MULTI_RMSD
This is part of the colvar module

An alias to the MULTI-RMSD function.

Compulsory keywords
REFERENCE a file in pdb format containing the reference structure and the atoms involved in the CV.
TYPE ( default=MULTI-SIMPLE ) the manner in which RMSD alignment is performed. Should be MULTI-OPTIMAL, MULTI-OPTIMAL-FAST, MULTI-SIMPLE or MULTI-DRMSD.
Options
NUMERICAL_DERIVATIVES ( default=off ) calculate the derivatives for these quantities numerically
NOPBC ( default=off ) ignore the periodic boundary conditions when calculating distances
SQUARED

( default=off ) This should be set if you want the mean squared displacement instead of the root mean squared displacement

Examples

Just replace MULTI-RMSD with MULTI_RMSD

MULTI_RMSD REFERENCE=file.pdb TYPE=MULTI-DRMSD

and remember to use a pdb file like the one below to define the reference structure

ATOM      2  O   ALA     2      -0.926  -2.447  -0.497  1.00  1.00      DIA  O
ATOM      4  HNT ALA     2       0.533  -0.396   1.184  1.00  1.00      DIA  H
ATOM      6  HT1 ALA     2      -0.216  -2.590   1.371  1.00  1.00      DIA  H
ATOM      7  HT2 ALA     2      -0.309  -1.255   2.315  1.00  1.00      DIA  H
ATOM      8  HT3 ALA     2      -1.480  -1.560   1.212  1.00  1.00      DIA  H
ATOM      9  CAY ALA     2      -0.096   2.144  -0.669  1.00  1.00      DIA  C
ATOM     10  HY1 ALA     2       0.871   2.385  -0.588  1.00  1.00      DIA  H
TER
ATOM     12  HY3 ALA     2      -0.520   2.679  -1.400  1.00  1.00      DIA  H
ATOM     14  OY  ALA     2      -1.139   0.931  -0.973  1.00  1.00      DIA  O
ATOM     16  HN  ALA     2       1.713   1.021  -0.873  1.00  1.00      DIA  H
ATOM     18  HA  ALA     2       0.099  -0.774  -2.218  1.00  1.00      DIA  H
ATOM     19  CB  ALA     2       2.063  -1.223  -1.276  1.00  1.00      DIA  C
ATOM     20  HB1 ALA     2       2.670  -0.716  -2.057  1.00  1.00      DIA  H
ATOM     21  HB2 ALA     2       2.556  -1.051  -0.295  1.00  1.00      DIA  H
ATOM     22  HB3 ALA     2       2.070  -2.314  -1.490  1.00  1.00      DIA  H
END