	This is part of the contour module
	It is only available if you configure PLUMED with ./configure –enable-modules=contour . Furthermore, this feature is still being developed so take care when using it and report any problems on the mailing list.

Calculate the perpendicular distance from a Willard-Chandler dividing surface.

Examples

Glossary of keywords and components

Description of components

By default the value of the calculated quantity can be referenced elsewhere in the input file by using the label of the action. Alternatively this Action can be used to calculate the following quantities by employing the keywords listed below. These quantities can be referenced elsewhere in the input by using this Action's label followed by a dot and the name of the quantity required from the list below.

Quantity	Description
dist	the distance between the reference atom and the nearest contour
radius	the radial distance from the center of the contour to the edge

The atoms involved can be specified using

POSITIONS	the positions of the atoms that we are calculating the contour from. For more information on how to specify lists of atoms see Groups and Virtual Atoms
ATOM	The atom whose perpendicular distance we are calculating from the contour. For more information on how to specify lists of atoms see Groups and Virtual Atoms
ORIGIN	The position of the center of the region that the contour encloses. For more information on how to specify lists of atoms see Groups and Virtual Atoms

Compulsory keywords

BANDWIDTH	the bandwidths for kernel density esimtation
KERNEL	( default=GAUSSIAN ) the kernel function you are using. More details on the kernels available in plumed plumed can be found in kernelfunctions.
CUTOFF	( default=6.25 ) the cutoff at which to stop evaluating the kernel functions is set equal to sqrt(2x)bandwidth in each direction where x is this number
CONTOUR	the value we would like for the contour

Options

ARG

the input for this action is the scalar output from one or more other actions. The particular scalars that you will use are referenced using the label of the action. If the label appears on its own then it is assumed that the Action calculates a single scalar value. The value of this scalar is thus used as the input to this new action. If * or *.* appears the scalars calculated by all the proceeding actions in the input file are taken. Some actions have multi-component outputs and each component of the output has a specific label. For example a DISTANCE action labelled dist may have three components x, y and z. To take just the x component you should use dist.x, if you wish to take all three components then use dist.*.More information on the referencing of Actions can be found in the section of the manual on the PLUMED Getting Started. Scalar values can also be referenced using POSIX regular expressions as detailed in the section on Regular Expressions. To use this feature you you must compile PLUMED with the appropriate flag.. You can use multiple instances of this keyword i.e. ARG1, ARG2, ARG3...