Provided by: gromacs-data_2025.2-1_all bug

NAME
       gmx-rms - Calculate RMSDs with a reference structure and RMSD matrices


SYNOPSIS
          gmx rms [-s [<.tpr/.gro/...>]] [-f [<.xtc/.trr/...>]]
                  [-f2 [<.xtc/.trr/...>]] [-n [<.ndx>]] [-o [<.xvg>]]
                  [-mir [<.xvg>]] [-a [<.xvg>]] [-dist [<.xvg>]] [-m [<.xpm>]]
                  [-bin [<.dat>]] [-bm [<.xpm>]] [-b <time>] [-e <time>]
                  [-dt <time>] [-tu <enum>] [-[no]w] [-xvg <enum>]
                  [-what <enum>] [-[no]pbc] [-fit <enum>] [-prev <int>]
                  [-[no]split] [-skip <int>] [-skip2 <int>] [-max <real>]
                  [-min <real>] [-bmax <real>] [-bmin <real>] [-[no]mw]
                  [-nlevels <int>] [-ng <int>]


DESCRIPTION
       gmx  rms compares two structures by computing the root mean square deviation (RMSD), the size-independent
       rho similarity parameter (rho) or the scaled rho (rhosc), see Maiorov & Crippen, Proteins 22, 273 (1995).
       This is selected by -what.

       Each structure from a trajectory (-f) is compared to a reference structure. The  reference  structure  is
       taken from the structure file (-s).

       With  option -mir also a comparison with the mirror image of the reference structure is calculated.  This
       is useful as a reference for 'significant' values, see Maiorov & Crippen, Proteins 22, 273 (1995).

       Option -prev produces the comparison with a previous frame the specified number of frames ago.

       Option -m produces a matrix in .xpm format of comparison values of each structure in the trajectory  with
       respect to each other structure. This file can be visualized with for instance xv and can be converted to
       postscript with gmx xpm2ps.

       Option  -fit  controls  the  least-squares  fitting  of the structures on top of each other: complete fit
       (rotation and translation), translation only, or no fitting at all.

       Option -mw controls whether mass weighting is done or not.  If you select the option (default) and supply
       a valid .tpr file masses will be taken from  there,  otherwise  the  masses  will  be  deduced  from  the
       atommass.dat  file  in  GMXLIB  (deprecated).  This  is  fine for proteins, but not necessarily for other
       molecules. You can check whether this happened by turning on the -debug flag and inspecting the log file.

       With -f2, the 'other structures' are taken from a second trajectory, this generates a  comparison  matrix
       of one trajectory versus the other.

       Option -bin does a binary dump of the comparison matrix.

       Option  -bm  produces  a matrix of average bond angle deviations analogously to the -m option. Only bonds
       between atoms in the comparison group are considered.


OPTIONS
       Options to specify input files:

       -s [<.tpr/.gro/...>] (topol.tpr)
              Structure+mass(db): tpr gro g96 pdb brk ent

       -f [<.xtc/.trr/...>] (traj.xtc)
              Trajectory: xtc trr cpt gro g96 pdb tng

       -f2 [<.xtc/.trr/...>] (traj.xtc) (Optional)
              Trajectory: xtc trr cpt gro g96 pdb tng

       -n [<.ndx>] (index.ndx) (Optional)
              Index file

       Options to specify output files:

       -o [<.xvg>] (rmsd.xvg)
              xvgr/xmgr file

       -mir [<.xvg>] (rmsdmir.xvg) (Optional)
              xvgr/xmgr file

       -a [<.xvg>] (avgrp.xvg) (Optional)
              xvgr/xmgr file

       -dist [<.xvg>] (rmsd-dist.xvg) (Optional)
              xvgr/xmgr file

       -m [<.xpm>] (rmsd.xpm) (Optional)
              X PixMap compatible matrix file

       -bin [<.dat>] (rmsd.dat) (Optional)
              Generic data file

       -bm [<.xpm>] (bond.xpm) (Optional)
              X PixMap compatible matrix 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)

       -tu <enum> (ps)
              Unit for time values: fs, ps, ns, us, ms, s

       -[no]w (no)
              View output .xvg, .xpm, .eps and .pdb files

       -xvg <enum> (xmgrace)
              xvg plot formatting: xmgrace, xmgr, none

       -what <enum> (rmsd)
              Structural difference measure: rmsd, rho, rhosc

       -[no]pbc (yes)
              PBC check

       -fit <enum> (rot+trans)
              Fit to reference structure: rot+trans, translation, none

       -prev <int> (0)
              Compare with previous frame

       -[no]split (no)
              Split graph where time is zero

       -skip <int> (1)
              Only write every nr-th frame to matrix

       -skip2 <int> (1)
              Only write every nr-th frame to matrix

       -max <real> (-1)
              Maximum level in comparison matrix

       -min <real> (-1)
              Minimum level in comparison matrix

       -bmax <real> (-1)
              Maximum level in bond angle matrix

       -bmin <real> (-1)
              Minimum level in bond angle matrix

       -[no]mw (yes)
              Use mass weighting for superposition

       -nlevels <int> (80)
              Number of levels in the matrices

       -ng <int> (1)
              Number of groups to compute RMS between


SEE ALSO
       gmx(1)

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


COPYRIGHT
       2025, GROMACS development team

2025.2                                            May 12, 2025                                        GMX-RMS(1)