From: Zhong Wenyu (wyzhong78_at_163.com)
Date: Thu Jun 03 2004 - 09:02:01 CDT
Hi, Brian.
Thanks for your help. I found out the reason, the coordinate  guessed by psfgen made some  angles of 0 degree.
----- Original Message ----- 
From: "Brian Bennion" <brian_at_youkai.llnl.gov>
Cc: "NAMD" <namd-l_at_ks.uiuc.edu>
Sent: Thursday, June 03, 2004 5:04 AM
Subject: Re: namd-l: "GRADIENT TOLERANCE: nan", Why?
> 
> Hello,
> 
> This error is very suggestive of incorrectly built system box.  The atoms
> are nearly on top of each other according to the VDW entry, and bonds seem
> to be cut in half, making angle energies off the scale.
> 
> Recheck your box size and send your config file with psf and pdb files if
> you need more help.
> 
> Brian
> 
> 
> On Wed, 2 Jun 2004, Zhong Wenyu wrote:
> 
> > Hi.
> > I have constructed a system contains lipid and DNA and carbon nanotube.The parameters files I used are par_all27_prot_lipid.inp and par_all27_na.inp. I meet some problems in minmization.
> >
> > TCL: Minimizing for 1200 steps
> > PRESSURE: 0 nan nan nan nan nan nan nan nan nan
> > GPRESSURE: 0 nan nan nan nan nan nan nan nan nan
> > ETITLE:      TS           BOND          ANGLE          DIHED          IMPRP               ELECT            VDW       BOUNDARY           MISC        KINETIC               TOTAL           TEMP         TOTAL2         TOTAL3        TEMPAVG            PRESSURE      GPRESSURE         VOLUME       PRESSAVG      GPRESSAVG
> >
> > ENERGY:       0    126435.5317 -99999999.9999     16158.4504       246.0499        -690784.5080  99999999.9999         0.0000         0.0000         0.0000      -99999999.9999         0.0000 -99999999.9999 -99999999.9999         0.0000      -99999999.9999 -99999999.9999   2906800.0000 -99999999.9999 -99999999.9999
> >
> > INITIAL STEP: 1e-06
> > GRADIENT TOLERANCE: nan
> >
> > Then the computation hold on, neither stop nor continue work.
> > Anyone could help me?
> > Best regards.
> >
> > Wenyu Zhong
> 
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> **Brian Bennion, Ph.D.                                         **
> **Computational and Systems Biology Division                   **
> **Biology and Biotechnology Research Program                   **
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