returns whether symmetry is defined
Syntax
sym = symmetry(obj)
Description
sym = symmetry(obj) returns true if equivalent couplings are
generated based on the crystal space group and all matrices (interaction,
anisotropy and g-tensor) are transformed according to the symmetry
operators. If false, equivalent couplings are generated based on bond
length, equivalent matrices won’t be transformed (all identical).
To switch between the two behaviour use spinw.gencoupling with the
forceNoSym parameter set to true. To remove all symmetry operators
use spinw.nosym.