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FindUBUsingIndexedPeaks v1

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Summary

Calculate the UB matrix from a peaks workspace, containing indexed peaks.

See Also

SetUB, FindUBUsingFFT, FindUBUsingLatticeParameters, FindUBUsingMinMaxD

Properties

Name	Direction	Type	Default	Description
PeaksWorkspace	InOut	IPeaksWorkspace	Mandatory	Input Peaks Workspace
Tolerance	Input	number	0.1	Indexing Tolerance (0.1)
ToleranceForSatellite	Input	number	0.1	Indexing Tolerance for satellite (0.1)
CommonUBForAll	Input	boolean	False	Used when evaluating the uncertainty of modHKL

Description

Given a set of peaks at least three of which have been assigned Miller indices, this algorithm will find the UB matrix, that best maps the integer (h,k,l) values to the corresponding Q vectors. The set of indexed peaks must include three linearly independent Q vectors. The (h,k,l) values from the peaks are first rounded to form integer (h,k,l) values. The algorithm then forms a possibly over-determined linear system of equations representing the mapping from (h,k,l) to Q for each indexed peak. The system of linear equations is then solved in the least squares sense, using QR factorization.

The option CommonUBForAll only effects the calculation of the uncertainty in the modulation UB. If True the UB will be optimized separately for each subset of runs before calculating the error.

Usage

Example:

ws=LoadIsawPeaks("TOPAZ_3007.peaks")
print("After LoadIsawPeaks does the workspace have an orientedLattice: %s" % ws.sample().hasOrientedLattice())

FindUBUsingIndexedPeaks(ws)
print("After FindUBUsingIndexedPeaks does the workspace have an orientedLattice: %s" % ws.sample().hasOrientedLattice())

print(ws.sample().getOrientedLattice().getUB())

Output:

After LoadIsawPeaks does the workspace have an orientedLattice: False
After FindUBUsingIndexedPeaks does the workspace have an orientedLattice: True
[[-0.04542062  0.04061954 -0.01223576]
 [ 0.00140377 -0.00318446  0.11654506]
 [ 0.05749773  0.03223779  0.02737294]]

Categories: AlgorithmIndex | Crystal\UBMatrix

Source

C++ header: FindUBUsingIndexedPeaks.h

C++ source: FindUBUsingIndexedPeaks.cpp