[Pw_forum] questions on molecular dynamics example

[Eduardo Ariel Menendez P]

Hi Paolo,
I saw these options in the examples of molecular dynamics woth PW. There
is few information in the Doc files and the forum.

    pot_extrapolation='second-order',
    wfc_extrapolation='second-order',

I guessed that extrapolation options would reduce the number of
self-consistent steps in MD steps. However, in the case I am running
(CdTe) he number of self consistent steps at each ionic steps averages
16, regardless of the extrapolation keywords.

Other keyword that I see in the examples is
    disk_io='high',etc,
Is this keyword useful to improve the efficiency of molecular dynamics?

Other issue. I had this error in step 90
     iteration #  4     ecut=    30.00 Ry     beta=0.70
     Davidson diagonalization with overlap
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     from rdiaghg : error #      1986
     info =/= 0
Consulting the manual and the forum I see that it is difficult to find
the cause, and that the first choice is restart
and see what happens. I did it and the calculation just continued without
error. ?Does it allows to discard the possible cause of bad
pseudopotential, and bug of the lapack algorithm, in favor of buggy mahine
optimization of lapack (MKL) ?

Thanks
Eduardo

Eduardo A. Menendez Proupin
Department of Physics
Faculty of Science
University of Chile
Las Palmeras 3425
Ñuñoa, Santiago
Chile
Phone: 56+2+978 74 11
http://fisica.ciencias.uchile.cl/~emenendez/