trjorder(1) orders molecules according to their distance to a group


trjorder -f traj.xtc -s topol.tpr -n index.ndx -o ordered.xtc -nshell nshell.xvg -[no]h -[no]version -nice int -b time -e time -dt time -xvg enum -na int -da int -[no]com -r real -[no]z


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.

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.


-f traj.xtc Input
 Trajectory: xtc trr trj gro g96 pdb cpt 

-s topol.tpr Input
 Structure+mass(db): tpr tpb tpa gro g96 pdb 

-n index.ndx Input, Opt.
 Index file 

-o ordered.xtc Output, Opt.
 Trajectory: xtc trr trj gro g96 pdb 

-nshell nshell.xvg Output, Opt.
 xvgr/xmgr file 


 Print help info and quit

 Print version info and quit

-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 or  none

-na int 3
 Number of atoms in a molecule

-da int 1
 Atom used for the distance calculation, 0 is COM

 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

 Order molecules on z-coordinate