CONSTANT
This is part of the colvar module

Return one or more constant quantities with or without derivatives.

Useful in combination with functions that takes in input constants or parameters.

Description of components

The names of the components in this action can be customized by the user in the actions input file. However, in addition to the components that can be customized the following quantities will always be output

Quantity Description
v the # value
Options
NOPBC ( default=off ) ignore the periodic boundary conditions when calculating distances
NODERIV

( default=off ) Set to TRUE if you want values without derivatives.

VALUES The values of the constants
VALUE The value of the constant
Examples

The following input instructs plumed to compute the distance between atoms 1 and 2. If this distance is between 1.0 and 2.0, it is printed. If it is lower than 1.0 (larger than 2.0), 1.0 (2.0) is printed

cn: CONSTANT VALUES=1.0,2.0
dis: DISTANCE ATOMS=1,2
sss: SORT ARG=cn.v_0,dis,cn.v_1
PRINT ARG=sss.2

In case you want to pass a single value you can use VALUE:

cn: CONSTANT VALUE=1.0
dis: DISTANCE ATOMS=1,2
sss: SORT ARG=cn,dis
PRINT ARG=sss.1