This is part of the isdb module

Selects an argument based on the value of a SELECTOR.

Compulsory keywords

SELECTOR

name of the variable used to select

Options

NUMERICAL_DERIVATIVES

( default=off ) calculate the derivatives for these quantities numerically

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 proceding 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 componets 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...

Examples

In this example we use a simulated-tempering like approach activated by the RESCALE action. For each value of the rescale parameter, we perform an independent Parallel Bias Metadynamics simulation (see PBMETAD). At each moment of the simulation, only one of the PBMETAD actions is activated, based on the current value of the associated SELECTOR. The SELECT action can then be used to print out the value of the (active) PBMETAD bias potential.

ene:  ENERGY
d: DISTANCE ATOMS=1,2

SELECTOR NAME=GAMMA VALUE=0

pbmetad0: PBMETAD ARG=d SELECTOR=GAMMA SELECTOR_ID=0 SIGMA=0.1 PACE=500 HEIGHT=1 BIASFACTOR=8 FILE=HILLS.0
pbmetad1: PBMETAD ARG=d SELECTOR=GAMMA SELECTOR_ID=1 SIGMA=0.1 PACE=500 HEIGHT=1 BIASFACTOR=8 FILE=HILLS.1

RESCALE ...
LABEL=res ARG=ene,pbmetad0.bias,pbmetad1.bias TEMP=300
SELECTOR=GAMMA MAX_RESCALE=1.2 NOT_RESCALED=2 NBIN=2
W0=1000 BIASFACTOR=100.0 BSTRIDE=2000 BFILE=bias.dat
...

pbactive: SELECT ARG=pbmetad0.bias,pbmetad1.bias SELECTOR=GAMMA

PRINT ARG=pbactive STRIDE=100 FILE=COLVAR