Re: Rattle algorithm Constraint failure - Reg

From: David Hardy (
Date: Fri Sep 07 2018 - 09:31:19 CDT

Dear Manikadan,

Obviously, this is due to running a vacuum bounded system with a barostat. The combination is not generally compatible. If you configure your simulation to output the cell basis vectors every step, you should see a substantial change in their lengths. The error is due to these lengths shrinking to the extent that it invalidates the original domain decomposition of the system.

Best regards,

David J. Hardy, Ph.D.
Beckman Institute
University of Illinois at Urbana-Champaign
405 N. Mathews Ave., Urbana, IL 61801,
> On Sep 7, 2018, at 5:46 AM, Mani Kandan <> wrote:
> Dear all,
>                          My simulation box has a size of 46x502x1502 A, where vacuum has a size of 46*452*502 A . Reaming box is filled with electrolyte and my membrane. When I am running NPT simulation, I am getting the following error:
> ERROR: Constraint failure in RATTLE algorithm for atom 433303!
> ERROR: Constraint failure; simulation has become unstable.
> ERROR: Exiting prematurely; see error messages above.
>                         Same system, When I am running with NVT simulation, it is running very well. Kindly help to resolve this issue. I want to run NPT simulation. 
> With Regards,

This archive was generated by hypermail 2.1.6 : Mon Dec 31 2018 - 23:21:23 CST