[gmx-users] Precision in trajectory file

Berk Hess gmx3 at hotmail.com
Tue Aug 3 14:10:19 CEST 2010


Which program do want to print more digits?

PS please don't double post the same question on gmx-developers and gmx-users.


> Date: Tue, 3 Aug 2010 13:26:44 +0200
> From: qiaobf at gmail.com
> To: gmx-users at gromacs.org
> Subject: Re: [gmx-users] Precision in trajectory file
> The number of digits in .gro( or .pdb) is crudely fixed because of the
> format. Otherwise, it cannot be recognized by other softwares, like VMD.
> For the .trr files, I guess, if you are indeed running double-precision
> GMX, the leap-frog integrator is using double-precision coordinates, but
> the printed value in .trr is also truncated due to the format problem.
> Inon Sharony wrote:
> > Good afternoon!
> >
> > It seems to me that although I'm running a double-precision
> > installation of GROMACS, the printout to file (of the positions and
> > velocities) is of much less precision. i.e. the computation is done on
> > numbers with something like 16 significant digits, but the last 10 of
> > those are simply truncated and lost (e.g. positions are given in
> > single-precision as 0.000 nm, and in double-precision as 0.00000 nm).
> > Since I've already spent computation time at getting double-precision,
> > I'd like to make use of all of it -- for my own reasons. I already
> > searched the manuals, mailing lists and source code for instruction
> > but didn't find any.
> > Could you please tell me how I can change the number of digits printed
> > out (e.g. to the .trr file)? I'm looking for a more elegant solution
> > than adding a printf line to the source code. Something along the
> > lines of changing the format of numbers in the function that prints to
> > .trr .
> >
> > Thanks in advance!
> >
> -- 
> gmx-users mailing list    gmx-users at gromacs.org
> http://lists.gromacs.org/mailman/listinfo/gmx-users
> Please search the archive at http://www.gromacs.org/search before posting!
> Please don't post (un)subscribe requests to the list. Use the 
> www interface or send it to gmx-users-request at gromacs.org.
> Can't post? Read http://www.gromacs.org/mailing_lists/users.php
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20100803/eff4b355/attachment.html>

More information about the gromacs.org_gmx-users mailing list