Palabos源码：为什么define系列只作用在边界上呢

/** This method does nothing by default, unless overloaded in
 *  a deriving class. This is OK, because it's the behavior
 *  users will expect: if they use "defineSomething" on a cell,
 *  they want it to define the boundary condition on boundary
 *  nodes, but nothing to happen in bulk nodes. In this way,
 *  they can be lazy and loop over the whole domain instead
 *  of tracking boundary nodes explicitly.
 **/
template<typename T, template<typename U> class Descriptor>
vo