[Pw_forum] pw.x not able to specity initial ion velocities

[Konstantin Kudin]

 Actually, the velocity input appears to be almost purely unsupported.
Consider these lines in read_cards.f90 :

       ELSE IF ( TRIM(card) == 'ATOMIC_VELOCITIES' ) THEN
          !
          CALL card_ion_velocities( input_line )
          IF ( ( prog == 'PW' .OR. prog == 'CP' ) .AND. ionode ) &
             WRITE( stdout,'(A)') 'Warning: card '//trim(input_line)//'
ignored'

 What this piece of code is saying is that for either PW or CP the
ATOMIC_VELOCITIES card is ignored (when is it supported then?). While
this of course does not guarantee that this message is reliable, my own
experience with trying to input velocities into CP seems to confirm the
lack of such functionality.

 Kostya

 
 

--- Axel Kohlmeyer <akohlmey at cmm.upenn.edu> wrote:

> tim,
> 
> please check your input and check whether the number of
> lines for the atoms and velocities both match the 'nat' variable.
> if they do please post your input file, so we can examine it.
> 
> thanks,
>     axel.
> 
> On 8/23/06, Tim Teatro <timtro at gmail.com> wrote:
> > Hello all.
> >
> > This is probably an easy one. I'm sorry to bother you with it.
> >
> > When I try to specify starting velocities for ions in a pw.x input
> file
> > (obviously for dynamics), I set ion_velocities = 'from_input' and
> specify an
> > ATOMIC_VELOCITIES card. When it runs, I get a warning that a card
> is
> > ignored. The ignored card is (for whatever reason) the last entry
> in my
> > ATOMIC_VELOCITIES card ( Species(n)   Vx(n)  Vy(n)   Vz(n) ), and
> the
> > temperature calculated at the end of the first step certainly does
> not
> > reflect the temperature that the system should have given the
> velocities I
> > specified.
> >
> > I looked in the source code, and according to read_cards.f90, the
> program
> > should hit the velocity card and read of the next nat lines, so I
> have no
> > idea why it would try to read off my last velocity entry as a card.
> There
> > also doesn't seem to be any comments that this bit of code is
> restricted to
> > cp.x or something. But is it?
> >
> > Thanks!
> >
> 
> 
> -- 
>
=======================================================================
> Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu  
> http://www.cmm.upenn.edu
>   Center for Molecular Modeling   --   University of Pennsylvania
> Department of Chemistry, 231 S.34th Street, Philadelphia, PA
> 19104-6323
> tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel:
> 1-215-898-5425
>
=======================================================================
> If you make something idiot-proof, the universe creates a better
> idiot.
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