Choice of Restraining Functions

The POTEntial statement allows one to select specific restraining functions for particular classes of distance restraints. By partitioning the distance restraints into particular classes, several restraining functions can be mixed. The total distance restraint energy $E_{NOE}$ is a sum over all classes of distance restraints:

$$E_{NOE} = \sum_{classes} \sum_{restraints} E_{NOE}^{class}$$ (20.6)

where the second sum is carried out over all distance restraints of the particular class. Each restraint corresponds to exactly one ASSIgn statement except for the SYMM, 3DPO, and HIGH restraining functions, where each restraint can comprise groups of ASSIgn statements.