The ABINIT Users Mailing List ( CLOSED )

["Matteo Giantomassi" <Matteo.Giantomassi@uclouvain.be>]

 Hello abinists,
>
> I have come upon a strange behavior in abinit (not the first, of course)
> and
> was wondering if anyone had heard of it or an explanation (v5.6 on opteron
> 64 bit RHEL, g95 compiled, sequential).
>
> In converging a ground state for graphene (what else), I need to use only
> symmorphic symmetry operations. The strange behavior is that, without the
> non-symmorphic symmetry operations, abinit does not converge the
> wavefunctions below 1.e-13 or so (even after 200 steps), and the
> eigenvalues
> are not converged below mHa accuracy. With all the symops the convergence
> down to tolwfr 1.e-20 is effortless. Why the difference? Numerical noise
> is
> one possibility, but plenty of symops are left in the calculation...
>
 Hi, Matthieu

 I've never encountered such a kind of problem but
 it might be related to a partial fulfillment of the symmetry properties
 of the density and of the generated potentials.
 Do you have the same number of k-points in the IBZ when non-symmorphic
 operations are removed?

 Just for curiosity: are you pruning non-symmorphic ops because you want to
 generate a KSS file for GW calculations with abinit?
 In this case please note that symmorphi=0 is not mandatory anymore
 as the GW part is now able to handle non-symmorphic space groups.

 Cheers,
 Matteo