From: surendra jain (
Date: Thu Oct 28 2010 - 23:39:30 CDT

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.