SELECTOR

This is part of the isdb module

Defines a variable (of the type double) inside the PLUMED code that can be used and modified by other actions.

A SELECTOR can be used for example to activate or modify a bias based on its current value.

Examples

A typical example is the simulated-tempering like approach activated by RESCALE. In this example the total potential energy of the system is scaled by a parameter defined on a grid of dimension NBIN in the range from 1 to MAX_RESCALE. The value of the scaling parameter is determined by the current value of the SELECTOR GAMMA. The value of the SELECTOR is updated by a MC protocol inside the RESCALE class. A well-tempered metadynamics potential is used to enhance sampling in the SELECTOR space.

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

ene: ENERGY The ENERGY action with label ene calculates a single scalar value
SELECTOR 
NAME
compulsory keyword 
name of the SELECTOR 
=GAMMA 
VALUE
compulsory keyword 
set (initial) value of the SELECTOR 
=0 The SELECTOR action with label 
res: RESCALE ...
   
ARG
the input for this action is the scalar output from one or more other actions. 
=ene 
TEMP
compulsory keyword 
temperature 
=300 
   
SELECTOR
compulsory keyword 
name of the SELECTOR used for rescaling 
=GAMMA 
MAX_RESCALE
compulsory keyword 
maximum values for rescaling 
=1.2 
NBIN
compulsory keyword 
number of bins for gamma grid 
=2 
   
W0
 could not find this keyword 
=1000 
BIASFACTOR
compulsory keyword 
bias factor 
=100.0 
BSTRIDE
compulsory keyword 
stride for writing bias 
=2000 
BFILE
compulsory keyword 
file name for bias 
=bias.dat 
...The RESCALE action with label res calculates the following quantities:

 Quantity   
 Description  
res.bias
the instantaneous value of the bias potential
res.igamma
gamma parameter
res.accgamma
MC acceptance for gamma
res.wtbias
well-tempered bias


PRINT 
FILE
the name of the file on which to output these quantities 
=COLVAR 
ARG
the input for this action is the scalar output from one or more other actions. 
=* 
STRIDE
compulsory keyword ( default=1 )
the frequency with which the quantities of interest should be output 
=100 The PRINT action with label 

Glossary of keywords and components

Compulsory keywords

NAME	name of the SELECTOR
VALUE	set (initial) value of the SELECTOR