region that has a shape extent extending into that region.
InputWorkspace	Input	PeaksWorkspace	Mandatory	An input peaks workspace.
CoordinateFrame	Input	string	Mandatory	What coordinate system to use for intersection criteria? DetectorSpace: Real-space coordinates. Q (lab frame): Wave-vector change of the lattice in the lab frame. Q (sample frame): Momentum in the sample frame. HKL. Allowed values: [‘Detector space’, ‘Q (lab frame)’, ‘Q (sample frame)’, ‘HKL’]
PeakRadius	Input	number	0	Effective peak radius in CoordinateFrame
OutputWorkspace	Output	TableWorkspace	Mandatory	An output table workspace. Two columns. Peak index into input workspace, and boolean, where true is for positive intersection.
Extents	Input	dbl list	-50,50	A comma separated list of min, max for each dimension, specifying the extents of each dimension. Optional, default +-50 in each dimension.

Description ¶

Determines which peaks intersect a defined box region in either QLab, QSample or HKL space. Similar to PeaksOnSurface v1.

Usage ¶

Example - Peaks inside and outside of a defined region

# Load an MDEventWorkspace (QLab) containing some SC diffration peaks
mdew = Load("TOPAZ_3680_5_sec_MDEW.nxs")
# Find some peaks. These are all unindexed so will have HKL = [0,0,0]
peaks = FindPeaksMD(InputWorkspace=mdew, MaxPeaks=1)

# Find peaks in region when the Peak sits in the centre of a box
in_box_table = PeaksInRegion(peaks, CoordinateFrame='HKL', PeakRadius=0.1, Extents=[-1.0,1.0,-1.0,1.0,-1.0,1.0], CheckPeakExtents=True)
print("{{'Distance': {Distance}, 'PeakIndex': {PeakIndex}, 'Intersecting': {Intersecting}}}".format(**in_box_table.row(0)))

# Find peaks in region when the peak is just outside the box (by radius)
just_outside_box_table = PeaksInRegion(peaks, CoordinateFrame='HKL', PeakRadius=0.999, Extents=[1.0,2.0,-1.0,1.0,-1.0,1.0], CheckPeakExtents=True)
print("{{'Distance': {Distance}, 'PeakIndex': {PeakIndex}, 'Intersecting': {Intersecting}}}".format(**just_outside_box_table.row(0)))

# Find peaks in region when the peak is just inside the box (by radius)
just_intersecting_box_table = PeaksInRegion(peaks, CoordinateFrame='HKL', PeakRadius=1.00, Extents=[1.0,2.0,-1.0,1.0,-1.0,1.0], CheckPeakExtents=True)
print("{{'Distance': {Distance}, 'PeakIndex': {PeakIndex}, 'Intersecting': {Intersecting}}}".format(**just_intersecting_box_table.row(0)))

Output:

{'Distance': 0.0, 'PeakIndex': 0, 'Intersecting': True}
{'Distance': -1.0, 'PeakIndex': 0, 'Intersecting': False}
{'Distance': -1.0, 'PeakIndex': 0, 'Intersecting': True}

Categories: AlgorithmIndex | Crystal\Peaks