From: Ajasja Ljubetič (
Date: Fri Oct 29 2010 - 01:41:51 CDT

This is more appropriate for the NAMD mailing list.
But anyway, your system is not minimized, you probably have some steric
clashes. Try to repeat the minimization, or perhaps try turning the rigid
bonds off during the equilibration...


On Fri, Oct 29, 2010 at 06:39, surendra jain <> wrote:

> Hi everyone,
> I am trying to heat a protein+water system from 0K to 300K in NPT
> ensemble. but while starting the dynamics I get this error :
> Error : Constraint failure in RATTLE algorithm for atom 268
> ERROR: Constraint failure; simulation has become unstable
> and it gives this error for a number of atoms. I am using a timestep of 1
> fs for the heating step. Can anyone please tell me how to remedy this error.
> I am attaching the input file with the message.
> Thanks,
> Surendra