.. algorithm::

.. summary::

.. relatedalgorithms::

.. properties::

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

Given a PeaksWorkspace with a :ref:`UB matrix <Lattice>` 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
:ref:`UB matrix <Lattice>` associated with the sample in the PeaksWorkspace
will be updated to a :ref:`UB matrix <Lattice>` corresponding to the selected
cell AND the peaks will be re-indexed using the new :ref:`UB matrix <Lattice>`.
The output transformation matrix :math:`M` will change :math:`UB` to :math:`UBM^{-1}`
and map each :math:`(HKL)` vector to :math:`M(HKL)`. It can be further
used by the :ref:`TransformHKL <algm-TransformHKL>` algorithm.
NOTE: The possible conventional cells, together with the corresponding errors
in the cell scalars can be seen by running the
:ref:`ShowPossibleCells <algm-ShowPossibleCells>` algorithm, provided the
stored :ref:`UB matrix <Lattice>` corresponds to a Niggli reduced cell.

This algorithm is based on the paper: Alan D. Mighell, *Lattice
Symmetry and Identification—The Fundamental Role of Reduced Cells in
Materials Characterization.* Journal of research of the National
Institute of Standards and Technology **106.6** (2001): 983, available
from: `nvlpubs <http://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

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.. sourcelink::