Provided by: gromacs-data_2018.1-1_all 
NAME
gmx-order - Compute the order parameter per atom for carbon tails
SYNOPSIS
gmx order [-f [<.xtc/.trr/...>]] [-n [<.ndx>]] [-nr [<.ndx>]]
[-s [<.tpr>]] [-o [<.xvg>]] [-od [<.xvg>]] [-ob [<.pdb>]]
[-os [<.xvg>]] [-Sg [<.xvg>]] [-Sk [<.xvg>]]
[-Sgsl [<.xvg>]] [-Sksl [<.xvg>]] [-b <time>] [-e <time>]
[-dt <time>] [-[no]w] [-xvg <enum>] [-d <enum>] [-sl <int>]
[-[no]szonly] [-[no]unsat] [-[no]permolecule] [-[no]radial]
[-[no]calcdist]
DESCRIPTION
gmx order computes the order parameter per atom for carbon tails. For atom i the vector i-1, i+1 is used
together with an axis. The index file should contain only the groups to be used for calculations, with
each group of equivalent carbons along the relevant acyl chain in its own group. There should not be any
generic groups (like System, Protein) in the index file to avoid confusing the program (this is not
relevant to tetrahedral order parameters however, which only work for water anyway).
gmx order can also give all diagonal elements of the order tensor and even calculate the deuterium order
parameter Scd (default). If the option -szonly is given, only one order tensor component (specified by
the -d option) is given and the order parameter per slice is calculated as well. If -szonly is not
selected, all diagonal elements and the deuterium order parameter is given.
The tetrahedrality order parameters can be determined around an atom. Both angle an distance order
parameters are calculated. See P.-L. Chau and A.J. Hardwick, Mol. Phys., 93, (1998), 511-518. for more
details.
OPTIONS
Options to specify input files:
-f [<.xtc/.trr/…>] (traj.xtc)
Trajectory: xtc trr cpt gro g96 pdb tng
-n [<.ndx>] (index.ndx)
Index file
-nr [<.ndx>] (index.ndx) (Optional)
Index file
-s [<.tpr>] (topol.tpr)
Portable xdr run input file
Options to specify output files:
-o [<.xvg>] (order.xvg)
xvgr/xmgr file
-od [<.xvg>] (deuter.xvg)
xvgr/xmgr file
-ob [<.pdb>] (eiwit.pdb) (Optional)
Protein data bank file
-os [<.xvg>] (sliced.xvg)
xvgr/xmgr file
-Sg [<.xvg>] (sg-ang.xvg) (Optional)
xvgr/xmgr file
-Sk [<.xvg>] (sk-dist.xvg) (Optional)
xvgr/xmgr file
-Sgsl [<.xvg>] (sg-ang-slice.xvg) (Optional)
xvgr/xmgr file
-Sksl [<.xvg>] (sk-dist-slice.xvg) (Optional)
xvgr/xmgr file
Other options:
-b <time> (0)
Time of first frame to read from trajectory (default unit ps)
-e <time> (0)
Time of last frame to read from trajectory (default unit ps)
-dt <time> (0)
Only use frame when t MOD dt = first time (default unit ps)
-[no]w (no)
View output .xvg, .xpm, .eps and .pdb files
-xvg <enum> (xmgrace)
xvg plot formatting: xmgrace, xmgr, none
-d <enum> (z)
Direction of the normal on the membrane: z, x, y
-sl <int> (1)
Calculate order parameter as function of box length, dividing the box into this number of slices.
-[no]szonly (no)
Only give Sz element of order tensor. (axis can be specified with -d)
-[no]unsat (no)
Calculate order parameters for unsaturated carbons. Note that this cannot be mixed with normal
order parameters.
-[no]permolecule (no)
Compute per-molecule Scd order parameters
-[no]radial (no)
Compute a radial membrane normal
-[no]calcdist (no)
Compute distance from a reference
SEE ALSO
gmx(1) More information about GROMACS is available at <http://www.gromacs.org/>.
COPYRIGHT
2018, GROMACS development team