[gmx-users] Trjcat append error

[Rosanne Zeiler]

  Dear all,

I've been trying to concatenate three .xtc files with some overlapping 
frames. The simplest way:

trjcat -f 1.xtc 2.xtc 3.xtc -o 4.xtc

worked very well but was slow. The second way:

trjcat -f 1.xtc 2.xtc 3.xtc -o 1.xtc

kept some overlapping frames between 1 en 2, just as the help tells you 
actually. So far no real problems
Then I wanted to append since 1.xtc is the biggest file without the 
overlapping frames so I tried:

trjcat -f 1.xtc 2.xtc 3.xtc -o 1.xtc -overwrite

trjcat now gives the following error:

Will append to 1.xtc rather than creating a new file
Reading frame       1 time 74664.000
-------------------------------------------------------
Program trjcat_f, VERSION 4.5.1
Source code file: gmx_trjcat.c, line: 702

Fatal error:
Error seeking to append position.
For more information and tips for troubleshooting, please check the GROMACS
website at http://www.gromacs.org/Documentation/Errors
-------------------------------------------------------

I used gmxcheck to check 1.xtc and nothing seems to be wrong. I can just 
use the first method, but I was wondering if someone knows how to append 
in the correct way.

Thanks!

Rosanne