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Thanks for both replies.<br>
<br>
I would like the trajectory information (i.e. positions and velocities)
as well as forces (which, as I understand it, can also be printed to
the same trajectory file) to be output with a larger (user defined?)
precision. I think the "program" which should do this is mdrun. <br>
I also noticed a function call for "write_traj" in the /src/kernel/md.c
file. I also looked in static.c as well as trnio.c and could not find
what I was looking for (an fprintf line which prints formated
coordinates to trajectory file, and specifies the precision of that
format).<br>
<br>
Inon.<br>
<br>
On 08/03/2010 03:10 PM, Berk Hess wrote:
<blockquote cite="mid:COL113-W450D756F5D75868DF479338EAE0@phx.gbl"
type="cite">
<style><!--
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--></style>Hi,<br>
<br>
Which program do want to print more digits?<br>
<br>
PS please don't double post the same question on gmx-developers and
gmx-users.<br>
<br>
Berk<br>
<br>
> Date: Tue, 3 Aug 2010 13:26:44 +0200<br>
> From: <a class="moz-txt-link-abbreviated" href="mailto:qiaobf@gmail.com">qiaobf@gmail.com</a><br>
> To: <a class="moz-txt-link-abbreviated" href="mailto:gmx-users@gromacs.org">gmx-users@gromacs.org</a><br>
> Subject: Re: [gmx-users] Precision in trajectory file<br>
> <br>
> <br>
> The number of digits in .gro( or .pdb) is crudely fixed because of
the<br>
> format. Otherwise, it cannot be recognized by other softwares,
like VMD.<br>
> <br>
> For the .trr files, I guess, if you are indeed running
double-precision<br>
> GMX, the leap-frog integrator is using double-precision
coordinates, but<br>
> the printed value in .trr is also truncated due to the format
problem.<br>
> <br>
> <br>
> <br>
> Inon Sharony wrote:<br>
> > Good afternoon!<br>
> ><br>
> > It seems to me that although I'm running a double-precision<br>
> > installation of GROMACS, the printout to file (of the
positions and<br>
> > velocities) is of much less precision. i.e. the computation
is done on<br>
> > numbers with something like 16 significant digits, but the
last 10 of<br>
> > those are simply truncated and lost (e.g. positions are given
in<br>
> > single-precision as 0.000 nm, and in double-precision as
0.00000 nm).<br>
> > Since I've already spent computation time at getting
double-precision,<br>
> > I'd like to make use of all of it -- for my own reasons. I
already<br>
> > searched the manuals, mailing lists and source code for
instruction<br>
> > but didn't find any.<br>
> > Could you please tell me how I can change the number of
digits printed<br>
> > out (e.g. to the .trr file)? I'm looking for a more elegant
solution<br>
> > than adding a printf line to the source code. Something along
the<br>
> > lines of changing the format of numbers in the function that
prints to<br>
> > .trr .<br>
> ><br>
> > Thanks in advance!<br>
> ><br>
> <br>
> -- <br>
> gmx-users mailing list <a class="moz-txt-link-abbreviated" href="mailto:gmx-users@gromacs.org">gmx-users@gromacs.org</a><br>
> <a class="moz-txt-link-freetext" href="http://lists.gromacs.org/mailman/listinfo/gmx-users">http://lists.gromacs.org/mailman/listinfo/gmx-users</a><br>
> Please search the archive at <a class="moz-txt-link-freetext" href="http://www.gromacs.org/search">http://www.gromacs.org/search</a> before
posting!<br>
> Please don't post (un)subscribe requests to the list. Use the <br>
> www interface or send it to <a class="moz-txt-link-abbreviated" href="mailto:gmx-users-request@gromacs.org">gmx-users-request@gromacs.org</a>.<br>
> Can't post? Read <a class="moz-txt-link-freetext" href="http://www.gromacs.org/mailing_lists/users.php">http://www.gromacs.org/mailing_lists/users.php</a><br>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Inon Sharony
ינון שרוני
972-3-6407634
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</pre>
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