[gmx-users] rlist has to be larger than rvdw when vdwtype = Shift ?

David spoel at xray.bmc.uu.se
Mon Jan 13 19:04:30 CET 2003

On Mon, 2003-01-13 at 18:14, Kun-Lin Yang wrote:
> Hello All, 
>     In the gromacs manual, page 132  (version 3.1.1), it is said that, "The neighbor search cut-off rlist should be 0.1 to 0.3 nm larger than rvdw (distance for LJ cutoff) to accommodate for the size of charge group.....", which  I think is very reasonable.  However, when I use
> vdwtype = Shift
> rlist=1.0
> rvdw=0.9
> rvdw_switch=0.8
> I got an error message:
> ERROR: rvdw must >= rlist
> How can this be?  I thought rlist should be larger than rvdw.  Same problem happens to rcoulomb and rlist, too.  Thanks in advance if anyone could answer my questions.  I'd very appreciate it. 
this is a known bug. You can disable it by modifying the
src/kernel/readir.c code that checks for this condition. However take
care with the shift functon for Coulomb, it may affect your results if
your force field isn't tuned for this functional form.

> BTW, GROMACS is awesome.. I love it!
> Kun-Lin, 1/13
Groeten, David.
Dr. David van der Spoel, 	Biomedical center, Dept. of Biochemistry
Husargatan 3, Box 576,  	75123 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://xray.bmc.uu.se/~spoel

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