SidePtrHelper

Description

SidePtrHelper is a helper class for generating Elem objects that represent the side element of another Elem.

The standard method of building an element side in libMesh is Elem::side_ptr(). This method constructs a new Elem object every time it is called, which can be expensive if done repeatedly.

SidePtrHelper cheapens this process by retaining its own Elem objects, which have their points changed on request of an element side.