g_morph (1)

gmx morph [-f1 [<.gro/.g96/...>]] [-f2 [<.gro/.g96/...>]]

          [-o [<.xtc/.trr/...>]] [-or [<.xvg>]] [-n [<.ndx>]]
          [-nice <int>] [-[no]w] [-xvg <enum>] [-ninterm <int>]
          [-first <real>] [-last <real>] [-[no]fit]

gmx morph does a linear interpolation of conformations in order to create intermediates. Of course these are completely unphysical, but that you may try to justify yourself. Output is in the form of a generic trajectory. The number of intermediates can be controlled with the -ninterm flag. The first and last flag correspond to the way of interpolating: 0 corresponds to input structure 1 while 1 corresponds to input structure 2. If you specify -first 0 or -last 1 extrapolation will be on the path from input structure x_1 to x_2. In general, the coordinates of the intermediate x(i) out of N total intermediates correspond to:

x(i) = x_1 + (first+(i/(N-1))*(last-first))*(x_2-x_1)

Finally the RMSD with respect to both input structures can be computed if explicitly selected (-or option). In that case, an index file may be read to select the group from which the RMS is computed.

Options to specify input and output files:

-f1 [<.gro/.g96/...>] (conf1.gro) (Input)

    Structure file: gro g96 pdb brk ent esp tpr tpb tpa

-f2 [<.gro/.g96/...>] (conf2.gro) (Input)

    Structure file: gro g96 pdb brk ent esp tpr tpb tpa

-o [<.xtc/.trr/...>] (interm.xtc) (Output)

    Trajectory: xtc trr cpt trj gro g96 pdb tng

-or [<.xvg>] (rms-interm.xvg) (Output, Optional)

    xvgr/xmgr file

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

    Index file

Other options:

-nice <int> (0)

    Set the nicelevel

-[no]w (no)

    View output .xvg, .xpm, .eps and .pdb files

-xvg <enum> (xmgrace)

    xvg plot formatting: xmgrace, xmgr, none

-ninterm <int> (11)

    Number of intermediates

-first <real> (0)

    Corresponds to first generated structure (0 is input x_1, see above)

-last <real> (1)

    Corresponds to last generated structure (1 is input x_2, see above)

-[no]fit (yes)

    Do a least squares fit of the second to the first structure before interpolating

gromacs(7)

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