Remove symmetry elements for SaveINS

[zjmorgan]

Description of work

SaveINS incorrectly includes all symmetry elements and should not include identity, inversion, or any that can be generated by the lattice centering translations.

Summary of work

Redundant symmetry elements that can be generated by the underlying centering condition or rotoinversion should be removed. In addition, identity does not need to be included.

To test:

Run the additional system tests. Or, run this example. Choose any space group. Go to link https://cci.lbl.gov/cctbx/shelx.html and enter the same space group symbol. Cross check that it gives the same symmetry operators. Order does not matter.

# import mantid algorithms, numpy and matplotlib
from mantid.simpleapi import *
import matplotlib.pyplot as plt
import numpy as np

ws = CreateSampleWorkspace(OutputWorkspace='ws', NumBanks=1, BankPixelWidth=1, BinWidth=20000)  # 1 bin
SetUB(Workspace=ws, a=7.6508, b=13.2431, c=11.6243, alpha=90, beta=104.1183, gamma=90)
ndensity = 4 / ws.sample().getOrientedLattice().volume()  # number density with 4 formula units per u.c
SetSample(InputWorkspace=ws, Material={'ChemicalFormula': 'C12 H9 N3 O2 S1',
          'SampleNumberDensity': ndensity})
SaveINS(InputWorkspace=ws, Filename='/tmp/SHELX.ins', Spacegroup='I a -3 d', UseNaturalIsotopicAbundances=True)

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[sf1919]

Can we get a milestone on this so we know whether we're trying to get it into v6.12 or not?

[thomashampson]

I think this needs to move a level deeper, into the Bugfixes folder