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 stores 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).

Examples

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

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

d1: DISTANCE 
ATOMS
the pair of atom that we are calculating the distance between. 
=10,50 The DISTANCE action with label d1 calculates a single scalar value
d2: DISTANCE 
ATOMS
the pair of atom that we are calculating the distance between. 
=1,100 The DISTANCE action with label d2 calculates a single scalar value
d3: DISTANCE 
ATOMS
the pair of atom that we are calculating the distance between. 
=45,75 The DISTANCE action with label d3 calculates a single scalar value
st: STATS 
ARG
compulsory keyword 
the labels of the values from which the function is calculated 
=d1,d2,d3 
PARAMETERS
the parameters of the arguments in your function 
=1.5,4.0,2.0 The STATS action with label st calculates the following quantities:

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


PRINT 
ARG
compulsory keyword 
the labels of the values that you would like to print to the file 
=d1,d2,d3,st.* The PRINT action with label 

Glossary of keywords and components

Description of components

By default this Action calculates the following quantities. 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
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

Compulsory keywords

ARG	the labels of the values from which the function is calculated

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
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