[gmx-users] calculation of tilt angle of helix against the bilayer normal

[SHAHEE ISLAM]

hi,
i want to calculate the tilt angle of helix against the bilayer normal. iam
using this command
*gmx helixorient -s *.tpr -f *.xtc -n helix.ndx -oaxis -ocenter -orise
-oradius -otwist -obending -otilt -orot*
my question
1. how can i calculate the angle, so that angle can be calculated against
the bilayer normal.
2. by using this command i am able to analyse for 1 us coarse grained
simulation. But for the next 1 us run i am getting this error
 error too many iterations in routine jacobi
can anyone please guide me.
thanking you
shahee