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SelectCellWithForm-v1.rst 2.21 KiB
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.. algorithm::

.. summary::

.. alias::

.. properties::

Description
-----------

Given a PeaksWorkspace with a UB matrix corresponding to a Niggli
reduced cell, this algorithm will allow the user to select a
conventional cell corresponding to a specific form number from the
Mighell paper. If the apply flag is not set, the information about the
selected cell will just be displayed. If the apply flag is set, the UB
matrix associated with the sample in the PeaksWorkspace will be updated
to a UB corresponding to the selected cell AND the peaks will be
re-indexed using the new UB matrix. NOTE: The possible conventional
cells, together with the corresponding errors in the cell scalars can be
seen by running the ShowPossibleCells algorithm, provided the stored UB
matrix corresponds to a Niggli reduced cell.

This algorithm is based on the paper: "Lattice Symmetry and
Identification -- The Fundamental Role of Reduced Cells in Materials
Characterization", Alan D. Mighell, Vol. 106, Number 6, Nov-Dec 2001,
Journal of Research of the National Institute of Standards and
Technology, available from: `nvlpubs <nvlpubs.nist.gov/nistpubs/jres/106/6/j66mig.pdf>`_.
Usage
-----
 
**Example:**
 
.. testcode:: ExSelectCellWithForm
   
   ws=LoadIsawPeaks("TOPAZ_3007.peaks")
   FindUBUsingFFT(ws,MinD=8.0,MaxD=13.0)
   print("Lattice before SelectCellWithForm:")
   lattice = ws.sample().getOrientedLattice()
   print(" ".join("{:.9f}".format(x) for x in [lattice.a(), lattice.b(), lattice.c(),
                   	                        lattice.alpha(), lattice.beta(), lattice.gamma()]))
   SelectCellWithForm(PeaksWorkspace='ws', FormNumber=25, Apply=True)
   print("\nLattice after SelectCellWithForm:")
   lattice = ws.sample().getOrientedLattice()
   print(" ".join("{:.9f}".format(x) for x in [lattice.a(), lattice.b(), lattice.c(),
                   	                        lattice.alpha(), lattice.beta(), lattice.gamma()]))
 
 
Output:
 
.. testoutput:: ExSelectCellWithForm
    Lattice before SelectCellWithForm:
    8.605818643 11.935925461 11.941812766 107.429088323 98.752912466 98.951193475
    Lattice after SelectCellWithForm:
    14.131051152 19.247332564 8.605818643 89.881170675 105.071333770 89.970386662