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Re: [lammps-users] RATTLE in version 2017!
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Re: [lammps-users] RATTLE in version 2017!


From: Hai Hoang <hhoang052@...24...>
Date: Wed, 18 Oct 2017 16:50:14 +0200

Dear Axel,

Thank you so much for your quick response. Versions I have tested lammps-10Aug15 and lammps-31Mar17 (even the current one).


 

On Wed, Oct 18, 2017 at 4:19 PM, Axel Kohlmeyer <akohlmey@...24...> wrote:
you can see which changes were done to fix rattle by examining the
file history in the LAMMPS git repository:
https://github.com/lammps/lammps/commits/master/src/RIGID/fix_rattle.cpp

for more details, you should contact the author of this style.

please note, that the information you provide is very vague (including
the LAMMPS version, there were lots of released LAMMPS versions in
both 2015 and 2017).
please check out: http://lammps.sandia.gov/guidelines.html

axel.

On Wed, Oct 18, 2017 at 4:25 AM, Hai Hoang <hhoang052@...24...> wrote:
> Dear all,
>
> I have employed RATTLE method to constrain the rigid bonds in water
> molecules and to count the number of freedom for generating initial
> velocities of atoms as:
>
> --------------------------------
>     # Fix rigid bonds
>     fix shake_bond    fluid shake 1.0e-5 200 0 b 1 a 1
>
>     # Creat the velocity
>     velocity fluid create ${Temp_imp} ${Iseed_imp} mom yes rot yes dist
> gaussian
>
>     # Transient duration
>     timestep ${dt}
>     reset_timestep 0
>
>     fix npt_md fluid npt temp ${Temp_imp} ${Temp_imp} ${Damp_temp} iso
> ${Press_imp} ${Press_imp} ${Damp_press}
> ---------------------------------
>
>  If I used versions 2015, it works well, i.e. it exports the temperature at
> t=0 is exactly equal to ${Temp_imp}. However, with version 2017, it shows
> that at t=0, the temperature does not remove number of constraints in
> computing the temperature, i.e. temperature at t=0 is not equal ${Temp_imp}.
>
> In addition, use of RATTLE in version 2017 is not stable, i.e. i mean that
> all input and script are the same, but run independently one of them has
> error, others are not. Such situations donot occur with version 2015.
>
> (Note that: if use of SHAKE, all are correct with both versions 2015 and
> 2017)
>
> So, anyone can tell me what changed in RATTLE of version 2015 and 2017? Or
> explain me what happen?
>
> Thanks,
>
>
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--
Dr. Axel Kohlmeyer  akohlmey@...43...4...  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.