DIHEDRAL_CORRELATION
This is part of the colvar module

Measure the correlation between a pair of dihedral angles

Examples
Glossary of keywords and components
The atoms involved can be specified using
ATOMS the set of 8 atoms that are being used to calculate this quantity. For more information on how to specify lists of atoms see Groups and Virtual Atoms
Options
NUMERICAL_DERIVATIVES ( default=off ) calculate the derivatives for these quantities numerically
NOPBC

( default=off ) ignore the periodic boundary conditions when calculating distances