[Pw_forum] error on phonon calculation (root not converged)

Paolo Giannozzi giannozz at nest.sns.it
Fri Apr 7 16:39:36 CEST 2006

On Friday 07 April 2006 12:21, Eyvaz Isaev wrote:

> Try small alpha_mix, say 0.1. Besides, your tr2_ph =
> 1e-18 seems to be extremly small. By default it is
> tr2_ph = 1e-10. Try this one and then check what
> happens for reduced threshold.

this may actually work, but the problem that shows up in
Liping's output is rather strange and nasty. The self-consistent
procedure seems to converge quite nicely: |ddv_scf|^2 goes
down towards the threshold, then it starts to go up to crazy
values. Why, I don't know, and I am afraid there is very little
one can do when this kind of behavior occurs in the middle
of a long job without any apparent reason

Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513 
Piazza dei Cavalieri 7      I-56126 Pisa, Italy

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