Classification of dynamic communication patterns

Dynamic communication patterns may be of two types:

1. Reader unknown: These correspond to flow dependence arcs with a label of the form in the synchronization graph, such that the dependence solver cannot get an exact (or near exact) solution to the resulting dependence equations. When translated to our context, this means that the owner of , thread i, does not know which threads will need its data due to the use reference , and hence cannot send them the data in advance.
2. Writer unknown: These correspond to flow dependence arcs with a label of the form in the synchronization graph. Again, the dependence solver cannot get a sufficiently exact solution to the resulting dependence equations. In this case, the owner of does not know which thread will write its value of data due to the define reference . Hence, the owner computes rule cannot be enforced at compile time.