STATS

This is part of the function module

Calculates statistical properties of a set of collective variables with respect to a set of reference values. In particular it calculates and store as components the sum of the squared deviations, the correlation, the slope and the intercept of a linear fit.

The reference values can be either provided as values using PARAMETERS or using value without derivatives from other actions using PARARG (for example using experimental values from collective variables such as CS2BACKBONE, RDC, NOE, PRE).

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 these customizable components the following quantities will always be output

Quantity	Description
sqdevsum	the sum of the squared deviations between arguments and parameters
corr	the correlation between arguments and parameters
slope	the slope of a linear fit between arguments and parameters
intercept	the intercept of a linear fit between arguments and parameters

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

Quantity	Keyword	Description
sqd	SQDEV	the squared deviations between arguments and parameters

Options

NUMERICAL_DERIVATIVES	( default=off ) calculate the derivatives for these quantities numerically
SQDEVSUM	( default=off ) calculates only SQDEVSUM
SQDEV	( default=off ) calculates and store the SQDEV as components
UPPERDISTS	( default=off ) calculates and store the SQDEV as components
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...
PARARG	the input for this action is the scalar output from one or more other actions without derivatives.
PARAMETERS	the parameters of the arguments in your function

Examples

The following input tells plumed to print the distance between three couple of atoms and compare them with three reference distances.

d1: DISTANCE ATOMS=10,50
d2: DISTANCE ATOMS=1,100
d3: DISTANCE ATOMS=45,75
st: STATS ARG=d1,d2,d3 PARAMETERS=1.5,4.0,2.0
PRINT ARG=d1,d2,d3,st.*