trjorder_d (1)

gmx trjorder [-f [<.xtc/.trr/...>]] [-s [<.tpr/.tpb/...>]]

             [-n [<.ndx>]] [-o [<.xtc/.trr/...>]] [-nshell [<.xvg>]]
             [-nice <int>] [-b <time>] [-e <time>] [-dt <time>]
             [-xvg <enum>] [-na <int>] [-da <int>] [-[no]com]
             [-r <real>] [-[no]z]

gmx trjorder orders molecules according to the smallest distance to atoms in a reference group or on z-coordinate (with option -z). With distance ordering, it will ask for a group of reference atoms and a group of molecules. For each frame of the trajectory the selected molecules will be reordered according to the shortest distance between atom number -da in the molecule and all the atoms in the reference group. The center of mass of the molecules can be used instead of a reference atom by setting -da to 0. All atoms in the trajectory are written to the output trajectory.

gmx trjorder can be useful for e.g. analyzing the n waters closest to a protein. In that case the reference group would be the protein and the group of molecules would consist of all the water atoms. When an index group of the first n waters is made, the ordered trajectory can be used with any Gromacs program to analyze the n closest waters.

If the output file is a .pdb file, the distance to the reference target will be stored in the B-factor field in order to color with e.g. Rasmol.

With option -nshell the number of molecules within a shell of radius -r around the reference group are printed.

Options to specify input and output files:

-f [<.xtc/.trr/...>] (traj.xtc) (Input)

    Trajectory: xtc trr cpt trj gro g96 pdb tng

-s [<.tpr/.tpb/...>] (topol.tpr) (Input)

    Structure+mass(db): tpr tpb tpa gro g96 pdb brk ent

-n [<.ndx>] (index.ndx) (Input, Optional)

    Index file

-o [<.xtc/.trr/...>] (ordered.xtc) (Output, Optional)

    Trajectory: xtc trr trj gro g96 pdb tng

-nshell [<.xvg>] (nshell.xvg) (Output, Optional)

    xvgr/xmgr file

Other options:

-nice <int> (19)

    Set the nicelevel

-b <time> (0)

    First frame (ps) to read from trajectory

-e <time> (0)

    Last frame (ps) to read from trajectory

-dt <time> (0)

    Only use frame when t MOD dt = first time (ps)

-xvg <enum> (xmgrace)

    xvg plot formatting: xmgrace, xmgr, none

-na <int> (3)

    Number of atoms in a molecule

-da <int> (1)

    Atom used for the distance calculation, 0 is COM

-[no]com (no)

    Use the distance to the center of mass of the reference group

-r <real> (0)

    Cutoff used for the distance calculation when computing the number of molecules in a shell around e.g. a protein

-[no]z (no)

    Order molecules on z-coordinate

gromacs(7)

More information about GROMACS is available at <http://www.gromacs.org/>.