def symmetryFactor(self):
"""
:return: the symmetry factor used in the normalization of structure
factors or intensities. It is equal to the number of
space group symmetry operations that map a reflection
to itself.
:rtype: int
"""
sg = self.crystal.space_group
equivalents = sg.symmetryEquivalentMillerIndices(self.array)[0]
return N.int_sum(N.alltrue(N.array(equivalents) == self.array, axis=1))
def isCentric(self, _equivalents=None):
"""
:return: True if the reflection is centric (i.e. equivalent to
the reflection (-h, -k, -l) by space group symmetry
operations)
:rtype: bool
"""
sg = self.crystal.space_group
if _equivalents is None:
_equivalents = sg.symmetryEquivalentMillerIndices(self.array)[0]
return N.int_sum(N.alltrue(N.array(_equivalents) == -self.array,
axis=1)) > 0
