VMD-L Mailing List

From: Nuno Loureiro Ferreira (nunolf_at_ci.uc.pt)
Date: Sat Aug 25 2007 - 23:27:28 CDT

Ok John.
Now I know the reason.
Thanks.
N.

John Stone wrote:
> Hi,
> The main reason you get a different number of digits is that VMD
> doesn't care what the original number of decimal places was, as it stores
> all coordinates as 32-bit IEEE-754 floating point numbers internally,
> regardless what type of file the molecule originally came from. Even the
> number of decimal places in the PDB isn't particularly meaningful, as
> the more interesting fact would be how good the crystallographic resolution
> is, rather than the decimal precision limits of the file format itself.
> In any case, VMD stores things with much higher precision than PDB formats
> internally, since VMD also works with binary file formats that contain
> far more precise atom coordinates etc. If you want fewer decimal places
> in output for example, you can use the Tcl "format" command to emit the
> atom coordinates with however many decimal places you prefer.
>
> Cheers,
> John Stone
> vmd_at_ks.uiuc.edu
>
> On Sun, Aug 26, 2007 at 12:10:02AM +0100, Nuno Loureiro Ferreira wrote:
>
>> Hi *
>>
>> I loaded a regular pdb (e.g. through mol pdbload).
>> I wonder why a "$sel get x" command in the console gives me 10 decimal
>> digits for each atom in $sel?
>> A pdb commonly has only 3 digits.
>> Cheers,
>>
>> Nuno.
>> P.S. 1.8.6
>>
>
>