Re: ERROR: CALCULATED VDWA FORCE MAY NOT MATCH ENERGY! POSSIBLE BUG!

From: Axel Kohlmeyer (akohlmey_at_gmail.com)
Date: Mon Feb 17 2014 - 17:26:41 CST

On Mon, Feb 17, 2014 at 6:05 PM, Miss. State <swe31_at_msstate.edu> wrote:
>
> Hello All,
>
> I'm a new user to NAMD and to programming in general. I tried to execute a simulation and the same errors are prompted to my 'output' file. The same error appears whether I'm starting a run for the first time or attempting a restart. The error is as follows:
>
> "ERROR: CALCULATED VDWA FORCE MAY NOT MATCH ENERGY! POSSIBLE BUG!"
> "ERROR: CALCULATED VDWB FORCE MAY NOT MATCH ENERGY! POSSIBLE BUG!"
>
> I can find nothing on this matter. These errors along with the additional inconsistencies and imprecisions(as shown below) arise a concern. Is this something I should be worried about? Any help would be appreciated.

unless you provide some details, how to reproduce this message, i
doubt that anybody can help you. my guess would be that you have some
bad/incorrect data somewhere in your input for force field data.

axel.

>
> Thank You,
> Shalton Evans
>
>
>
>
> Info: INCONSISTENCY IN FAST TABLE ENERGY VS FORCE: 0.000290495 AT 0.251946
>
> Info: INCONSISTENCY IN SCOR TABLE ENERGY VS FORCE: 0.00028301 AT 6.05702
>
> Info: ABSOLUTE IMPRECISION IN VDWA TABLE ENERGY: 1.29247e-26 AT 6.07762
>
> Info: RELATIVE IMPRECISION IN VDWA TABLE ENERGY: 2.98169e-16 AT 6.07762
>
> Info: ABSOLUTE IMPRECISION IN VDWA TABLE FORCE: 1.03398e-25 AT 6.07762
>
> Info: RELATIVE IMPRECISION IN VDWA TABLE FORCE: 2.61536e-16 AT 6.07762
>
> Info: INCONSISTENCY IN VDWA TABLE ENERGY VS FORCE: 0.181616 AT 6.05702
>
> ERROR:
>
> ERROR: CALCULATED VDWA FORCE MAY NOT MATCH ENERGY! POSSIBLE BUG!
>
> ERROR:
>
> Info: ABSOLUTE IMPRECISION IN VDWB TABLE ENERGY: 4.23516e-22 AT 6.07762
>
> Info: RELATIVE IMPRECISION IN VDWB TABLE ENERGY: 1.86205e-16 AT 6.07762
>
> Info: ABSOLUTE IMPRECISION IN VDWB TABLE FORCE: 6.77626e-21 AT 6.07762
>
> Info: RELATIVE IMPRECISION IN VDWB TABLE FORCE: 3.23812e-16 AT 6.07762
>
> Info: INCONSISTENCY IN VDWB TABLE ENERGY VS FORCE: 0.431298 AT 6.05702
>
> TCL: This Program will record the time of first 'intercalation'
>
> Info: useSync: 1 useProxySync: 0
>
> ERROR:
>
> ERROR: CALCULATED VDWB FORCE MAY NOT MATCH ENERGY! POSSIBLE BUG!
>
> ERROR:
>

-- 
Dr. Axel Kohlmeyer  akohlmey_at_gmail.com  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.

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