Re: [AMBER] SHAKE error help

From: case <case.biomaps.rutgers.edu>
Date: Sat, 3 Sep 2011 08:50:13 -0400

On Fri, Sep 02, 2011, tsurma.umich.edu wrote:
>
> I am running a simple MD equilibration with CN- and K+ ions in ~500 H2O.
> When I have 1 CN-K+ in the system, it works perfectly. But, the moment I
> have 2K+CN- in H2O the SHAKE (ntc=3, ntf=3) is giving me this error:
>
>
> Coordinate resetting (SHAKE) cannot be accomplished,
> deviation is too large
> NITER, NIT, LL, I and J are : 0 0 2966 5 6

This means that atoms 5 and 6 are the ones where shake fails. Finding out
what those are (C and N?) might help. Make sure you have done some
minimization on the system; visualize where the K+ and CN- ions are; try
a short run with ntc=ntf=2. (Do you have any real need for ntc=3?)

...dac


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Received on Sat Sep 03 2011 - 06:00:02 PDT
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