Decorator for a sphere-like particle. 
 
Score on the lowest scoring pair of the refined pairs. 
 
Decorator for a sphere-like particle. 
 
Track the particles pairs passed to the pair score. 
 
A pair container with a decaying list of pairs. 
 
Score on end-to-end distance of freely jointed chain. 
 
Worm-like-chain score for polymer chains. 
 
A Score on the distance between a pair of particles. 
 
Return true for any pair of bonds sharing an endpoint.