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Re: [lammps-users] (no subject)


From: Axel Kohlmeyer <akohlmey@...24...>
Date: Mon, 9 Oct 2017 06:14:29 -0400

some general comments:

- please make it a habit to use a meaningful subject line on your e-mails. this will significantly increase the chances that people read them and thus your chances to get help
- there is no point in copying steve or me when you send an e-mail to lammps-users. we are both subscribed and will receive e-mails from the list. due to copying us, you just make it more effort to have your e-mail automatically sorted into the proper mail folder.


On Mon, Oct 9, 2017 at 12:57 AM, sanchari bhatt <sanchari789byc@...24...> wrote:
hello users,

i have defined  two regions in my simulation  and ,want to calculate msd(meansquaredisplacement
)for this  two regions,but unable to calculate it separately for cations and anions,as my both region contains cations and anions both .

do anybody has idea how should i write msd command so that that i can calculate anion.msd and cation.msd both for wall and bulk regions.???

​trivial. compute msd operates on groups. so all you have to do is to define new (sub-)groups that only contain your cations or anions and run compute msd on those instead of all atoms in those groups.

axel.​

 


region bulk block 46 70  0 50  -12 42
region wall block 80 120  0 50  -12 42


compute mymsd1 wall  msd com yes
fix  mymsd1  wall ave/time 1 1 500 c_mymsd1[4] file wall.msd

compute mymsd2 bulk msd com yes
fix  mymsd2  bulk ave/time 1 1 500 c_mymsd2[4] file bulk.msd


help!!!



--
Dr. Axel Kohlmeyer  akohlmey@...92......  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.