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

Add UPPER_WALL restraints on all the multicolvar values

This action takes the set of values calculated by the colvar specified by label in the DATA keyword and places a restraint on each quantity, \(x\), with the following functional form:

\( k((x-a+o)/s)^e \)

\(k\) (KAPPA) is an energy constant in internal unit of the code, \(s\) (EPS) a rescaling factor and \(e\) (EXP) the exponent determining the power law. By default: EXP = 2, EPS = 1.0, OFF = 0.

Examples

The following set of commands can be used to stop a cluster composed of 20 atoms subliming. The position of the center of mass of the cluster is calculated by the COM command labelled c1. The DISTANCES command labelled d1 is then used to calculate the distance between each of the 20 atoms in the cluster and the center of mass of the cluster. These distances are then passed to the UWALLS command, which adds a UPPER_WALLS restraint on each of them and thereby prevents each of them from moving very far from the center of mass of the cluster.

Click on the labels of the actions for more information on what each action computes

c1: COM ATOMSthe list of atoms which are involved the virtual atom's definition. 
=1-20 The COM action with label c1 calculates the position of a virtual atom
d1: DISTANCES GROUPACalculate the distances between all the atoms in GROUPA and all the atoms in GROUPB.
=c1 GROUPBCalculate the distances between all the atoms in GROUPA and all the atoms in GROUPB.
=1-20 The DISTANCES action with label d1
sr: UWALLS DATAcompulsory keyword 
certain actions in plumed work by calculating a list of variables and summing over
them. 
=d1 ATcompulsory keyword 
the radius of the sphere 
=2.5 KAPPAcompulsory keyword 
the force constant for the wall. 
=0.2 The UWALLS action with label sr calculates a single scalar value

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
bias	the instantaneous value of the bias potentials

In addition the following quantities can be calculated by employing the keywords listed below

Quantity	Keyword	Description
gradient	GRADIENT	the gradient
vmean	VMEAN	the norm of the mean vector. The output component can be referred to elsewhere in the input file by using the label.vmean
vsum	VSUM	the norm of sum of vectors. The output component can be referred to elsewhere in the input file by using the label.vsum
spath	SPATH	the position on the path
gspath	GPATH	the position on the path calculated using trigonometry
gzpath	GPATH	the distance from the path calculated using trigonometry
zpath	ZPATH	the distance from the path
altmin	ALT_MIN	the minimum value. This is calculated using the formula described in the description of the keyword so as to make it continuous.
between	BETWEEN	the number/fraction of values within a certain range. This is calculated using one of the formula described in the description of the keyword so as to make it continuous. You can calculate this quantity multiple times using different parameters.
highest	HIGHEST	the highest of the quantities calculated by this action
lessthan	LESS_THAN	the number of values less than a target value. This is calculated using one of the formula described in the description of the keyword so as to make it continuous. You can calculate this quantity multiple times using different parameters.
lowest	LOWEST	the lowest of the quantities calculated by this action
max	MAX	the maximum value. This is calculated using the formula described in the description of the keyword so as to make it continuous.
mean	MEAN	the mean value. The output component can be referred to elsewhere in the input file by using the label.mean
min	MIN	the minimum value. This is calculated using the formula described in the description of the keyword so as to make it continuous.
moment	MOMENTS	the central moments of the distribution of values. The second moment would be referenced elsewhere in the input file using label.moment-2, the third as label.moment-3, etc.
morethan	MORE_THAN	the number of values more than a target value. This is calculated using one of the formula described in the description of the keyword so as to make it continuous. You can calculate this quantity multiple times using different parameters.
sum	SUM	the sum of values

Compulsory keywords

DATA	certain actions in plumed work by calculating a list of variables and summing over them. This particular action can be used to calculate functions of these base variables or prints them to a file. This keyword thus takes the label of one of those such variables as input.
AT	the radius of the sphere
KAPPA	the force constant for the wall. The k_i in the expression for a wall.
OFFSET	( default=0.0 ) the offset for the start of the wall. The o_i in the expression for a wall.
EXP	( default=2.0 ) the powers for the walls. The e_i in the expression for a wall.
EPS	( default=1.0 ) the values for s_i in the expression for a wall

Options

NUMERICAL_DERIVATIVES	( default=off ) calculate the derivatives for these quantities numerically
SERIAL	( default=off ) do the calculation in serial. Do not use MPI
LOWMEM	( default=off ) lower the memory requirements
TIMINGS	( default=off ) output information on the timings of the various parts of the calculation