[gmx-users] Magic Number Error

[Mark Abraham]

alessandro casoni wrote:
> Dear GMX-USERS,
> I have a little problem...when I use g_covar I get this message:
> 
> Program g_covar, VERSION 3.3.2
> Source code file: xtcio.c, line: 83
> 
> Fatal error:
> Magic Number Error in XTC file (read 0, should be 1995)
> 
> 
> ..could you help me?

Use ls -l to check that your .xtc file has non-zero size. Otherwise, 
you've somehow managed to mangle the file so that the "magic" numbers at 
the start of the file (which confirm to GROMACS that this binary file is 
indeed suitably-constructed .xtc trajectory data) are not correct. This 
should not be caused merely by moving from big- to little-endian 
architecture (or vice-versa), but if you generated it on a different 
system to the one on which you're running g_covar, this would be a point 
of interest.

Mark