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Re: [lammps-users] [EXTERNAL] Help lj/gromacs/coul/gromacs + pppm + respa + shake
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Re: [lammps-users] [EXTERNAL] Help lj/gromacs/coul/gromacs + pppm + respa + shake


From: "Moore, Stan" <stamoor@...3...>
Date: Thu, 27 Jul 2017 18:42:57 +0000

Please reply to the list, not to me.

 

You can’t use lj/gromacs/coul/gromacs with Kspace. It has a damping term for the coulombic interaction that is not compatible with long-range electrostatics. See http://lammps.sandia.gov/doc/pair_gromacs.html. You could try using pair hybrid with lj/gromacs + coul/long though or code up your own lj/gromacs/coul/long pair style.

 

Stan

 

From: Maria Silvina Moyano [mailto:silvina.moyano.zardain@...24...]
Sent: Thursday, July 27, 2017 12:22 PM
To: Moore, Stan <stamoor@...3...>
Subject: Re: [EXTERNAL] [lammps-users] Help lj/gromacs/coul/gromacs + pppm + respa + shake

 

Hello Stan,

 

Thanks for your reply. 

 

My problem is the following: I need to use the pair style lj/gromacs/coul/gromacs and compute long-range Coulombic interactions in reciprocal space. The manual doesn't mention how this pair style computes them.

 

On the other hand, the manual mentions that "All of the GROMACS pair styles can only be used via the pair keyword of the run_style respa command."  I don't understand which kspace works wtih that run_style.

 

Thanks in advance.

 

Silvina


Silvina Moyano

 

2017-07-27 12:20 GMT-03:00 Moore, Stan <stamoor@...3...>:

You must use a “*/coul/long” style with Kspace solver pppm.

Stan

 

From: Maria Silvina Moyano [mailto:silvina.moyano.zardain@...24...]
Sent: Thursday, July 27, 2017 9:08 AM
To: lammps-users@lists.sourceforge.net
Subject: [EXTERNAL] [lammps-users] Help lj/gromacs/coul/gromacs + pppm + respa + shake

 

Dear developers,

 

I am currently using Lammps 7th-Nov-2016.  I am attempting to use the pair style lj/gromacs/coul/gromacs with a kspace solver, more specifically the pppm solver, as part of a simualtion with the MARTINI force field with run_style respa, where the SHAKE alogrithm is also incorporated.

 

The relevant lines of the input are as follows

 

pair_style      lj/gromacs/coul/gromacs 9.0 12.0 0.000001 12

 

bond_style      harmonic

angle_style     cosine/squared

 

kspace_style    pppm 1.0e-5

 

special_bonds   lj/coul 0 1 1

 

read_data       ./lammps.data

 

run_style        respa 4 2 2 2 bond 1 angle 2 pair 3 kspace 4

 

I have performed multiple test simulations using 1 processor and so far I have only obtained the error message,

 

ERROR: KSpace style is incompatible with Pair style (../kspace.cpp:188)

 

I have used multiple different kspace solvers to overcome this error but the simulation with only run when no kspace solver is selected.

 

While I have read the manual, I do not fully understasnd how to implement this pair style with my the desired pppm solver.

 

Could you please explain how to perform a simulation using these four components, i.e. kspace pppm, pair style lj/gromacs/coul/gromacs fix id groupID shake and run style respa, in Lammps

 

Thanks in advance

 

Silvina